[2705] | 1 | """Class Domain - |
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| 2 | 1D interval domains for finite-volume computations of |
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| 3 | the shallow water wave equation. |
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| 4 | |
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| 5 | This module contains a specialisation of class Domain from module domain.py |
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| 6 | consisting of methods specific to the Shallow Water Wave Equation |
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| 7 | |
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| 8 | |
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| 9 | U_t + E_x = S |
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| 10 | |
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| 11 | where |
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| 12 | |
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| 13 | U = [w, uh] |
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| 14 | E = [uh, u^2h + gh^2/2] |
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| 15 | S represents source terms forcing the system |
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| 16 | (e.g. gravity, friction, wind stress, ...) |
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| 17 | |
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| 18 | and _t, _x, _y denote the derivative with respect to t, x and y respectively. |
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| 19 | |
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| 20 | The quantities are |
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| 21 | |
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| 22 | symbol variable name explanation |
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| 23 | x x horizontal distance from origin [m] |
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| 24 | z elevation elevation of bed on which flow is modelled [m] |
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| 25 | h height water height above z [m] |
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| 26 | w stage absolute water level, w = z+h [m] |
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| 27 | u speed in the x direction [m/s] |
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| 28 | uh xmomentum momentum in the x direction [m^2/s] |
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| 29 | |
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| 30 | eta mannings friction coefficient [to appear] |
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| 31 | nu wind stress coefficient [to appear] |
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| 32 | |
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| 33 | The conserved quantities are w, uh |
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| 34 | |
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| 35 | For details see e.g. |
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| 36 | Christopher Zoppou and Stephen Roberts, |
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| 37 | Catastrophic Collapse of Water Supply Reservoirs in Urban Areas, |
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| 38 | Journal of Hydraulic Engineering, vol. 127, No. 7 July 1999 |
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| 39 | |
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| 40 | |
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| 41 | John Jakeman, Ole Nielsen, Stephen Roberts, Duncan Gray, Christopher Zoppou |
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| 42 | Geoscience Australia, 2006 |
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| 43 | """ |
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| 44 | |
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| 45 | from domain import * |
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| 46 | Generic_Domain = Domain #Rename |
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| 47 | |
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| 48 | #Shallow water domain |
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| 49 | class Domain(Generic_Domain): |
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| 50 | |
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| 51 | def __init__(self, coordinates, boundary = None, tagged_elements = None): |
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| 52 | |
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| 53 | conserved_quantities = ['stage', 'xmomentum'] |
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| 54 | other_quantities = ['elevation', 'friction'] |
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| 55 | Generic_Domain.__init__(self, coordinates, boundary, |
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| 56 | conserved_quantities, other_quantities, |
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| 57 | tagged_elements) |
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| 58 | |
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| 59 | from config import minimum_allowed_height, g |
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| 60 | self.minimum_allowed_height = minimum_allowed_height |
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| 61 | self.g = g |
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| 62 | |
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| 63 | #forcing terms not included in 1d domain ?WHy? |
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| 64 | self.forcing_terms.append(gravity) |
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| 65 | self.forcing_terms.append(manning_friction) |
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| 66 | #print "\nI have Removed forcing terms line 64 1dsw" |
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| 67 | |
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| 68 | #Realtime visualisation |
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| 69 | self.visualiser = None |
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| 70 | self.visualise = False |
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| 71 | self.visualise_color_stage = False |
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| 72 | self.visualise_stage_range = 1.0 |
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| 73 | self.visualise_timer = True |
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| 74 | self.visualise_range_z = None |
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| 75 | |
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| 76 | #Stored output |
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| 77 | self.store = True |
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| 78 | self.format = 'sww' |
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| 79 | self.smooth = True |
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| 80 | |
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| 81 | #Reduction operation for get_vertex_values |
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| 82 | from util import mean |
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| 83 | self.reduction = mean |
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| 84 | #self.reduction = min #Looks better near steep slopes |
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| 85 | |
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| 86 | self.quantities_to_be_stored = ['stage','xmomentum'] |
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| 87 | |
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| 88 | def set_quantities_to_be_stored(self, q): |
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| 89 | """Specify which quantities will be stored in the sww file. |
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| 90 | |
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| 91 | q must be either: |
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| 92 | - the name of a quantity |
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| 93 | - a list of quantity names |
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| 94 | - None |
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| 95 | |
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| 96 | In the two first cases, the named quantities will be stored at each |
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| 97 | yieldstep |
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| 98 | (This is in addition to the quantities elevation and friction) |
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| 99 | If q is None, storage will be switched off altogether. |
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| 100 | """ |
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| 101 | |
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| 102 | |
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| 103 | if q is None: |
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| 104 | self.quantities_to_be_stored = [] |
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| 105 | self.store = False |
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| 106 | return |
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| 107 | |
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| 108 | if isinstance(q, basestring): |
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| 109 | q = [q] # Turn argument into a list |
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| 110 | |
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| 111 | #Check correcness |
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| 112 | for quantity_name in q: |
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| 113 | msg = 'Quantity %s is not a valid conserved quantity' %quantity_name |
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| 114 | assert quantity_name in self.conserved_quantities, msg |
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| 115 | |
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| 116 | self.quantities_to_be_stored = q |
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| 117 | |
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| 118 | |
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| 119 | def initialise_visualiser(self,scale_z=1.0,rect=None): |
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| 120 | #Realtime visualisation |
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| 121 | if self.visualiser is None: |
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| 122 | from realtime_visualisation_new import Visualiser |
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| 123 | self.visualiser = Visualiser(self,scale_z,rect) |
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| 124 | self.visualiser.setup['elevation']=True |
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| 125 | self.visualiser.updating['stage']=True |
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| 126 | self.visualise = True |
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| 127 | if self.visualise_color_stage == True: |
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| 128 | self.visualiser.coloring['stage'] = True |
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| 129 | self.visualiser.qcolor['stage'] = (0.0, 0.0, 0.8) |
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| 130 | print 'initialise visualiser' |
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| 131 | print self.visualiser.setup |
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| 132 | print self.visualiser.updating |
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| 133 | |
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| 134 | def check_integrity(self): |
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| 135 | Generic_Domain.check_integrity(self) |
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| 136 | #Check that we are solving the shallow water wave equation |
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| 137 | |
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| 138 | msg = 'First conserved quantity must be "stage"' |
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| 139 | assert self.conserved_quantities[0] == 'stage', msg |
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| 140 | msg = 'Second conserved quantity must be "xmomentum"' |
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| 141 | assert self.conserved_quantities[1] == 'xmomentum', msg |
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| 142 | |
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| 143 | def extrapolate_second_order_sw(self): |
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| 144 | #Call correct module function |
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| 145 | #(either from this module or C-extension) |
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| 146 | extrapolate_second_order_sw(self) |
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| 147 | |
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| 148 | def compute_fluxes(self): |
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| 149 | #Call correct module function |
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| 150 | #(either from this module or C-extension) |
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| 151 | compute_fluxes(self) |
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| 152 | |
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| 153 | def distribute_to_vertices_and_edges(self): |
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| 154 | #Call correct module function |
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| 155 | #(either from this module or C-extension) |
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| 156 | distribute_to_vertices_and_edges(self) |
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| 157 | |
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| 158 | def evolve(self, yieldstep = None, finaltime = None, |
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| 159 | skip_initial_step = False): |
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| 160 | """Specialisation of basic evolve method from parent class |
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| 161 | """ |
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| 162 | |
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| 163 | #Call check integrity here rather than from user scripts |
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| 164 | #self.check_integrity() |
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| 165 | |
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| 166 | msg = 'Parameter beta_h must be in the interval [0, 1)' |
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| 167 | assert 0 <= self.beta_h < 1.0, msg |
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| 168 | msg = 'Parameter beta_w must be in the interval [0, 1)' |
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| 169 | assert 0 <= self.beta_w < 1.0, msg |
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| 170 | |
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| 171 | |
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| 172 | #Initial update of vertex and edge values before any storage |
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| 173 | #and or visualisation |
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| 174 | self.distribute_to_vertices_and_edges() |
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| 175 | |
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| 176 | #Initialise real time viz if requested |
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| 177 | if self.visualise is True and self.time == 0.0: |
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| 178 | if self.visualiser is None: |
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| 179 | self.initialise_visualiser() |
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| 180 | |
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| 181 | self.visualiser.update_timer() |
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| 182 | self.visualiser.setup_all() |
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| 183 | |
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| 184 | #Store model data, e.g. for visualisation |
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| 185 | if self.store is True and self.time == 0.0: |
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| 186 | self.initialise_storage() |
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| 187 | #print 'Storing results in ' + self.writer.filename |
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| 188 | else: |
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| 189 | pass |
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| 190 | #print 'Results will not be stored.' |
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| 191 | #print 'To store results set domain.store = True' |
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| 192 | #FIXME: Diagnostic output should be controlled by |
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| 193 | # a 'verbose' flag living in domain (or in a parent class) |
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| 194 | |
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| 195 | #Call basic machinery from parent class |
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| 196 | for t in Generic_Domain.evolve(self, yieldstep, finaltime, |
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| 197 | skip_initial_step): |
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| 198 | #Real time viz |
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| 199 | if self.visualise is True: |
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| 200 | self.visualiser.update_all() |
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| 201 | self.visualiser.update_timer() |
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| 202 | |
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| 203 | |
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| 204 | #Store model data, e.g. for subsequent visualisation |
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| 205 | if self.store is True: |
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| 206 | self.store_timestep(self.quantities_to_be_stored) |
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| 207 | |
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| 208 | #FIXME: Could maybe be taken from specified list |
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| 209 | #of 'store every step' quantities |
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| 210 | |
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| 211 | #Pass control on to outer loop for more specific actions |
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| 212 | yield(t) |
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| 213 | |
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| 214 | def initialise_storage(self): |
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| 215 | """Create and initialise self.writer object for storing data. |
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| 216 | Also, save x and bed elevation |
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| 217 | """ |
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| 218 | |
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| 219 | import data_manager |
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| 220 | |
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| 221 | #Initialise writer |
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| 222 | self.writer = data_manager.get_dataobject(self, mode = 'w') |
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| 223 | |
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| 224 | #Store vertices and connectivity |
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| 225 | self.writer.store_connectivity() |
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| 226 | |
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| 227 | |
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| 228 | def store_timestep(self, name): |
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| 229 | """Store named quantity and time. |
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| 230 | |
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| 231 | Precondition: |
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| 232 | self.write has been initialised |
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| 233 | """ |
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| 234 | self.writer.store_timestep(name) |
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| 235 | |
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| 236 | |
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| 237 | #=============== End of Shallow Water Domain =============================== |
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| 238 | |
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| 239 | #Rotation of momentum vector |
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| 240 | def rotate(q, normal, direction = 1): |
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| 241 | """Rotate the momentum component q (q[1], q[2]) |
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| 242 | from x,y coordinates to coordinates based on normal vector. |
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| 243 | |
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| 244 | If direction is negative the rotation is inverted. |
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| 245 | |
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| 246 | Input vector is preserved |
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| 247 | |
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| 248 | This function is specific to the shallow water wave equation |
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| 249 | """ |
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| 250 | |
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| 251 | from Numeric import zeros, Float |
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| 252 | |
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| 253 | assert len(q) == 3,\ |
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| 254 | 'Vector of conserved quantities must have length 3'\ |
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| 255 | 'for 2D shallow water equation' |
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| 256 | |
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| 257 | try: |
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| 258 | l = len(normal) |
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| 259 | except: |
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| 260 | raise 'Normal vector must be an Numeric array' |
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| 261 | |
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| 262 | assert l == 2, 'Normal vector must have 2 components' |
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| 263 | |
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| 264 | |
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| 265 | n1 = normal[0] |
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| 266 | n2 = normal[1] |
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| 267 | |
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| 268 | r = zeros(len(q), Float) #Rotated quantities |
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| 269 | r[0] = q[0] #First quantity, height, is not rotated |
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| 270 | |
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| 271 | if direction == -1: |
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| 272 | n2 = -n2 |
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| 273 | |
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| 274 | |
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| 275 | r[1] = n1*q[1] + n2*q[2] |
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| 276 | r[2] = -n2*q[1] + n1*q[2] |
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| 277 | |
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| 278 | return r |
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| 279 | |
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| 280 | |
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| 281 | # Flux computation |
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| 282 | #def flux_function(normal, ql, qr, zl, zr): |
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| 283 | def flux_function(ql, qr, zl, zr): |
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| 284 | """Compute fluxes between volumes for the shallow water wave equation |
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| 285 | cast in terms of w = h+z using the 'central scheme' as described in |
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| 286 | |
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| 287 | Kurganov, Noelle, Petrova. 'Semidiscrete Central-Upwind Schemes For |
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| 288 | Hyperbolic Conservation Laws and Hamilton-Jacobi Equations'. |
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| 289 | Siam J. Sci. Comput. Vol. 23, No. 3, pp. 707-740. |
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| 290 | |
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| 291 | The implemented formula is given in equation (3.15) on page 714 |
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| 292 | |
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| 293 | Conserved quantities w, uh, are stored as elements 0 and 1 |
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| 294 | in the numerical vectors ql an qr. |
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| 295 | |
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| 296 | Bed elevations zl and zr. |
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| 297 | """ |
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| 298 | |
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| 299 | from config import g, epsilon |
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| 300 | from math import sqrt |
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| 301 | from Numeric import array |
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| 302 | |
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| 303 | #Align momentums with x-axis |
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| 304 | #q_left = rotate(ql, normal, direction = 1) |
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| 305 | #q_right = rotate(qr, normal, direction = 1) |
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| 306 | q_left = ql |
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| 307 | q_right = qr |
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| 308 | |
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| 309 | z = (zl+zr)/2 #Take average of field values |
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| 310 | |
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| 311 | w_left = q_left[0] #w=h+z |
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| 312 | h_left = w_left-z |
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| 313 | uh_left = q_left[1] |
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| 314 | |
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| 315 | if h_left < epsilon: |
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| 316 | u_left = 0.0 #Could have been negative |
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| 317 | h_left = 0.0 |
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| 318 | else: |
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| 319 | u_left = uh_left/h_left |
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| 320 | |
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| 321 | |
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| 322 | w_right = q_right[0] #w=h+z |
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| 323 | h_right = w_right-z |
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| 324 | uh_right = q_right[1] |
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| 325 | |
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| 326 | |
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| 327 | if h_right < epsilon: |
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| 328 | u_right = 0.0 #Could have been negative |
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| 329 | h_right = 0.0 |
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| 330 | else: |
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| 331 | u_right = uh_right/h_right |
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| 332 | |
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| 333 | #vh_left = q_left[2] |
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| 334 | #vh_right = q_right[2] |
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| 335 | |
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| 336 | soundspeed_left = sqrt(g*h_left) |
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| 337 | soundspeed_right = sqrt(g*h_right) |
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| 338 | |
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| 339 | #Maximal wave speed |
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| 340 | #s_max = max(u_left+soundspeed_left, u_right+soundspeed_right, 0) |
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| 341 | s_max = max(u_left+soundspeed_left, u_right+soundspeed_right,0) |
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| 342 | |
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| 343 | #Minimal wave speed |
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| 344 | #s_min = min(u_left-soundspeed_left, u_right-soundspeed_right, 0) |
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| 345 | s_min = min(u_left-soundspeed_left, u_right-soundspeed_right,0) |
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| 346 | |
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| 347 | #Flux computation |
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| 348 | |
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| 349 | #FIXME(Ole): Why is it again that we don't |
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| 350 | #use uh_left and uh_right directly in the first entries? |
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| 351 | #flux_left = array([u_left*h_left, |
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| 352 | # u_left*uh_left + 0.5*g*h_left**2, |
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| 353 | # u_left*vh_left]) |
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| 354 | #flux_right = array([u_right*h_right, |
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| 355 | # u_right*uh_right + 0.5*g*h_right**2, |
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| 356 | # u_right*vh_right]) |
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| 357 | |
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| 358 | flux_left = array([u_left*h_left, |
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| 359 | u_left*uh_left + 0.5*g*h_left**2]) |
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| 360 | flux_right = array([u_right*h_right, |
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| 361 | u_right*uh_right + 0.5*g*h_right**2]) |
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| 362 | |
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| 363 | denom = s_max-s_min |
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| 364 | if denom == 0.0: |
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| 365 | edgeflux = array([0.0, 0.0, 0.0]) |
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| 366 | edgeflux = array([0.0, 0.0]) |
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| 367 | max_speed = 0.0 |
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| 368 | else: |
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| 369 | edgeflux = (s_max*flux_left - s_min*flux_right)/denom |
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| 370 | edgeflux += s_max*s_min*(q_right-q_left)/denom |
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| 371 | |
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| 372 | #edgeflux = rotate(edgeflux, normal, direction=-1) |
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| 373 | max_speed = max(abs(s_max), abs(s_min)) |
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| 374 | |
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| 375 | return edgeflux, max_speed |
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| 376 | |
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| 377 | def compute_fluxes(domain): |
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| 378 | """Compute all fluxes and the timestep suitable for all volumes |
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| 379 | in domain. |
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| 380 | |
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| 381 | Compute total flux for each conserved quantity using "flux_function" |
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| 382 | |
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| 383 | Fluxes across each edge are scaled by edgelengths and summed up |
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| 384 | Resulting flux is then scaled by area and stored in |
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| 385 | explicit_update for each of the three conserved quantities |
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| 386 | stage, xmomentum and ymomentum |
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| 387 | |
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| 388 | The maximal allowable speed computed by the flux_function for each volume |
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| 389 | is converted to a timestep that must not be exceeded. The minimum of |
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| 390 | those is computed as the next overall timestep. |
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| 391 | |
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| 392 | Post conditions: |
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| 393 | domain.explicit_update is reset to computed flux values |
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| 394 | domain.timestep is set to the largest step satisfying all volumes. |
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| 395 | """ |
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| 396 | |
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| 397 | import sys |
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| 398 | from Numeric import zeros, Float |
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| 399 | |
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| 400 | N = domain.number_of_elements |
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| 401 | |
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| 402 | #Shortcuts |
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| 403 | Stage = domain.quantities['stage'] |
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| 404 | Xmom = domain.quantities['xmomentum'] |
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| 405 | # Ymom = domain.quantities['ymomentum'] |
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| 406 | Bed = domain.quantities['elevation'] |
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| 407 | |
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| 408 | #Arrays |
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| 409 | stage = Stage.edge_values |
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| 410 | xmom = Xmom.edge_values |
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| 411 | # ymom = Ymom.edge_values |
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| 412 | bed = Bed.edge_values |
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| 413 | |
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| 414 | stage_bdry = Stage.boundary_values |
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| 415 | xmom_bdry = Xmom.boundary_values |
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| 416 | # ymom_bdry = Ymom.boundary_values |
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| 417 | |
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| 418 | # flux = zeros(3, Float) #Work array for summing up fluxes |
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| 419 | flux = zeros(2, Float) #Work array for summing up fluxes |
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| 420 | |
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| 421 | #Loop |
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| 422 | timestep = float(sys.maxint) |
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| 423 | for k in range(N): |
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| 424 | |
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| 425 | flux[:] = 0. #Reset work array |
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| 426 | #for i in range(3): |
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| 427 | for i in range(2): |
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| 428 | #Quantities inside volume facing neighbour i |
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| 429 | #ql = [stage[k, i], xmom[k, i], ymom[k, i]] |
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| 430 | ql = [stage[k, i], xmom[k, i]] |
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| 431 | zl = bed[k, i] |
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| 432 | |
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| 433 | #Quantities at neighbour on nearest face |
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| 434 | n = domain.neighbours[k,i] |
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| 435 | if n < 0: |
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| 436 | m = -n-1 #Convert negative flag to index |
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| 437 | #qr = [stage_bdry[m], xmom_bdry[m], ymom_bdry[m]] |
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| 438 | qr = [stage_bdry[m], xmom_bdry[m]] |
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| 439 | zr = zl #Extend bed elevation to boundary |
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| 440 | else: |
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| 441 | m = domain.neighbour_edges[k,i] |
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| 442 | #qr = [stage[n, m], xmom[n, m], ymom[n, m]] |
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| 443 | qr = [stage[n, m], xmom[n, m]] |
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| 444 | zr = bed[n, m] |
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| 445 | |
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| 446 | |
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| 447 | #Outward pointing normal vector |
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| 448 | normal = domain.normals[k, 2*i:2*i+2] |
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| 449 | #CHECK THIS LINE [k, 2*i:2*i+1] |
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| 450 | |
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| 451 | #Flux computation using provided function |
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| 452 | #edgeflux, max_speed = flux_function(normal, ql, qr, zl, zr) |
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| 453 | edgeflux, max_speed = flux_function(ql, qr, zl, zr) |
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| 454 | flux -= edgeflux * domain.edgelengths[k,i] |
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| 455 | |
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| 456 | #Update optimal_timestep |
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| 457 | try: |
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| 458 | timestep = min(timestep, 0.5*domain.radii[k]/max_speed) |
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| 459 | except ZeroDivisionError: |
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| 460 | pass |
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| 461 | |
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| 462 | #Normalise by area and store for when all conserved |
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| 463 | #quantities get updated |
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| 464 | flux /= domain.areas[k] |
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| 465 | Stage.explicit_update[k] = flux[0] |
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| 466 | Xmom.explicit_update[k] = flux[1] |
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| 467 | #Ymom.explicit_update[k] = flux[2] |
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| 468 | |
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| 469 | |
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| 470 | domain.timestep = timestep |
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| 471 | |
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| 472 | #see comments in the corresponding method in shallow_water_ext.c |
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| 473 | def extrapolate_second_order_sw_c(domain): |
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| 474 | """Wrapper calling C version of extrapolate_second_order_sw |
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| 475 | """ |
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| 476 | import sys |
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| 477 | from Numeric import zeros, Float |
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| 478 | |
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| 479 | N = domain.number_of_elements |
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| 480 | |
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| 481 | #Shortcuts |
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| 482 | Stage = domain.quantities['stage'] |
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| 483 | Xmom = domain.quantities['xmomentum'] |
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| 484 | # Ymom = domain.quantities['ymomentum'] |
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| 485 | from shallow_water_ext import extrapolate_second_order_sw |
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| 486 | extrapolate_second_order_sw(domain,domain.surrogate_neighbours, |
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| 487 | # cant find this in domain domain.number_of_boundaries, |
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| 488 | domain.centroid_coordinates, |
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| 489 | Stage.centroid_values, |
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| 490 | Xmom.centroid_values, |
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| 491 | # Ymom.centroid_values, |
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| 492 | domain.vertex_coordinates, |
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| 493 | Stage.vertex_values, |
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| 494 | Xmom.vertex_values)#, |
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| 495 | # Ymom.vertex_values) |
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| 496 | |
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| 497 | def compute_fluxes_c(domain): |
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| 498 | """Wrapper calling C version of compute fluxes |
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| 499 | """ |
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| 500 | |
---|
| 501 | import sys |
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| 502 | from Numeric import zeros, Float |
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| 503 | |
---|
| 504 | N = domain.number_of_elements |
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| 505 | |
---|
| 506 | #Shortcuts |
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| 507 | Stage = domain.quantities['stage'] |
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| 508 | Xmom = domain.quantities['xmomentum'] |
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| 509 | #Ymom = domain.quantities['ymomentum'] |
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| 510 | Bed = domain.quantities['elevation'] |
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| 511 | |
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| 512 | timestep = float(sys.maxint) |
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| 513 | from shallow_water_ext import compute_fluxes |
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| 514 | domain.timestep = compute_fluxes(timestep, domain.epsilon, domain.g, |
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| 515 | domain.neighbours, |
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| 516 | domain.neighbour_edges, |
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| 517 | domain.normals, |
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| 518 | domain.edgelengths, |
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| 519 | domain.radii, |
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| 520 | domain.areas, |
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| 521 | Stage.edge_values, |
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| 522 | Xmom.edge_values, |
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| 523 | #Ymom.edge_values, |
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| 524 | Bed.edge_values, |
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| 525 | Stage.boundary_values, |
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| 526 | Xmom.boundary_values, |
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| 527 | #Ymom.boundary_values, |
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| 528 | Stage.explicit_update, |
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| 529 | Xmom.explicit_update, |
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| 530 | #Ymom.explicit_update, |
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| 531 | domain.already_computed_flux) |
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| 532 | |
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| 533 | |
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| 534 | #################################### |
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| 535 | |
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| 536 | # Module functions for gradient limiting (distribute_to_vertices_and_edges) |
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| 537 | |
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| 538 | def distribute_to_vertices_and_edges(domain): |
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| 539 | """Distribution from centroids to vertices specific to the |
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| 540 | shallow water wave |
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| 541 | equation. |
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| 542 | |
---|
| 543 | It will ensure that h (w-z) is always non-negative even in the |
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| 544 | presence of steep bed-slopes by taking a weighted average between shallow |
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| 545 | and deep cases. |
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| 546 | |
---|
| 547 | In addition, all conserved quantities get distributed as per either a |
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| 548 | constant (order==1) or a piecewise linear function (order==2). |
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| 549 | |
---|
| 550 | FIXME: more explanation about removal of artificial variability etc |
---|
| 551 | |
---|
| 552 | Precondition: |
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| 553 | All quantities defined at centroids and bed elevation defined at |
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| 554 | vertices. |
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| 555 | |
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| 556 | Postcondition |
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| 557 | Conserved quantities defined at vertices |
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| 558 | |
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| 559 | """ |
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| 560 | |
---|
| 561 | from config import optimised_gradient_limiter |
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| 562 | |
---|
| 563 | #Remove very thin layers of water |
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| 564 | protect_against_infinitesimal_and_negative_heights(domain) |
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| 565 | |
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| 566 | #Extrapolate all conserved quantities |
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| 567 | if optimised_gradient_limiter: |
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| 568 | #MH090605 if second order, |
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| 569 | #perform the extrapolation and limiting on |
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| 570 | #all of the conserved quantitie |
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| 571 | |
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| 572 | if (domain.order == 1): |
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| 573 | for name in domain.conserved_quantities: |
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| 574 | Q = domain.quantities[name] |
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| 575 | Q.extrapolate_first_order() |
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| 576 | elif domain.order == 2: |
---|
| 577 | domain.extrapolate_second_order_sw() |
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| 578 | else: |
---|
| 579 | raise 'Unknown order' |
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| 580 | else: |
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| 581 | #old code: |
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| 582 | for name in domain.conserved_quantities: |
---|
| 583 | Q = domain.quantities[name] |
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| 584 | if domain.order == 1: |
---|
| 585 | Q.extrapolate_first_order() |
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| 586 | elif domain.order == 2: |
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| 587 | Q.extrapolate_second_order() |
---|
| 588 | Q.limit() |
---|
| 589 | else: |
---|
| 590 | raise 'Unknown order' |
---|
| 591 | |
---|
| 592 | |
---|
| 593 | #Take bed elevation into account when water heights are small |
---|
| 594 | balance_deep_and_shallow(domain) |
---|
| 595 | |
---|
| 596 | #Compute edge values by interpolation |
---|
| 597 | for name in domain.conserved_quantities: |
---|
| 598 | Q = domain.quantities[name] |
---|
| 599 | Q.interpolate_from_vertices_to_edges() |
---|
| 600 | |
---|
| 601 | |
---|
| 602 | def protect_against_infinitesimal_and_negative_heights(domain): |
---|
| 603 | """Protect against infinitesimal heights and associated high velocities |
---|
| 604 | """ |
---|
| 605 | |
---|
| 606 | #Shortcuts |
---|
| 607 | wc = domain.quantities['stage'].centroid_values |
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| 608 | zc = domain.quantities['elevation'].centroid_values |
---|
| 609 | xmomc = domain.quantities['xmomentum'].centroid_values |
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| 610 | # ymomc = domain.quantities['ymomentum'].centroid_values |
---|
| 611 | hc = wc - zc #Water depths at centroids |
---|
| 612 | |
---|
| 613 | #Update |
---|
| 614 | for k in range(domain.number_of_elements): |
---|
| 615 | |
---|
| 616 | if hc[k] < domain.minimum_allowed_height: |
---|
| 617 | #Control stage |
---|
| 618 | if hc[k] < domain.epsilon: |
---|
| 619 | wc[k] = zc[k] # Contain 'lost mass' error |
---|
| 620 | |
---|
| 621 | #Control momentum |
---|
| 622 | # xmomc[k] = ymomc[k] = 0.0 |
---|
| 623 | xmomc[k] = 0.0 |
---|
| 624 | |
---|
| 625 | def protect_against_infinitesimal_and_negative_heights_c(domain): |
---|
| 626 | """Protect against infinitesimal heights and associated high velocities |
---|
| 627 | """ |
---|
| 628 | |
---|
| 629 | #Shortcuts |
---|
| 630 | wc = domain.quantities['stage'].centroid_values |
---|
| 631 | zc = domain.quantities['elevation'].centroid_values |
---|
| 632 | # xmomc = domain.quantities['xmomentum'].centroid_values |
---|
| 633 | ymomc = domain.quantities['ymomentum'].centroid_values |
---|
| 634 | |
---|
| 635 | from shallow_water_ext import protect |
---|
| 636 | |
---|
| 637 | protect(domain.minimum_allowed_height, domain.epsilon, |
---|
| 638 | wc, zc, xmomc)#, ymomc) |
---|
| 639 | |
---|
| 640 | def h_limiter(domain): |
---|
| 641 | """Limit slopes for each volume to eliminate artificial variance |
---|
| 642 | introduced by e.g. second order extrapolator |
---|
| 643 | |
---|
| 644 | limit on h = w-z |
---|
| 645 | |
---|
| 646 | This limiter depends on two quantities (w,z) so it resides within |
---|
| 647 | this module rather than within quantity.py |
---|
| 648 | """ |
---|
| 649 | |
---|
| 650 | from Numeric import zeros, Float |
---|
| 651 | |
---|
| 652 | N = domain.number_of_elements |
---|
| 653 | beta_h = domain.beta_h |
---|
| 654 | |
---|
| 655 | #Shortcuts |
---|
| 656 | wc = domain.quantities['stage'].centroid_values |
---|
| 657 | zc = domain.quantities['elevation'].centroid_values |
---|
| 658 | hc = wc - zc |
---|
| 659 | |
---|
| 660 | wv = domain.quantities['stage'].vertex_values |
---|
| 661 | zv = domain.quantities['elevation'].vertex_values |
---|
| 662 | hv = wv-zv |
---|
| 663 | |
---|
| 664 | hvbar = zeros(hv.shape, Float) #h-limited values |
---|
| 665 | |
---|
| 666 | #Find min and max of this and neighbour's centroid values |
---|
| 667 | hmax = zeros(hc.shape, Float) |
---|
| 668 | hmin = zeros(hc.shape, Float) |
---|
| 669 | |
---|
| 670 | for k in range(N): |
---|
| 671 | hmax[k] = hmin[k] = hc[k] |
---|
| 672 | #for i in range(3): |
---|
| 673 | for i in range(2): |
---|
| 674 | n = domain.neighbours[k,i] |
---|
| 675 | if n >= 0: |
---|
| 676 | hn = hc[n] #Neighbour's centroid value |
---|
| 677 | |
---|
| 678 | hmin[k] = min(hmin[k], hn) |
---|
| 679 | hmax[k] = max(hmax[k], hn) |
---|
| 680 | |
---|
| 681 | |
---|
| 682 | #Diffences between centroids and maxima/minima |
---|
| 683 | dhmax = hmax - hc |
---|
| 684 | dhmin = hmin - hc |
---|
| 685 | |
---|
| 686 | #Deltas between vertex and centroid values |
---|
| 687 | dh = zeros(hv.shape, Float) |
---|
| 688 | #for i in range(3): |
---|
| 689 | for i in range(2): |
---|
| 690 | dh[:,i] = hv[:,i] - hc |
---|
| 691 | |
---|
| 692 | #Phi limiter |
---|
| 693 | for k in range(N): |
---|
| 694 | |
---|
| 695 | #Find the gradient limiter (phi) across vertices |
---|
| 696 | phi = 1.0 |
---|
| 697 | #for i in range(3): |
---|
| 698 | for i in range(2): |
---|
| 699 | r = 1.0 |
---|
| 700 | if (dh[k,i] > 0): r = dhmax[k]/dh[k,i] |
---|
| 701 | if (dh[k,i] < 0): r = dhmin[k]/dh[k,i] |
---|
| 702 | |
---|
| 703 | phi = min( min(r*beta_h, 1), phi ) |
---|
| 704 | |
---|
| 705 | #Then update using phi limiter |
---|
| 706 | #for i in range(3): |
---|
| 707 | for i in range(2): |
---|
| 708 | hvbar[k,i] = hc[k] + phi*dh[k,i] |
---|
| 709 | |
---|
| 710 | return hvbar |
---|
| 711 | |
---|
| 712 | |
---|
| 713 | |
---|
| 714 | def h_limiter_c(domain): |
---|
| 715 | """Limit slopes for each volume to eliminate artificial variance |
---|
| 716 | introduced by e.g. second order extrapolator |
---|
| 717 | |
---|
| 718 | limit on h = w-z |
---|
| 719 | |
---|
| 720 | This limiter depends on two quantities (w,z) so it resides within |
---|
| 721 | this module rather than within quantity.py |
---|
| 722 | |
---|
| 723 | Wrapper for c-extension |
---|
| 724 | """ |
---|
| 725 | |
---|
| 726 | from Numeric import zeros, Float |
---|
| 727 | |
---|
| 728 | N = domain.number_of_elements |
---|
| 729 | beta_h = domain.beta_h |
---|
| 730 | |
---|
| 731 | #Shortcuts |
---|
| 732 | wc = domain.quantities['stage'].centroid_values |
---|
| 733 | zc = domain.quantities['elevation'].centroid_values |
---|
| 734 | hc = wc - zc |
---|
| 735 | |
---|
| 736 | wv = domain.quantities['stage'].vertex_values |
---|
| 737 | zv = domain.quantities['elevation'].vertex_values |
---|
| 738 | hv = wv - zv |
---|
| 739 | |
---|
| 740 | #Call C-extension |
---|
| 741 | from shallow_water_ext import h_limiter_sw as h_limiter |
---|
| 742 | hvbar = h_limiter(domain, hc, hv) |
---|
| 743 | |
---|
| 744 | return hvbar |
---|
| 745 | |
---|
| 746 | def balance_deep_and_shallow(domain): |
---|
| 747 | """Compute linear combination between stage as computed by |
---|
| 748 | gradient-limiters limiting using w, and stage computed by |
---|
| 749 | gradient-limiters limiting using h (h-limiter). |
---|
| 750 | The former takes precedence when heights are large compared to the |
---|
| 751 | bed slope while the latter takes precedence when heights are |
---|
| 752 | relatively small. Anything in between is computed as a balanced |
---|
| 753 | linear combination in order to avoid numerical disturbances which |
---|
| 754 | would otherwise appear as a result of hard switching between |
---|
| 755 | modes. |
---|
| 756 | |
---|
| 757 | The h-limiter is always applied irrespective of the order. |
---|
| 758 | """ |
---|
| 759 | |
---|
| 760 | #Shortcuts |
---|
| 761 | wc = domain.quantities['stage'].centroid_values |
---|
| 762 | zc = domain.quantities['elevation'].centroid_values |
---|
| 763 | hc = wc - zc |
---|
| 764 | |
---|
| 765 | wv = domain.quantities['stage'].vertex_values |
---|
| 766 | zv = domain.quantities['elevation'].vertex_values |
---|
| 767 | hv = wv-zv |
---|
| 768 | |
---|
| 769 | #Limit h |
---|
| 770 | hvbar = h_limiter(domain) |
---|
| 771 | |
---|
| 772 | for k in range(domain.number_of_elements): |
---|
| 773 | #Compute maximal variation in bed elevation |
---|
| 774 | # This quantitiy is |
---|
| 775 | # dz = max_i abs(z_i - z_c) |
---|
| 776 | # and it is independent of dimension |
---|
| 777 | # In the 1d case zc = (z0+z1)/2 |
---|
| 778 | # In the 2d case zc = (z0+z1+z2)/3 |
---|
| 779 | |
---|
| 780 | dz = max(abs(zv[k,0]-zc[k]), |
---|
| 781 | abs(zv[k,1]-zc[k]))#, |
---|
| 782 | # abs(zv[k,2]-zc[k])) |
---|
| 783 | |
---|
| 784 | |
---|
| 785 | hmin = min( hv[k,:] ) |
---|
| 786 | |
---|
| 787 | #Create alpha in [0,1], where alpha==0 means using the h-limited |
---|
| 788 | #stage and alpha==1 means using the w-limited stage as |
---|
| 789 | #computed by the gradient limiter (both 1st or 2nd order) |
---|
| 790 | |
---|
| 791 | #If hmin > dz/2 then alpha = 1 and the bed will have no effect |
---|
| 792 | #If hmin < 0 then alpha = 0 reverting to constant height above bed. |
---|
| 793 | |
---|
| 794 | if dz > 0.0: |
---|
| 795 | alpha = max( min( 2*hmin/dz, 1.0), 0.0 ) |
---|
| 796 | else: |
---|
| 797 | #Flat bed |
---|
| 798 | alpha = 1.0 |
---|
| 799 | |
---|
| 800 | #Let |
---|
| 801 | # |
---|
| 802 | # wvi be the w-limited stage (wvi = zvi + hvi) |
---|
| 803 | # wvi- be the h-limited state (wvi- = zvi + hvi-) |
---|
| 804 | # |
---|
| 805 | # |
---|
| 806 | #where i=0,1,2 denotes the vertex ids |
---|
| 807 | # |
---|
| 808 | #Weighted balance between w-limited and h-limited stage is |
---|
| 809 | # |
---|
| 810 | # wvi := (1-alpha)*(zvi+hvi-) + alpha*(zvi+hvi) |
---|
| 811 | # |
---|
| 812 | #It follows that the updated wvi is |
---|
| 813 | # wvi := zvi + (1-alpha)*hvi- + alpha*hvi |
---|
| 814 | # |
---|
| 815 | # Momentum is balanced between constant and limited |
---|
| 816 | |
---|
| 817 | |
---|
| 818 | #for i in range(3): |
---|
| 819 | # wv[k,i] = zv[k,i] + hvbar[k,i] |
---|
| 820 | |
---|
| 821 | #return |
---|
| 822 | |
---|
| 823 | if alpha < 1: |
---|
| 824 | |
---|
| 825 | #for i in range(3): |
---|
| 826 | for i in range(2): |
---|
| 827 | wv[k,i] = zv[k,i] + (1-alpha)*hvbar[k,i] + alpha*hv[k,i] |
---|
| 828 | |
---|
| 829 | #Momentums at centroids |
---|
| 830 | xmomc = domain.quantities['xmomentum'].centroid_values |
---|
| 831 | # ymomc = domain.quantities['ymomentum'].centroid_values |
---|
| 832 | |
---|
| 833 | #Momentums at vertices |
---|
| 834 | xmomv = domain.quantities['xmomentum'].vertex_values |
---|
| 835 | # ymomv = domain.quantities['ymomentum'].vertex_values |
---|
| 836 | |
---|
| 837 | # Update momentum as a linear combination of |
---|
| 838 | # xmomc and ymomc (shallow) and momentum |
---|
| 839 | # from extrapolator xmomv and ymomv (deep). |
---|
| 840 | xmomv[k,:] = (1-alpha)*xmomc[k] + alpha*xmomv[k,:] |
---|
| 841 | # ymomv[k,:] = (1-alpha)*ymomc[k] + alpha*ymomv[k,:] |
---|
| 842 | |
---|
| 843 | |
---|
| 844 | def balance_deep_and_shallow_c(domain): |
---|
| 845 | """Wrapper for C implementation |
---|
| 846 | """ |
---|
| 847 | |
---|
| 848 | #Shortcuts |
---|
| 849 | wc = domain.quantities['stage'].centroid_values |
---|
| 850 | zc = domain.quantities['elevation'].centroid_values |
---|
| 851 | hc = wc - zc |
---|
| 852 | |
---|
| 853 | wv = domain.quantities['stage'].vertex_values |
---|
| 854 | zv = domain.quantities['elevation'].vertex_values |
---|
| 855 | hv = wv - zv |
---|
| 856 | |
---|
| 857 | #Momentums at centroids |
---|
| 858 | xmomc = domain.quantities['xmomentum'].centroid_values |
---|
| 859 | # ymomc = domain.quantities['ymomentum'].centroid_values |
---|
| 860 | |
---|
| 861 | #Momentums at vertices |
---|
| 862 | xmomv = domain.quantities['xmomentum'].vertex_values |
---|
| 863 | # ymomv = domain.quantities['ymomentum'].vertex_values |
---|
| 864 | |
---|
| 865 | #Limit h |
---|
| 866 | hvbar = h_limiter(domain) |
---|
| 867 | |
---|
| 868 | #This is how one would make a first order h_limited value |
---|
| 869 | #as in the old balancer (pre 17 Feb 2005): |
---|
| 870 | #from Numeric import zeros, Float |
---|
| 871 | #hvbar = zeros( (len(hc), 3), Float) |
---|
| 872 | #for i in range(3): |
---|
| 873 | # hvbar[:,i] = hc[:] |
---|
| 874 | |
---|
| 875 | from shallow_water_ext import balance_deep_and_shallow |
---|
| 876 | balance_deep_and_shallow(wc, zc, hc, wv, zv, hv, hvbar, |
---|
| 877 | # xmomc, ymomc, xmomv, ymomv) |
---|
| 878 | xmomc, xmomv) |
---|
| 879 | |
---|
| 880 | |
---|
| 881 | ############################################### |
---|
| 882 | #Boundaries - specific to the shallow water wave equation |
---|
| 883 | class Reflective_boundary(Boundary): |
---|
| 884 | """Reflective boundary returns same conserved quantities as |
---|
| 885 | those present in its neighbour volume but reflected. |
---|
| 886 | |
---|
| 887 | This class is specific to the shallow water equation as it |
---|
| 888 | works with the momentum quantities assumed to be the second |
---|
| 889 | and third conserved quantities. |
---|
| 890 | """ |
---|
| 891 | |
---|
| 892 | def __init__(self, domain = None): |
---|
| 893 | Boundary.__init__(self) |
---|
| 894 | |
---|
| 895 | if domain is None: |
---|
| 896 | msg = 'Domain must be specified for reflective boundary' |
---|
| 897 | raise msg |
---|
| 898 | |
---|
| 899 | #Handy shorthands |
---|
| 900 | self.stage = domain.quantities['stage'].edge_values |
---|
| 901 | self.xmom = domain.quantities['xmomentum'].edge_values |
---|
| 902 | #self.ymom = domain.quantities['ymomentum'].edge_values |
---|
| 903 | #self.normals = domain.normals |
---|
| 904 | |
---|
| 905 | from Numeric import zeros, Float |
---|
| 906 | #self.conserved_quantities = zeros(3, Float) |
---|
| 907 | self.conserved_quantities = zeros(2, Float) |
---|
| 908 | |
---|
| 909 | def __repr__(self): |
---|
| 910 | return 'Reflective_boundary' |
---|
| 911 | |
---|
| 912 | |
---|
| 913 | def evaluate(self, vol_id, edge_id): |
---|
| 914 | """Reflective boundaries reverses the outward momentum |
---|
| 915 | of the volume they serve. |
---|
| 916 | """ |
---|
| 917 | |
---|
| 918 | q = self.conserved_quantities |
---|
| 919 | q[0] = self.stage[vol_id, edge_id] |
---|
| 920 | q[1] = self.xmom[vol_id, edge_id] |
---|
| 921 | #q[2] = self.ymom[vol_id, edge_id] |
---|
| 922 | |
---|
| 923 | #normal = self.normals[vol_id, 2*edge_id:2*edge_id+2] |
---|
| 924 | #normal = self.normals[vol_id, 2*edge_id:2*edge_id+1] |
---|
| 925 | |
---|
| 926 | |
---|
| 927 | #r = rotate(q, normal, direction = 1) |
---|
| 928 | #r[1] = -r[1] |
---|
| 929 | #q = rotate(r, normal, direction = -1) |
---|
| 930 | r = q |
---|
| 931 | r[1] = -q[1] |
---|
| 932 | q = r |
---|
| 933 | |
---|
| 934 | return q |
---|
| 935 | |
---|
| 936 | |
---|
| 937 | ######################### |
---|
| 938 | #Standard forcing terms: |
---|
| 939 | # |
---|
| 940 | def gravity(domain): |
---|
| 941 | """Apply gravitational pull in the presence of bed slope |
---|
| 942 | """ |
---|
| 943 | |
---|
| 944 | from util import gradient |
---|
| 945 | from Numeric import zeros, Float, array, sum |
---|
| 946 | |
---|
| 947 | xmom = domain.quantities['xmomentum'].explicit_update |
---|
| 948 | # ymom = domain.quantities['ymomentum'].explicit_update |
---|
| 949 | |
---|
| 950 | Stage = domain.quantities['stage'] |
---|
| 951 | Elevation = domain.quantities['elevation'] |
---|
| 952 | h = Stage.edge_values - Elevation.edge_values |
---|
| 953 | v = Elevation.vertex_values |
---|
| 954 | |
---|
| 955 | x = domain.get_vertex_coordinates() |
---|
| 956 | g = domain.g |
---|
| 957 | |
---|
| 958 | for k in range(domain.number_of_elements): |
---|
| 959 | # avg_h = sum( h[k,:] )/3 |
---|
| 960 | avg_h = sum( h[k,:] )/2 |
---|
| 961 | |
---|
| 962 | #Compute bed slope |
---|
| 963 | #x0, y0, x1, y1, x2, y2 = x[k,:] |
---|
| 964 | x0, x1 = x[k,:] |
---|
| 965 | #z0, z1, z2 = v[k,:] |
---|
| 966 | z0, z1 = v[k,:] |
---|
| 967 | |
---|
| 968 | #zx, zy = gradient(x0, y0, x1, y1, x2, y2, z0, z1, z2) |
---|
| 969 | zx = gradient(x0, x1, z0, z1) |
---|
| 970 | |
---|
| 971 | #Update momentum |
---|
| 972 | xmom[k] += -g*zx*avg_h |
---|
| 973 | # ymom[k] += -g*zy*avg_h |
---|
| 974 | |
---|
| 975 | |
---|
| 976 | def graity_c(domain): |
---|
| 977 | """Wrapper calling C version |
---|
| 978 | """ |
---|
| 979 | |
---|
| 980 | xmom = domain.quantities['xmomentum'].explicit_update |
---|
| 981 | # ymom = domain.quantities['ymomentum'].explicit_update |
---|
| 982 | |
---|
| 983 | Stage = domain.quantities['stage'] |
---|
| 984 | Elevation = domain.quantities['elevation'] |
---|
| 985 | h = Stage.edge_values - Elevation.edge_values |
---|
| 986 | v = Elevation.vertex_values |
---|
| 987 | |
---|
| 988 | x = domain.get_vertex_coordinates() |
---|
| 989 | g = domain.g |
---|
| 990 | |
---|
| 991 | |
---|
| 992 | from shallow_water_ext import gravity |
---|
| 993 | gravity(g, h, v, x, xmom, ymom) |
---|
| 994 | |
---|
| 995 | |
---|
| 996 | def manning_friction(domain): |
---|
| 997 | """Apply (Manning) friction to water momentum |
---|
| 998 | """ |
---|
| 999 | |
---|
| 1000 | from math import sqrt |
---|
| 1001 | |
---|
| 1002 | w = domain.quantities['stage'].centroid_values |
---|
| 1003 | z = domain.quantities['elevation'].centroid_values |
---|
| 1004 | h = w-z |
---|
| 1005 | |
---|
| 1006 | uh = domain.quantities['xmomentum'].centroid_values |
---|
| 1007 | vh = domain.quantities['ymomentum'].centroid_values |
---|
| 1008 | eta = domain.quantities['friction'].centroid_values |
---|
| 1009 | |
---|
| 1010 | xmom_update = domain.quantities['xmomentum'].semi_implicit_update |
---|
| 1011 | ymom_update = domain.quantities['ymomentum'].semi_implicit_update |
---|
| 1012 | |
---|
| 1013 | N = domain.number_of_elements |
---|
| 1014 | eps = domain.minimum_allowed_height |
---|
| 1015 | g = domain.g |
---|
| 1016 | |
---|
| 1017 | for k in range(N): |
---|
| 1018 | if eta[k] >= eps: |
---|
| 1019 | if h[k] >= eps: |
---|
| 1020 | S = -g * eta[k]**2 * sqrt((uh[k]**2 + vh[k]**2)) |
---|
| 1021 | S /= h[k]**(7.0/3) |
---|
| 1022 | |
---|
| 1023 | #Update momentum |
---|
| 1024 | xmom_update[k] += S*uh[k] |
---|
| 1025 | ymom_update[k] += S*vh[k] |
---|
| 1026 | |
---|
| 1027 | |
---|
| 1028 | def manning_friction_c(domain): |
---|
| 1029 | """Wrapper for c version |
---|
| 1030 | """ |
---|
| 1031 | |
---|
| 1032 | xmom = domain.quantities['xmomentum'] |
---|
| 1033 | # ymom = domain.quantities['ymomentum'] |
---|
| 1034 | |
---|
| 1035 | w = domain.quantities['stage'].centroid_values |
---|
| 1036 | z = domain.quantities['elevation'].centroid_values |
---|
| 1037 | |
---|
| 1038 | uh = xmom.centroid_values |
---|
| 1039 | # vh = ymom.centroid_values |
---|
| 1040 | eta = domain.quantities['friction'].centroid_values |
---|
| 1041 | |
---|
| 1042 | xmom_update = xmom.semi_implicit_update |
---|
| 1043 | # ymom_update = ymom.semi_implicit_update |
---|
| 1044 | |
---|
| 1045 | N = domain.number_of_elements |
---|
| 1046 | eps = domain.minimum_allowed_height |
---|
| 1047 | g = domain.g |
---|
| 1048 | |
---|
| 1049 | from shallow_water_ext import manning_friction |
---|
| 1050 | # manning_friction(g, eps, w, z, uh, vh, eta, xmom_update, ymom_update) |
---|
| 1051 | manning_friction(g, eps, w, z, uh, eta, xmom_update) |
---|
| 1052 | |
---|
| 1053 | def linear_friction(domain): |
---|
| 1054 | """Apply linear friction to water momentum |
---|
| 1055 | |
---|
| 1056 | Assumes quantity: 'linear_friction' to be present |
---|
| 1057 | """ |
---|
| 1058 | |
---|
| 1059 | from math import sqrt |
---|
| 1060 | |
---|
| 1061 | w = domain.quantities['stage'].centroid_values |
---|
| 1062 | z = domain.quantities['elevation'].centroid_values |
---|
| 1063 | h = w-z |
---|
| 1064 | |
---|
| 1065 | uh = domain.quantities['xmomentum'].centroid_values |
---|
| 1066 | # vh = domain.quantities['ymomentum'].centroid_values |
---|
| 1067 | tau = domain.quantities['linear_friction'].centroid_values |
---|
| 1068 | |
---|
| 1069 | xmom_update = domain.quantities['xmomentum'].semi_implicit_update |
---|
| 1070 | # ymom_update = domain.quantities['ymomentum'].semi_implicit_update |
---|
| 1071 | |
---|
| 1072 | N = domain.number_of_elements |
---|
| 1073 | eps = domain.minimum_allowed_height |
---|
| 1074 | g = domain.g #Not necessary? Why was this added? |
---|
| 1075 | |
---|
| 1076 | for k in range(N): |
---|
| 1077 | if tau[k] >= eps: |
---|
| 1078 | if h[k] >= eps: |
---|
| 1079 | S = -tau[k]/h[k] |
---|
| 1080 | |
---|
| 1081 | #Update momentum |
---|
| 1082 | xmom_update[k] += S*uh[k] |
---|
| 1083 | # ymom_update[k] += S*vh[k] |
---|
| 1084 | |
---|
| 1085 | |
---|
| 1086 | |
---|
| 1087 | def check_forcefield(f): |
---|
| 1088 | """Check that f is either |
---|
| 1089 | 1: a callable object f(t,x,y), where x and y are vectors |
---|
| 1090 | and that it returns an array or a list of same length |
---|
| 1091 | as x and y |
---|
| 1092 | 2: a scalar |
---|
| 1093 | """ |
---|
| 1094 | |
---|
| 1095 | from Numeric import ones, Float, array |
---|
| 1096 | |
---|
| 1097 | |
---|
| 1098 | if callable(f): |
---|
| 1099 | #N = 3 |
---|
| 1100 | N = 2 |
---|
| 1101 | #x = ones(3, Float) |
---|
| 1102 | #y = ones(3, Float) |
---|
| 1103 | x = ones(2, Float) |
---|
| 1104 | y = ones(2, Float) |
---|
| 1105 | |
---|
| 1106 | try: |
---|
| 1107 | #q = f(1.0, x=x, y=y) |
---|
| 1108 | q = f(1.0, x=x) |
---|
| 1109 | except Exception, e: |
---|
| 1110 | msg = 'Function %s could not be executed:\n%s' %(f, e) |
---|
| 1111 | #FIXME: Reconsider this semantics |
---|
| 1112 | raise msg |
---|
| 1113 | |
---|
| 1114 | try: |
---|
| 1115 | q = array(q).astype(Float) |
---|
| 1116 | except: |
---|
| 1117 | msg = 'Return value from vector function %s could ' %f |
---|
| 1118 | msg += 'not be converted into a Numeric array of floats.\n' |
---|
| 1119 | msg += 'Specified function should return either list or array.' |
---|
| 1120 | raise msg |
---|
| 1121 | |
---|
| 1122 | #Is this really what we want? |
---|
| 1123 | msg = 'Return vector from function %s ' %f |
---|
| 1124 | msg += 'must have same lenght as input vectors' |
---|
| 1125 | assert len(q) == N, msg |
---|
| 1126 | |
---|
| 1127 | else: |
---|
| 1128 | try: |
---|
| 1129 | f = float(f) |
---|
| 1130 | except: |
---|
| 1131 | msg = 'Force field %s must be either a scalar' %f |
---|
| 1132 | msg += ' or a vector function' |
---|
| 1133 | raise msg |
---|
| 1134 | return f |
---|