[7913] | 1 | // Python - C extension for finite_volumes util module. |
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| 2 | // |
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| 3 | // To compile (Python2.3): |
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| 4 | // gcc -c util_ext.c -I/usr/include/python2.3 -o util_ext.o -Wall -O |
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| 5 | // gcc -shared util_ext.o -o util_ext.so |
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| 6 | // |
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| 7 | // See the module util.py |
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| 8 | // |
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| 9 | // |
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| 10 | // Ole Nielsen, GA 2004 |
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| 11 | |
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| 12 | #include "Python.h" |
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| 13 | #include "Numeric/arrayobject.h" |
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| 14 | #include "math.h" |
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| 15 | |
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| 16 | |
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| 17 | double max(double x, double y) { |
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| 18 | //Return maximum of two doubles |
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| 19 | |
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| 20 | if (x > y) return x; |
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| 21 | else return y; |
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| 22 | } |
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| 23 | |
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| 24 | |
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| 25 | double min(double x, double y) { |
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| 26 | //Return minimum of two doubles |
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| 27 | |
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| 28 | if (x < y) return x; |
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| 29 | else return y; |
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| 30 | } |
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| 31 | |
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| 32 | |
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| 33 | int _gradient(double x0, double y0, |
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| 34 | double x1, double y1, |
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| 35 | double x2, double y2, |
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| 36 | double q0, double q1, double q2, |
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| 37 | double *a, double *b) { |
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| 38 | |
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| 39 | /*Compute gradient (a,b) based on three points (x0,y0), (x1,y1) and (x2,y2) |
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| 40 | with values q0, q1 and q2. |
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| 41 | |
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| 42 | Extrapolation formula (q0 is selected as an arbitrary origin) |
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| 43 | q(x,y) = q0 + a*(x-x0) + b*(y-y0) (1) |
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| 44 | |
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| 45 | Substituting the known values for q1 and q2 into (1) yield the |
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| 46 | equations for a and b |
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| 47 | |
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| 48 | q1-q0 = a*(x1-x0) + b*(y1-y0) (2) |
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| 49 | q2-q0 = a*(x2-x0) + b*(y2-y0) (3) |
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| 50 | |
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| 51 | or in matrix form |
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| 52 | |
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| 53 | / \ / \ / \ |
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| 54 | | x1-x0 y1-y0 | | a | | q1-q0 | |
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| 55 | | | | | = | | |
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| 56 | | x2-x0 y2-y0 | | b | | q2-q0 | |
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| 57 | \ / \ / \ / |
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| 58 | |
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| 59 | which is solved using the standard determinant technique |
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| 60 | |
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| 61 | */ |
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| 62 | |
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| 63 | |
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| 64 | double det; |
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| 65 | |
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| 66 | det = (y2-y0)*(x1-x0) - (y1-y0)*(x2-x0); |
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| 67 | |
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| 68 | *a = (y2-y0)*(q1-q0) - (y1-y0)*(q2-q0); |
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| 69 | *a /= det; |
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| 70 | |
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| 71 | *b = (x1-x0)*(q2-q0) - (x2-x0)*(q1-q0); |
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| 72 | *b /= det; |
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| 73 | |
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| 74 | return 0; |
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| 75 | } |
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| 76 | |
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| 77 | |
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| 78 | int _gradient2(double x0, double y0, |
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| 79 | double x1, double y1, |
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| 80 | double q0, double q1, |
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| 81 | double *a, double *b) { |
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| 82 | /*Compute gradient (a,b) between two points (x0,y0) and (x1,y1) |
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| 83 | with values q0 and q1 such that the plane is constant in the direction |
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| 84 | orthogonal to (x1-x0, y1-y0). |
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| 85 | |
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| 86 | Extrapolation formula |
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| 87 | q(x,y) = q0 + a*(x-x0) + b*(y-y0) (1) |
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| 88 | |
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| 89 | Substituting the known values for q1 into (1) yields an |
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| 90 | under determined equation for a and b |
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| 91 | q1-q0 = a*(x1-x0) + b*(y1-y0) (2) |
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| 92 | |
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| 93 | |
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| 94 | Now add the additional requirement that the gradient in the direction |
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| 95 | orthogonal to (x1-x0, y1-y0) should be zero. The orthogonal direction |
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| 96 | is given by the vector (y0-y1, x1-x0). |
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| 97 | |
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| 98 | Define the point (x2, y2) = (x0 + y0-y1, y0 + x1-x0) on the orthognal line. |
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| 99 | Then we know that the corresponding value q2 should be equal to q0 in order |
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| 100 | to obtain the zero gradient, hence applying (1) again |
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| 101 | q0 = q2 = q(x2, y2) = q0 + a*(x2-x0) + b*(y2-y0) |
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| 102 | = q0 + a*(x0 + y0-y1-x0) + b*(y0 + x1-x0 - y0) |
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| 103 | = q0 + a*(y0-y1) + b*(x1-x0) |
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| 104 | |
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| 105 | leads to the orthogonality constraint |
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| 106 | a*(y0-y1) + b*(x1-x0) = 0 (3) |
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| 107 | |
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| 108 | which closes the system and yields |
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| 109 | |
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| 110 | / \ / \ / \ |
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| 111 | | x1-x0 y1-y0 | | a | | q1-q0 | |
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| 112 | | | | | = | | |
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| 113 | | y0-y1 x1-x0 | | b | | 0 | |
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| 114 | \ / \ / \ / |
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| 115 | |
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| 116 | which is solved using the standard determinant technique |
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| 117 | |
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| 118 | */ |
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| 119 | |
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| 120 | double det, xx, yy, qq; |
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| 121 | |
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| 122 | xx = x1-x0; |
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| 123 | yy = y1-y0; |
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| 124 | qq = q1-q0; |
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| 125 | |
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| 126 | det = xx*xx + yy*yy; //FIXME catch det == 0 |
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| 127 | *a = xx*qq/det; |
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| 128 | *b = yy*qq/det; |
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| 129 | |
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| 130 | return 0; |
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| 131 | } |
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| 132 | |
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| 133 | |
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| 134 | void _limit_old(int N, double beta, double* qc, double* qv, |
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| 135 | double* qmin, double* qmax) { |
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| 136 | |
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| 137 | //N are the number of elements |
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| 138 | int k, i, k3; |
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| 139 | double dq, dqa[3], phi, r; |
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| 140 | |
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| 141 | //printf("INSIDE\n"); |
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| 142 | for (k=0; k<N; k++) { |
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| 143 | k3 = k*3; |
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| 144 | |
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| 145 | //Find the gradient limiter (phi) across vertices |
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| 146 | phi = 1.0; |
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| 147 | for (i=0; i<3; i++) { |
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| 148 | r = 1.0; |
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| 149 | |
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| 150 | dq = qv[k3+i] - qc[k]; //Delta between vertex and centroid values |
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| 151 | dqa[i] = dq; //Save dq for use in the next loop |
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| 152 | |
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| 153 | if (dq > 0.0) r = (qmax[k] - qc[k])/dq; |
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| 154 | if (dq < 0.0) r = (qmin[k] - qc[k])/dq; |
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| 155 | |
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| 156 | |
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| 157 | phi = min( min(r*beta, 1.0), phi); |
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| 158 | } |
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| 159 | |
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| 160 | //Then update using phi limiter |
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| 161 | for (i=0; i<3; i++) { |
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| 162 | qv[k3+i] = qc[k] + phi*dqa[i]; |
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| 163 | } |
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| 164 | } |
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| 165 | } |
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| 166 | |
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| 167 | |
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| 168 | void print_double_array(char* name, double* array, int n, int m){ |
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| 169 | |
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| 170 | int k,i,km; |
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| 171 | |
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| 172 | printf("%s = [",name); |
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| 173 | for (k=0; k<n; k++){ |
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| 174 | km = m*k; |
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| 175 | printf("["); |
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| 176 | for (i=0; i<m ; i++){ |
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| 177 | printf("%g ",array[km+i]); |
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| 178 | } |
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| 179 | if (k==(n-1)) |
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| 180 | printf("]"); |
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| 181 | else |
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| 182 | printf("]\n"); |
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| 183 | } |
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| 184 | printf("]\n"); |
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| 185 | } |
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| 186 | |
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| 187 | void print_int_array(char* name, int* array, int n, int m){ |
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| 188 | |
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| 189 | int k,i,km; |
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| 190 | |
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| 191 | printf("%s = [",name); |
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| 192 | for (k=0; k<n; k++){ |
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| 193 | km = m*k; |
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| 194 | printf("["); |
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| 195 | for (i=0; i<m ; i++){ |
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| 196 | printf("%i ",array[km+i]); |
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| 197 | } |
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| 198 | if (k==(n-1)) |
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| 199 | printf("]"); |
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| 200 | else |
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| 201 | printf("]\n"); |
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| 202 | } |
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| 203 | printf("]\n"); |
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| 204 | } |
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| 205 | |
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| 206 | |
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| 207 | void print_long_array(char* name, long* array, int n, int m){ |
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| 208 | |
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| 209 | int k,i,km; |
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| 210 | |
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| 211 | printf("%s = [",name); |
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| 212 | for (k=0; k<n; k++){ |
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| 213 | km = m*k; |
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| 214 | printf("["); |
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| 215 | for (i=0; i<m ; i++){ |
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| 216 | printf("%i ",(int) array[km+i]); |
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| 217 | } |
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| 218 | if (k==(n-1)) |
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| 219 | printf("]"); |
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| 220 | else |
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| 221 | printf("]\n"); |
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| 222 | } |
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| 223 | printf("]\n"); |
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| 224 | } |
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| 225 | |
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| 226 | void print_numeric_array(PyArrayObject *x) { |
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| 227 | int i, j; |
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| 228 | for (i=0; i<x->dimensions[0]; i++) { |
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| 229 | for (j=0; j<x->dimensions[1]; j++) { |
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| 230 | printf("%f ", *(double*) (x->data + i*x->strides[0] + j*x->strides[1])); |
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| 231 | } |
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| 232 | printf("\n"); |
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| 233 | } |
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| 234 | printf("\n"); |
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| 235 | } |
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| 236 | |
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| 237 | void print_numeric_vector(PyArrayObject *x) { |
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| 238 | int i; |
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| 239 | for (i=0; i<x->dimensions[0]; i++) { |
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| 240 | printf("%f ", *(double*) (x->data + i*x->strides[0])); |
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| 241 | } |
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| 242 | printf("\n"); |
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| 243 | } |
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| 244 | |
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| 245 | PyArrayObject *get_consecutive_array(PyObject *O, char *name) { |
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| 246 | PyArrayObject *A, *B; |
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| 247 | |
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| 248 | |
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| 249 | //Get array object from attribute |
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| 250 | |
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| 251 | /* |
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| 252 | //FIXME: THE TEST DOESN't WORK |
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| 253 | printf("Err = %d\n", PyObject_HasAttrString(O, name)); |
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| 254 | if (PyObject_HasAttrString(O, name) == 1) { |
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| 255 | B = (PyArrayObject*) PyObject_GetAttrString(O, name); |
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| 256 | if (!B) return NULL; |
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| 257 | } else { |
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| 258 | return NULL; |
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| 259 | } |
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| 260 | */ |
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| 261 | |
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| 262 | B = (PyArrayObject*) PyObject_GetAttrString(O, name); |
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| 263 | |
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| 264 | //printf("B = %p\n",(void*)B); |
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| 265 | if (!B) { |
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| 266 | printf("util_ext.h: get_consecutive_array could not obtain python object"); |
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| 267 | printf(" %s\n",name); |
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| 268 | fflush(stdout); |
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| 269 | PyErr_SetString(PyExc_RuntimeError, "util_ext.h: get_consecutive_array could not obtain python object"); |
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| 270 | return NULL; |
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| 271 | } |
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| 272 | |
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| 273 | //Convert to consecutive array |
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| 274 | A = (PyArrayObject*) PyArray_ContiguousFromObject((PyObject*) B, |
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| 275 | B -> descr -> type, 0, 0); |
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| 276 | |
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| 277 | Py_DECREF(B); //FIXME: Is this really needed?? |
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| 278 | |
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| 279 | if (!A) { |
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| 280 | printf("util_ext.h: get_consecutive_array could not obtain array object"); |
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| 281 | printf(" %s \n",name); |
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| 282 | fflush(stdout); |
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| 283 | PyErr_SetString(PyExc_RuntimeError, "util_ext.h: get_consecutive_array could not obtain array"); |
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| 284 | return NULL; |
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| 285 | } |
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| 286 | |
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| 287 | |
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| 288 | return A; |
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| 289 | } |
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| 290 | |
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| 291 | |
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| 292 | |
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| 293 | double get_python_double(PyObject *O, char *name) { |
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| 294 | PyObject *TObject; |
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| 295 | #define BUFFER_SIZE 80 |
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| 296 | char buf[BUFFER_SIZE]; |
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| 297 | double tmp; |
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| 298 | int n; |
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| 299 | |
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| 300 | |
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| 301 | //Get double from attribute |
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| 302 | TObject = PyObject_GetAttrString(O, name); |
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| 303 | if (!TObject) { |
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| 304 | n = snprintf(buf, BUFFER_SIZE, "util_ext.h: get_python_double could not obtain double %s.\n", name); |
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| 305 | //printf("name = %s",name); |
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| 306 | PyErr_SetString(PyExc_RuntimeError, buf); |
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| 307 | |
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| 308 | return 0.0; |
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| 309 | } |
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| 310 | |
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| 311 | tmp = PyFloat_AsDouble(TObject); |
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| 312 | |
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| 313 | Py_DECREF(TObject); |
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| 314 | |
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| 315 | return tmp; |
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| 316 | } |
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| 317 | |
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| 318 | |
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| 319 | |
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| 320 | |
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| 321 | int get_python_integer(PyObject *O, char *name) { |
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| 322 | PyObject *TObject; |
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| 323 | #define BUFFER_SIZE 80 |
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| 324 | char buf[BUFFER_SIZE]; |
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| 325 | long tmp; |
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| 326 | int n; |
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| 327 | |
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| 328 | |
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| 329 | //Get double from attribute |
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| 330 | TObject = PyObject_GetAttrString(O, name); |
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| 331 | if (!TObject) { |
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| 332 | n = snprintf(buf, BUFFER_SIZE, "util_ext.h: get_python_integer could not obtain double %s.\n", name); |
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| 333 | //printf("name = %s",name); |
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| 334 | PyErr_SetString(PyExc_RuntimeError, buf); |
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| 335 | return 0; |
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| 336 | } |
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| 337 | |
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| 338 | tmp = PyInt_AsLong(TObject); |
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| 339 | |
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| 340 | Py_DECREF(TObject); |
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| 341 | |
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| 342 | return tmp; |
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| 343 | } |
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| 344 | |
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| 345 | |
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| 346 | PyObject *get_python_object(PyObject *O, char *name) { |
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| 347 | PyObject *Oout; |
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| 348 | |
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| 349 | Oout = PyObject_GetAttrString(O, name); |
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| 350 | if (!Oout) { |
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| 351 | PyErr_SetString(PyExc_RuntimeError, "util_ext.h: get_python_object could not obtain object"); |
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| 352 | return NULL; |
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| 353 | } |
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| 354 | |
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| 355 | return Oout; |
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| 356 | |
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| 357 | } |
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| 358 | |
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| 359 | |
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| 360 | |
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