Changeset 543

Timestamp:

Nov 15, 2004, 3:56:16 PM (19 years ago)

Author:

ole

Message:

Added circular mesh (not suitable for detailed grids, though)

File:

• inundation/ga/storm_surge/pyvolution/mesh_factory.py (modified) (2 diffs)

inundation/ga/storm_surge/pyvolution/mesh_factory.py

@@ -164 +164 @@
 
 
+
+def circular(m, n, radius=1.0, center = (0.0, 0.0)):
+    """Setup a circular grid of triangles with m concentric circles and
+    with n radial segments. If radius is are omitted the mesh defaults to
+    the unit circle radius.
+ 
+    radius: radius of circle
+    
+    #FIXME: The triangles become degenerate for large values of m or n.
+    """
+
+
+    
+    from math import pi, cos, sin
+
+    radius = float(radius) #Ensure floating point format
+
+    #Dictionary of vertex objects and list of points
+    vertices = {}
+    points = [[0.0, 0.0]] #Center point
+    vertices[0, 0] = 0
+    
+    for i in range(n):
+        theta = 2*i*pi/n
+        x = cos(theta)
+        y = sin(theta)
+        for j in range(1,m+1):
+            delta = j*radius/m
+            vertices[i,j] = len(points)
+            points.append([delta*x, delta*y])
+
+    #Construct 2 triangles per element        
+    elements = []
+    for i in range(n):
+        for j in range(1,m):
+
+            i1 = (i + 1) % n  #Wrap around  
+            
+            v1 = vertices[i,j+1]
+            v2 = vertices[i,j]            
+            v3 = vertices[i1,j+1]            
+            v4 = vertices[i1,j]
+
+            elements.append([v4,v2,v3]) #Lower                
+            elements.append([v1,v3,v2]) #Upper
+
+
+    #Do the center
+    v1 = vertices[0,0]
+    for i in range(n):
+        i1 = (i + 1) % n  #Wrap around          
+        v2 = vertices[i,1]
+        v3 = vertices[i1,1]
+
+        elements.append([v1,v2,v3]) #center
+         
+    return points, elements
+
+
 def from_polyfile(name):
     """Read mesh from .poly file, an obj like file format
@@ -335 +394 @@
     return points, elements                             
 
-
-
-#FIXME: These haven't been done yet
-# def circular_mesh(m, n, radius=1.0, center = (0.0, 0.0),  Triangle=Triangle,
-#                   Mesh=Mesh, Point=Point):
-#     """Setup a circular grid of triangles
-#     with m+1 radial segments by n+1 points around the circuference
-#     and radius. If radius is are omitted the mesh defaults to the unit circle
-#     radius.
- 
-#     radius: radius of circle
-
-#     Triangle refers to the actual class or subclass to be instantiated:
-#     e.g. if Volume is a subclass of Triangle,
-#     this function can be invoked with the keywords
-#     rectangular_mesh(...,Triangle=Volume, Mesh=Domain)"""
-    
-
-#     from Numeric import array
-#     from visual import rate
-#     import math
-
-#     delta = radius/float(m)
-
-#     #Dictionary of vertex objects
-#     vertices = {}
-#     for i in range(n+1):
-#         theta = float(i)*(2*math.pi)/float(n)  
-#         for j in range(m+1):
-#             delta = float(j)*radius/float(m)
-#             vertices[i,j] = Point(delta*math.cos(theta),delta*math.sin(theta))
-
-#     #Construct 2 triangles per element        
-#     elements = []
-#     for i in range(n):
-#         for j in range(1,m):
-#             v1 = vertices[i,j+1]
-#             v2 = vertices[i,j]            
-#             v3 = vertices[i+1,j+1]            
-#             v4 = vertices[i+1,j]
-
-#             elements.append(Triangle(v4,v2,v3)) #Lower                
-#             elements.append(Triangle(v1,v3,v2)) #Upper    
-
-#     #Do the center
-#     v1 = vertices[0,0]
-#     for i in range(n):
-#         v2 = vertices[i,1]
-#         v3 = vertices[i+1,1]
-
-#         T = Triangle(v1,v2,v3) #center
-#         elements.append(T)
-
-#     return Mesh(elements)