102 lines
2.6 KiB
Python
102 lines
2.6 KiB
Python
from itertools import combinations
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import numpy as np
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from scipy.spatial import KDTree
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from interp.grid import grid
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from interp.grid import cell
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import logging
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log = logging.getLogger('interp')
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THREE_NODE_TRIANGLE = 2
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FOUR_NODE_TET = 4
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EDGES_FOR_FACE_CONNECTIVITY = 2
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EDGES_FOR_VOLUME_CONNECTIVITY = 3
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class ggrid(grid):
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def __init__(self, filename, dimension = 3):
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"""
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construct an interp.grid.grid-compliant grid
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object out of a {2,3}D gmsh file
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"""
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self.dim = dimension
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log.debug("dimension: %d", self.dim)
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gmsh_file = open(filename, 'r')
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gmsh_file.readline() # $MeshFormat
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gmsh_file.readline()
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gmsh_file.readline() # $EndMeshFormat
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gmsh_file.readline() # $Nodes
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node_count = int(gmsh_file.readline())
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self.verts = np.empty((node_count, dimension))
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self.q = np.empty(node_count)
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for i in xrange(node_count):
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cur_line = gmsh_file.readline()
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(index, x,y,z) = cur_line.split()
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index = int(index) - 1
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self.verts[i][0] = float(x)
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self.verts[i][1] = float(y)
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if self.dim == 3:
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self.verts[i][2] = float(z)
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self.tree = KDTree(self.verts)
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# initialize rest of structures about to be populated (cells,
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# cells_for_vert)
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grid.__init__(self)
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gmsh_file.readline() # $EndNodes
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gmsh_file.readline() # $Elements
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# temporary dict used to compute cell connectivity
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neighbors = {}
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element_count = int(gmsh_file.readline())
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for i in xrange(element_count):
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cur_line = gmsh_file.readline()
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cur_line = cur_line.split()
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cur_cell_index, node_type, rest = (int(cur_line[0]),
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int(cur_line[1]),
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[int(j) for j in cur_line[2:]])
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if (node_type == THREE_NODE_TRIANGLE and self.dim == 2) \
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or (node_type == FOUR_NODE_TET and self.dim == 3):
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points_for_cur_cell = [i-1 for i in rest[rest[0]+1:]]
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cur_cell = cell(cur_cell_index)
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for cur_point in points_for_cur_cell:
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self.cells_for_vert[cur_point].append(cur_cell)
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cur_cell.verts = points_for_cur_cell
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self.cells[cur_cell_index] = cur_cell
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edges = [tuple(sorted(i)) for i in combinations(points_for_cur_cell, self.dim)]
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for edge in edges:
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if edge in neighbors:
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neighbors[edge].append(cur_cell_index)
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else:
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neighbors[edge] = [cur_cell_index]
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for k,v in neighbors.iteritems():
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if len(v) > 1:
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self.cells[v[0]].add_neighbor(self.cells[v[1]])
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self.cells[v[1]].add_neighbor(self.cells[v[0]])
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