def g(x, y):
return cos(2 * pi * x) + sin(2 * pi * y)
m = mesh.read("CarreMedium.msh")
coords = m[0]
elt2verts = m[1]
nbVerts = coords.shape[0]
nbElts = elt2verts.shape[0]
print('nbVerts : {}'.format(nbVerts))
print('nbElts : {}'.format(nbElts))
begVert2Elts, vert2elts = mesh.compvert2elts(elt2verts)
begRows, indCols = fem.comp_skel_csr_mat(elt2verts, (begVert2Elts, vert2elts))
nz = begRows[-1]
print("Number of non zero in sparse matrix : {}".format(nz))
spCoefs = np.zeros((nz, ), np.double)
for iElt in range(nbElts):
iVertices = elt2verts[iElt, :]
crd1 = coords[iVertices[0], :]
crd2 = coords[iVertices[1], :]
crd3 = coords[iVertices[2], :]
matElem = laplacian.comp_eltmat((crd1[0], crd1[1]), (crd2[0], crd2[1]),
(crd3[0], crd3[1]))
fem.add_elt_mat_to_csr_mat((begRows, indCols, spCoefs),
(iVertices, iVertices, matElem))
coords.shape[0]) #this is the inverse map of v_loc2glo
for ind in range(len(v_loc2glo)):
v_glo2loc[v_loc2glo[ind]] = ind
#we give values for e2v_loc
for ie_loc in range(len(ets_loc2glo)):
ie = ets_loc2glo[ie_loc]
e2v_loc[ie_loc, 0] = v_glo2loc[elt2verts[ie, 0]]
e2v_loc[ie_loc, 1] = v_glo2loc[elt2verts[ie, 1]]
e2v_loc[ie_loc, 2] = v_glo2loc[elt2verts[ie, 2]]
#structure for the sparse local matrix
begVert2Elts_loc, vert2elts_loc = mesh.compvert2elts(e2v_loc)
begRows_loc, indCols_loc = fem.comp_skel_csr_mat(
e2v_loc, (begVert2Elts_loc, vert2elts_loc))
nz = begRows_loc[-1]
file.write("\nNumber of non zero in sparse matrix : {}".format(nz))
#number of vertices and number of elements in the local mesh
nbV_loc = len(v_loc2glo)
nbE_loc = e2v_loc.shape[0]
spCoefs = np.zeros((nz, ), np.double) #coefficients of the sparse matrix
#we add elementary matrices, only for each element in the local mesh
for iElt in range(nbE_loc):
iVertices = e2v_loc[iElt, :]
crd1 = coords[v_loc2glo[iVertices[0]], :]
crd2 = coords[v_loc2glo[iVertices[1]], :]
crd3 = coords[v_loc2glo[iVertices[2]], :]