From dc09101e5ccc74c93b701bfdd8c9e12829bb380d Mon Sep 17 00:00:00 2001
From: benSepanski <ben_sepanski@alumni.baylor.edu>
Date: Mon, 6 Jul 2020 17:00:49 -0500
Subject: [PATCH] Update flip_matrix so that can produce arbitrary permutation
---
meshmode/mesh/processing.py | 29 ++++++++++++++++++++---------
1 file changed, 20 insertions(+), 9 deletions(-)
diff --git a/meshmode/mesh/processing.py b/meshmode/mesh/processing.py
index 70c17461..39fe5677 100644
--- a/meshmode/mesh/processing.py
+++ b/meshmode/mesh/processing.py
@@ -365,18 +365,25 @@ def test_volume_mesh_element_orientations(mesh):
# {{{ flips
-def get_simplex_element_flip_matrix(order, unit_nodes):
+def get_simplex_element_flip_matrix(order, unit_nodes, permutation=None):
"""
- Generate a resampling matrix that corresponds to the
- first two barycentric coordinates being swapped.
+ Generate a resampling matrix that corresponds to a
+ permutation of the barycentric coordinates being applied.
+ The default permutation is to swap the
+ first two barycentric coordinates.
:param order: The order of the function space on the simplex,
(see second argument in
:fun:`modepy.simplex_best_available_basis`)
:param unit_nodes: A np array of unit nodes with shape
*(dim, nunit_nodes)*
+ :param permutation: Either *None*, or a tuple of shape
+ storing a permutation:
+ the *i*th barycentric coordinate gets mapped to
+ the *permutation[i]*th coordinate.
- :return: A numpy array of shape *(dim, dim)* which, when applied
+ :return: A numpy array of shape *(nunit_nodes, nunit_nodes)*
+ which, when applied
to the matrix of nodes (shaped *(dim, nunit_nodes)*)
corresponds to the first two barycentric coordinates
being swapped
@@ -386,8 +393,11 @@ def get_simplex_element_flip_matrix(order, unit_nodes):
bary_unit_nodes = unit_to_barycentric(unit_nodes)
flipped_bary_unit_nodes = bary_unit_nodes.copy()
- flipped_bary_unit_nodes[0, :] = bary_unit_nodes[1, :]
- flipped_bary_unit_nodes[1, :] = bary_unit_nodes[0, :]
+ if permutation is None:
+ flipped_bary_unit_nodes[0, :] = bary_unit_nodes[1, :]
+ flipped_bary_unit_nodes[1, :] = bary_unit_nodes[0, :]
+ else:
+ flipped_bary_unit_nodes[:] = bary_unit_nodes[permutation, :]
flipped_unit_nodes = barycentric_to_unit(flipped_bary_unit_nodes)
dim = unit_nodes.shape[0]
@@ -398,9 +408,10 @@ def get_simplex_element_flip_matrix(order, unit_nodes):
flip_matrix[np.abs(flip_matrix) < 1e-15] = 0
# Flipping twice should be the identity
- assert la.norm(
- np.dot(flip_matrix, flip_matrix)
- - np.eye(len(flip_matrix))) < 1e-13
+ if permutation is None:
+ assert la.norm(
+ np.dot(flip_matrix, flip_matrix)
+ - np.eye(len(flip_matrix))) < 1e-13
return flip_matrix
--
GitLab