# UniformTriRefiner gives uncorrect results for transposed arrays

Hi, all

The following code repeats the problem. Array ele1 is same as ele2 except that it is transpose of ele0, but the refined triangles using ele1 is incorrect.

The problem is also reported at https://github.com/matplotlib/matplotlib/issues/4180

matplotlib version: 1.4.0, the UniformTriRefiner code in version 1.4.3 is the same as 1.4.0。

#!/bin/env python

import numpy as np

import matplotlib.tri as tri

import matplotlib.pyplot as plt

x = np.array([ 120.39299774, 120.59100342, 120.42900085, 120.31700134])

y = np.array([ 33.99900055, 34.00899887, 34.18799973, 34.18399811])

ele0 = np.array([[2, 2], [0, 1], [3, 0]])

ele1 = ele0.transpose() # ele1 is same as ele2 except that it is transpose of ele0

ele2 = np.array([[2, 0, 3], [2, 1, 0]])

triang1 = tri.Triangulation(x, y, ele1)

triang2 = tri.Triangulation(x, y, ele2)

refiner1 = tri.UniformTriRefiner(triang1)

refiner2 = tri.UniformTriRefiner(triang2)

fine_triang1 = refiner1.refine_triangulation(subdiv=1)

fine_triang2 = refiner2.refine_triangulation(subdiv=1)

fig = plt.figure()

ha1.set_aspect(‘equal’)

plt.triplot(fine_triang1, color=‘b’, linewidth=0.5)

plt.triplot(triang1, color=‘k’, linewidth=1)

plt.title(‘refine_triang1 is incorrect’)

ha2.set_aspect(‘equal’)

plt.triplot(fine_triang2, color=‘b’, linewidth=0.5)

plt.triplot(triang2, color=‘k’, linewidth=1)

plt.title(‘refine_triang2 is correct’)

plt.show()

···

Paul