Fix

[AinurZiga]

Trying Sionna-RT for my research, I noticed strange behavior with wedges/edges and, particularly, a method for swapping edge extremities to orient identical edges in the same way. The problem was, as I understood that some coordinates (for example, r0 and r1) might coincide, but due to numerical issues, one might be larger than another (r0 > r1 yields True).

I changed the code, so comparison for nearly equal values starts before checking what number is larger.

My 1st commit contains an example where I have observed the problem. All edges have equal radii in spherical coordinates - due to numerical issues, r0 > r1 may give True.
My 2nd commit contains changes to the method for swapping edge extremities.

The code snippet which I used to reproduce the problem.

scene = load_scene(sionna.rt.scene.sphere)
num_edges = tf.reduce_sum(tf.cast(scene._solver_paths._is_edge, tf.int32))
num_wedges = scene._solver_paths._wedges_origin.shape[0] - num_edges
print(num_edges, num_wedges)

Expected output/output after the fix: 0 120
Output before the fix: 44 98

Signed-off by: Ainur Ziganshin ainur.ziganshin@tu-ilmenau.de

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