Fixes for corner cases of `regridding.geometry.two_line_segment_inter…

…section()`.

regridding/geometry.py

@@ -260,7 +260,7 @@ def two_line_segment_intersection_parameters(
  y_q2=y_q2,
  )
  if not bounding_boxes_intersect:
- return math.nan, math.nan, math.nan
+ return math.inf, math.inf, 1
 
  a = line_equation_2d(
  x=x_q1,
@@ -278,8 +278,9 @@ def two_line_segment_intersection_parameters(
  x2=x_p2,
  y2=y_p2,
  )
- if regridding.math.sign(a) == regridding.math.sign(b):
- return math.nan, math.nan, math.nan
+ if (a != 0) and (b != 0):
+ if regridding.math.sign(a) == regridding.math.sign(b):
+ return math.inf, math.inf, 1
 
  c = line_equation_2d(
  x=x_p1,
@@ -297,8 +298,9 @@ def two_line_segment_intersection_parameters(
  x2=x_q2,
  y2=y_q2,
  )
- if regridding.math.sign(c) == regridding.math.sign(d):
- return math.nan, math.nan, math.nan
+ if (c != 0) and (d != 0):
+ if regridding.math.sign(c) == regridding.math.sign(d):
+ return math.inf, math.inf, 1
 
  det = a - b
  sdet = +a

regridding/tests/test_geometry.py

@@ -91,11 +91,15 @@ def test_bounding_boxes_intersect_2d(
 @pytest.mark.parametrize(
  argnames="x_p1,y_p1,x_p2,y_p2,x_q1,y_q1,x_q2,y_q2,sdet_expected,tdet_expected,det_expected",
  argvalues=[
- (0, 0, 1, 1, 2, 0, 3, 1, math.nan, math.nan, math.nan),
- (-1, -1, 0, 0, 1, 0, 0, 1, math.nan, math.nan, math.nan),
- (1, 0, 0, 1, -1, -1, 0, 0, math.nan, math.nan, math.nan),
+ (0, 0, 1, 1, 2, 0, 3, 1, math.inf, math.inf, 1),
+ (-1, -1, 0, 0, 1, 0, 0, 1, math.inf, math.inf, 1),
+ (1, 0, 0, 1, -1, -1, 0, 0, math.inf, math.inf, 1),
  (-1, -1, 1, 1, 1, -1, -1, 1, 4, 4, 8),
  (0, 0, 0, 1, 0, 0, 1, 0, 0, 0, -1),
+ (0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0),
+ (0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0),
+ (0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0),
+ (0, 0, 2, 2, 1, 1, 3, 3, 0, 0, 0),
  ],
 )
 def test_two_line_segment_intersection_parameters(