Fixed database typo and removed unnecessary class identifier.

venv/Lib/site-packages/scipy/ndimage/tests/test_splines.py

@@ -0,0 +1,65 @@
+"""Tests for spline filtering."""
+import numpy as np
+import pytest
+
+from numpy.testing import assert_almost_equal
+
+from scipy import ndimage
+
+
+def get_spline_knot_values(order):
+    """Knot values to the right of a B-spline's center."""
+    knot_values = {0: [1],
+                   1: [1],
+                   2: [6, 1],
+                   3: [4, 1],
+                   4: [230, 76, 1],
+                   5: [66, 26, 1]}
+
+    return knot_values[order]
+
+
+def make_spline_knot_matrix(n, order, mode='mirror'):
+    """Matrix to invert to find the spline coefficients."""
+    knot_values = get_spline_knot_values(order)
+
+    matrix = np.zeros((n, n))
+    for diag, knot_value in enumerate(knot_values):
+        indices = np.arange(diag, n)
+        if diag == 0:
+            matrix[indices, indices] = knot_value
+        else:
+            matrix[indices, indices - diag] = knot_value
+            matrix[indices - diag, indices] = knot_value
+
+    knot_values_sum = knot_values[0] + 2 * sum(knot_values[1:])
+
+    if mode == 'mirror':
+        start, step = 1, 1
+    elif mode == 'reflect':
+        start, step = 0, 1
+    elif mode == 'wrap':
+        start, step = -1, -1
+    else:
+        raise ValueError('unsupported mode {}'.format(mode))
+
+    for row in range(len(knot_values) - 1):
+        for idx, knot_value in enumerate(knot_values[row + 1:]):
+            matrix[row, start + step*idx] += knot_value
+            matrix[-row - 1, -start - 1 - step*idx] += knot_value
+
+    return matrix / knot_values_sum
+
+
+@pytest.mark.parametrize('order', [0, 1, 2, 3, 4, 5])
+@pytest.mark.parametrize('mode', ['mirror', 'wrap', 'reflect'])
+def test_spline_filter_vs_matrix_solution(order, mode):
+    n = 100
+    eye = np.eye(n, dtype=float)
+    spline_filter_axis_0 = ndimage.spline_filter1d(eye, axis=0, order=order,
+                                                   mode=mode)
+    spline_filter_axis_1 = ndimage.spline_filter1d(eye, axis=1, order=order,
+                                                   mode=mode)
+    matrix = make_spline_knot_matrix(n, order, mode=mode)
+    assert_almost_equal(eye, np.dot(spline_filter_axis_0, matrix))
+    assert_almost_equal(eye, np.dot(spline_filter_axis_1, matrix.T))