update docs and tests

backend/nodes/radial_profile.py

@@ -33,10 +33,13 @@ class RadialProfile:
     FUNCTION = "process"
 
     DESCRIPTION = (
-        "Compute the azimuthally averaged radial profile from a centre point. "
+        "Compute an azimuthally averaged profile around a centre point. "
+        "At each radius, every pixel in the full 360° ring is averaged together, "
+        "so the profile is direction-independent — there is no clockwise/counter-clockwise "
+        "traversal and no start/end point along the ring. "
         "Drag the centre marker on the preview to reposition the profile, "
-        "drag either end marker to change the radius. "
-        "Output x-axis is radius in physical xy units. "
+        "or drag either end marker (both just set the outer radius) to change the extent. "
+        "Output x-axis is radius in physical xy units."
     )
 
     KEYWORDS = ("azimuthal average", "ring average", "circular", "isotropic")

docs/nodes/Radial Profile.md

@@ -1,6 +1,6 @@
 # Radial Profile
 
-Compute the azimuthally averaged radial profile from a centre point. The output x-axis is radius in physical xy units. Equivalent to gwy_data_field_angular_average used by Gwyddion's Radial Profile tool.
+Compute an **azimuthally averaged** profile around a centre point on a DATA_FIELD. At each radius, every pixel in the full 360° ring around the centre is averaged together, so the profile is direction-independent — there is no clockwise/counter-clockwise traversal and no start or end point along the ring. The output is a single 1-D profile: value vs. radius.
 
 ## Inputs
 
@@ -18,11 +18,13 @@ Compute the azimuthally averaged radial profile from a centre point. The output
 
 | Name | Type | Default | Description |
 |------|------|---------|-------------|
-| cx | FLOAT | 0.5 | Centre x position as a fraction of field width (0 = left, 1 = right) |
-| cy | FLOAT | 0.5 | Centre y position as a fraction of field height (0 = top, 1 = bottom) |
 | n_bins | INT | 128 | Number of radial bins (4-4096) |
 
+## Interactive preview
+
+The dashed circle around the centre shows the outer radius used by the profile. Pixels beyond it are not included in the averaging.
+
 ## Notes
 
-- Pixels are assigned to radial bins by Euclidean distance; bins near the centre contain fewer pixels and may be noisier.
+- Pixels are assigned to radial bins by Euclidean distance from the centre; inner bins contain fewer pixels and may be noisier.
 - Physical x-axis units come from the field's si_unit_xy; uncalibrated fields produce pixel-unit radii.

tests/node_tests/radial_profile.py

@@ -11,7 +11,7 @@ def test_radial_profile_constant_field():
     node = RadialProfile()
     field = make_field(data=np.full((64, 64), 2.5))
 
-    result, = node.process(field, cx=0.5, cy=0.5, n_bins=32)
+    result, = node.process(field, n_bins=32, cx=0.5, cy=0.5, ex=1.0, ey=0.5)
     assert isinstance(result, LineData)
     assert len(result.data) == 32
 
@@ -26,7 +26,7 @@ def test_radial_profile_units():
     node = RadialProfile()
     field = make_field()
 
-    result, = node.process(field, cx=0.5, cy=0.5, n_bins=32)
+    result, = node.process(field, n_bins=32, cx=0.5, cy=0.5, ex=1.0, ey=0.5)
     assert result.x_unit == field.si_unit_xy
     assert result.y_unit == field.si_unit_z
 
@@ -38,7 +38,7 @@ def test_radial_profile_x_axis_monotone():
     node = RadialProfile()
     field = make_field()
 
-    result, = node.process(field, cx=0.5, cy=0.5, n_bins=64)
+    result, = node.process(field, n_bins=64, cx=0.5, cy=0.5, ex=1.0, ey=0.5)
     assert result.x_axis[0] >= 0.0
     assert np.all(np.diff(result.x_axis) > 0)
 
@@ -50,7 +50,7 @@ def test_radial_profile_off_centre():
     node = RadialProfile()
     field = make_field(data=np.ones((64, 64)))
 
-    result, = node.process(field, cx=0.0, cy=0.0, n_bins=32)
+    result, = node.process(field, n_bins=32, cx=0.0, cy=0.0, ex=1.0, ey=1.0)
     assert len(result.data) == 32
     finite = result.data[np.isfinite(result.data)]
     assert np.allclose(finite, 1.0, atol=1e-10)
@@ -67,7 +67,7 @@ def test_radial_profile_radial_symmetry():
     data = np.cos(r * np.pi / (xres / 2.0))
     field = make_field(data=data)
 
-    result, = node.process(field, cx=0.5, cy=0.5, n_bins=32)
+    result, = node.process(field, n_bins=32, cx=0.5, cy=0.5, ex=1.0, ey=0.5)
     finite = result.data[np.isfinite(result.data)]
     # The profile should vary (not constant)
     assert np.std(finite) > 0.01
@@ -80,6 +80,25 @@ def test_radial_profile_n_bins():
     field = make_field()
 
     for n in (16, 64, 256):
-        result, = node.process(field, cx=0.5, cy=0.5, n_bins=n)
+        result, = node.process(field, n_bins=n, cx=0.5, cy=0.5, ex=1.0, ey=0.5)
         assert len(result.data) == n
         assert len(result.x_axis) == n
+
+
+def test_radial_profile_radius_controlled_by_endpoint():
+    """The outer radius is set by the distance from (cx,cy) to (ex,ey)."""
+    from backend.nodes.radial_profile import RadialProfile
+
+    node = RadialProfile()
+    field = make_field()
+
+    # End at (1.0, 0.5): radius = 0.5 * xreal
+    short, = node.process(field, n_bins=32, cx=0.5, cy=0.5, ex=1.0, ey=0.5)
+    expected_r_short = 0.5 * field.xreal
+    assert np.isclose(short.x_axis[-1], expected_r_short, rtol=0.05)
+
+    # End at corner: radius = sqrt(xreal^2 + yreal^2) * 0.5 (half-diagonal)
+    diag, = node.process(field, n_bins=32, cx=0.5, cy=0.5, ex=1.0, ey=1.0)
+    expected_r_diag = 0.5 * np.hypot(field.xreal, field.yreal)
+    assert np.isclose(diag.x_axis[-1], expected_r_diag, rtol=0.05)
+    assert diag.x_axis[-1] > short.x_axis[-1]