Ensure no warning or errors when no extrapolation occurs

news/extrap_fix.rst

@@ -0,0 +1,23 @@
+**Added:**
+
+* <news item>
+
+**Changed:**
+
+* <news item>
+
+**Deprecated:**
+
+* <news item>
+
+**Removed:**
+
+* <news item>
+
+**Fixed:**
+
+* Applying a function with no extrapolation no longer produces an error.
+
+**Security:**
+
+* <news item>

pyproject.toml

@@ -11,7 +11,7 @@ authors = [
 maintainers = [
   { name="Simon J.L. Billinge group", email="simon.billinge@gmail.com" },
 ]
-description = "Python package for manipulating and comparing PDF profiles"
+description = "Python package for manipulating and comparing 1D signals."
 keywords = ['diffpy', 'pdf', 'data interpretation']
 readme = "README.rst"
 requires-python = ">=3.11, <3.14"

src/diffpy/morph/morph_io.py

@@ -501,38 +501,39 @@ def tabulate_results(multiple_morph_results):
 def handle_extrapolation_warnings(morph):
     if morph is not None:
         extrapolation_info = morph.extrapolation_info
-        is_extrap_low = extrapolation_info["is_extrap_low"]
-        is_extrap_high = extrapolation_info["is_extrap_high"]
-        cutoff_low = extrapolation_info["cutoff_low"]
-        cutoff_high = extrapolation_info["cutoff_high"]
-
-        if is_extrap_low and is_extrap_high:
-            wmsg = (
-                "Warning: points with grid value below "
-                f"{cutoff_low} and above "
-                f"{cutoff_high} "
-                f"are extrapolated."
-            )
-        elif is_extrap_low:
-            wmsg = (
-                "Warning: points with grid value below "
-                f"{cutoff_low} "
-                f"are extrapolated."
-            )
-        elif is_extrap_high:
-            wmsg = (
-                "Warning: points with grid value above "
-                f"{cutoff_high} "
-                f"are extrapolated."
-            )
-        else:
-            wmsg = None
+        if extrapolation_info is not None:
+            is_extrap_low = extrapolation_info["is_extrap_low"]
+            is_extrap_high = extrapolation_info["is_extrap_high"]
+            cutoff_low = extrapolation_info["cutoff_low"]
+            cutoff_high = extrapolation_info["cutoff_high"]
+
+            if is_extrap_low and is_extrap_high:
+                wmsg = (
+                    "Warning: points with grid value below "
+                    f"{cutoff_low} and above "
+                    f"{cutoff_high} "
+                    f"are extrapolated."
+                )
+            elif is_extrap_low:
+                wmsg = (
+                    "Warning: points with grid value below "
+                    f"{cutoff_low} "
+                    f"are extrapolated."
+                )
+            elif is_extrap_high:
+                wmsg = (
+                    "Warning: points with grid value above "
+                    f"{cutoff_high} "
+                    f"are extrapolated."
+                )
+            else:
+                wmsg = None
 
-        if wmsg:
-            warnings.warn(
-                wmsg,
-                UserWarning,
-            )
+            if wmsg:
+                warnings.warn(
+                    wmsg,
+                    UserWarning,
+                )
 
 
 def handle_check_increase_warning(squeeze_morph):

src/diffpy/morph/morphs/morph.py

@@ -124,6 +124,7 @@ def __init__(self, config=None):
             All configuration variables.
         """
         # declare empty attributes
+        self.extrapolation_info = None
         if config is None:
             config = {}
         self.x_morph_in = None

tests/test_morphshift.py

@@ -105,3 +105,36 @@ def test_morphshift_extrapolate(user_filesystem, capsys, hshift, wmsg_gen):
     )
     with pytest.warns(UserWarning, match=expected_wmsg):
         single_morph(parser, opts, pargs, stdout_flag=False)
+
+
+def test_morphshift_no_warning(user_filesystem):
+    # Apply a shift with no extrapolation
+    # There should be no warning or errors produced
+    x_morph = numpy.linspace(0, 10, 101)
+    y_morph = numpy.sin(x_morph)
+    x_target = x_morph.copy()
+    y_target = y_morph.copy()
+    morphpy.morph_arrays(
+        numpy.array([x_morph, y_morph]).T,
+        numpy.array([x_target, y_target]).T,
+        hshift=0,
+        apply=True,
+    )
+
+    # CLI test
+    morph_file, target_file = create_morph_data_file(
+        user_filesystem / "cwd_dir", x_morph, y_morph, x_target, y_target
+    )
+
+    parser = create_option_parser()
+    (opts, pargs) = parser.parse_args(
+        [
+            "--scale=1",
+            "--hshift=0",
+            f"{morph_file.as_posix()}",
+            f"{target_file.as_posix()}",
+            "--apply",
+            "-n",
+        ]
+    )
+    single_morph(parser, opts, pargs, stdout_flag=False)

tests/test_morphsqueeze.py

@@ -174,6 +174,44 @@ def test_morphsqueeze_extrapolate(user_filesystem, squeeze_coeffs, wmsg_gen):
         single_morph(parser, opts, pargs, stdout_flag=False)
 
 
+def test_morphsqueeze_no_warning(user_filesystem):
+    # Apply a squeeze with no extrapolation
+    # There should be no warning or errors produced
+    squeeze_coeffs = {"a0": 0, "a1": 0}
+    x_morph = np.linspace(0, 10, 101)
+    y_morph = np.sin(x_morph)
+    x_target = x_morph.copy()
+    y_target = y_morph.copy()
+    morph = MorphSqueeze()
+    morph.squeeze = squeeze_coeffs
+    coeffs = [squeeze_coeffs[f"a{i}"] for i in range(len(squeeze_coeffs))]
+    morphpy.morph_arrays(
+        np.array([x_morph, y_morph]).T,
+        np.array([x_target, y_target]).T,
+        squeeze=coeffs,
+        apply=True,
+    )
+
+    # CLI test
+    morph_file, target_file = create_morph_data_file(
+        user_filesystem / "cwd_dir", x_morph, y_morph, x_target, y_target
+    )
+
+    parser = create_option_parser()
+    (opts, pargs) = parser.parse_args(
+        [
+            "--scale=1",
+            "--squeeze",
+            ",".join(map(str, coeffs)),
+            f"{morph_file.as_posix()}",
+            f"{target_file.as_posix()}",
+            "--apply",
+            "-n",
+        ]
+    )
+    single_morph(parser, opts, pargs, stdout_flag=False)
+
+
 def test_non_unique_grid():
     # Test giving morphsqueeze a non-unique grid
     # Expect it to return a unique grid

tests/test_morphstretch.py

@@ -101,16 +101,16 @@ def test_morphshift_extrapolate(user_filesystem, stretch, wmsg_gen):
     y_morph = numpy.sin(x_morph)
     x_target = x_morph.copy()
     y_target = y_morph.copy()
-    with pytest.warns() as w:
+    with pytest.warns() as warning:
         morphpy.morph_arrays(
             numpy.array([x_morph, y_morph]).T,
             numpy.array([x_target, y_target]).T,
             stretch=stretch,
             apply=True,
         )
-        assert len(w) == 1
-        assert w[0].category is UserWarning
-        actual_wmsg = str(w[0].message)
+        assert len(warning) == 1
+        assert warning[0].category is UserWarning
+        actual_wmsg = str(warning[0].message)
     expected_wmsg = wmsg_gen([min(x_morph), max(x_morph)])
     assert actual_wmsg == expected_wmsg
 
@@ -131,3 +131,36 @@ def test_morphshift_extrapolate(user_filesystem, stretch, wmsg_gen):
     )
     with pytest.warns(UserWarning, match=expected_wmsg):
         single_morph(parser, opts, pargs, stdout_flag=False)
+
+
+def test_morphshift_no_warning(user_filesystem):
+    # Apply a stretch with no extrapolation
+    # There should be no warning or errors produced
+    x_morph = numpy.linspace(1, 10, 101)
+    y_morph = numpy.sin(x_morph)
+    x_target = x_morph.copy()
+    y_target = y_morph.copy()
+    morphpy.morph_arrays(
+        numpy.array([x_morph, y_morph]).T,
+        numpy.array([x_target, y_target]).T,
+        stretch=0,
+        apply=True,
+    )
+
+    # CLI test
+    morph_file, target_file = create_morph_data_file(
+        user_filesystem / "cwd_dir", x_morph, y_morph, x_target, y_target
+    )
+
+    parser = create_option_parser()
+    (opts, pargs) = parser.parse_args(
+        [
+            "--scale=1",
+            "--stretch=0",
+            f"{morph_file.as_posix()}",
+            f"{target_file.as_posix()}",
+            "--apply",
+            "-n",
+        ]
+    )
+    single_morph(parser, opts, pargs, stdout_flag=False)