chore: more concise error message

Author: ycexiao

src/diffpy/morph/refine.py

@@ -85,14 +85,12 @@ def _residual(self, pvals):
         rvec = _y_target - _y_morph
         if len(rvec) < len(pvals):
             raise ValueError(
-                f"\nNumber of shared grid points: {len(rvec)}\n"
-                f"Number of parameters: {len(pvals)}\n"
-                "Not enough shared grid points "
-                "between the morphed function and the target function to fit "
-                "the chosen parameters.\n"
-                "Please make sure the overlapping domain between the morphed "
-                "function and the target function is sufficiently large, or "
-                "reduce the number of parameters."
+                f"\nNumber of parameters (currently {len(pvals)}) cannot "
+                "exceed the number of shared grid points "
+                f"(currently {len(rvec)}). "
+                "Please reduce the number of morphing parameters or "
+                "provide new morphing and target functions with more "
+                "shared grid points."
             )
         # If first time computing residual
         if self.res_length is None:

tests/test_refine.py

@@ -194,14 +194,12 @@ def test_refine_grid_bad(self, user_filesystem):
         refiner = Refiner(chain, grid1, func1, grid2, func2)
         refpars = ["stretch", "scale", "smear"]
         expected_error_message = (
-            "\nNumber of shared grid points: 2\n"
-            "Number of parameters: 3\n"
-            "Not enough shared grid points "
-            "between the morphed function and the target function to fit "
-            "the chosen parameters.\n"
-            "Please make sure the overlapping domain between the morphed "
-            "function and the target function is sufficiently large, or "
-            "reduce the number of parameters."
+            f"\nNumber of parameters (currently 3) cannot "
+            "exceed the number of shared grid points "
+            f"(currently 2). "
+            "Please reduce the number of morphing parameters or "
+            "provide new morphing and target functions with more "
+            "shared grid points."
         )
         with pytest.raises(
             ValueError,