test: add test fro sequential_cmi_runner

docs/examples/sequential_fit_example.py

@@ -32,4 +32,10 @@
     plot_variable_names=["a_1"],
     plot_result_entry_names=["residual"],
 )
+sts.set_start_input_file(
+    "Ni_PDF_20250922-222655_ca8ae7_14K.gr",
+    input_filename_to_result_filename=lambda input_filename: input_filename.replace(  # noqa E501
+        ".gr", "_result.json"
+    ),
+)
 sts.run(mode="stream")

news/runner-test.rst

@@ -0,0 +1,23 @@
+**Added:**
+
+* No news added: Added test for ``sequential_cmi_runner``.
+
+**Changed:**
+
+* <news item>
+
+**Deprecated:**
+
+* <news item>
+
+**Removed:**
+
+* <news item>
+
+**Fixed:**
+
+* <news item>
+
+**Security:**
+
+* <news item>

src/pdfbl/sequential/pdfadapter.py

@@ -14,7 +14,7 @@
 from diffpy.srfit.pdf import PDFGenerator, PDFParser
 from diffpy.srfit.structure import constrainAsSpaceGroup
 from diffpy.structure.parsers import getParser
-from scipy.optimize import minimize
+from scipy.optimize import least_squares
 
 
 class PDFAdapter:
@@ -276,11 +276,19 @@ def refine_variables(self, variable_names: list[str]):
         variable_names : list of str
             The names of the variables to refine.
         """
+        for vname in variable_names:
+            if vname not in self.recipe._parameters:
+                raise ValueError(
+                    f"Variable {vname} not found in the recipe. "
+                    "Please choose from the existing variables: "
+                    f"{list(self.recipe._parameters.keys())}"
+                )
         for vname in variable_names:
             self.recipe.free(vname)
-            minimize(
-                self.recipe.scalarResidual,
+            least_squares(
+                self.recipe.residual,
                 self.recipe.values,
+                x_scale="jac",
             )
 
     def get_variable_names(self) -> list[str]: