feat: Initialize FitRecipe with a results file or object

news/init-w-results.rst

@@ -0,0 +1,23 @@
+**Added:**
+
+* Added ``initialize_recipe_with_results`` to ``FitRecipe``.
+
+**Changed:**
+
+* <news item>
+
+**Deprecated:**
+
+* <news item>
+
+**Removed:**
+
+* <news item>
+
+**Fixed:**
+
+* <news item>
+
+**Security:**
+
+* <news item>

src/diffpy/srfit/fitbase/fitrecipe.py

@@ -35,11 +35,13 @@
 __all__ = ["FitRecipe"]
 
 from collections import OrderedDict
+from pathlib import Path
 
 import matplotlib.pyplot as plt
 from bg_mpl_stylesheets.styles import all_styles
 from numpy import array, concatenate, dot, sqrt
 
+import diffpy.srfit.util.inpututils as utils
 from diffpy.srfit.fitbase.fithook import PrintFitHook
 from diffpy.srfit.fitbase.parameter import ParameterProxy
 from diffpy.srfit.fitbase.recipeorganizer import RecipeOrganizer
@@ -1184,6 +1186,74 @@ def initialize_recipe_with_recipe(self, recipe_object):
             if restraint not in self._restraints:
                 self._restraints.add(restraint)
 
+    def _pretty_print_results_dict(self, params_dict):
+        """Pretty print a dictionary of parameter names and values."""
+        sorted_params = sorted(params_dict.items())
+        width = max(len(name) for name, _ in sorted_params)
+        for name, value in sorted_params:
+            if isinstance(value, float):
+                value_str = f"{value:.6g}"
+            else:
+                value_str = str(value)
+            print(f"  {name:<{width}} = {value_str}")
+
+    def _set_parameters_from_dict(self, params_dict):
+        """Set the parameters of the FitRecipe from a dictionary of
+        parameter names and values."""
+        for param_name, param_value in params_dict.items():
+            if param_name in self._parameters:
+                self._parameters[param_name].setValue(param_value)
+            else:
+                print(
+                    f"Warning: Parameter '{param_name}' from results "
+                    "not found in FitRecipe and will be ignored."
+                )
+
+    def initialize_recipe_with_results(self, results, verbose=True):
+        """Initialize a FitRecipe with a FitResults object or a results
+        file.
+
+        Note that at least one FitContribution must already exist in
+        the FitRecipe.
+
+        Parameters
+        ----------
+        results : FitResults, pathlib.Path, or str
+            The FitResults object or path to results file to initialize with.
+        verbose : bool, optional
+            If True, print warnings for any parameters in the results that are
+            not in the FitRecipe. Default is True.
+
+        Raises
+        ------
+        ValueError
+            If the input results is not a FitResults object or a path to a
+            results file.
+        """
+        if hasattr(results, "print_results"):
+            params_dict = utils.get_dict_from_results_object(results)
+        elif isinstance(results, (str, Path)):
+            params_dict = utils.get_dict_from_results_file(results)
+        else:
+            raise ValueError(
+                "The input results must be a FitResults object or a path to a "
+                f"results file, but got {type(results)}."
+            )
+        self._set_parameters_from_dict(params_dict)
+        if verbose:
+            print()
+            print("Parameters found in Results:")
+            print("=" * 30)
+            self._pretty_print_results_dict(params_dict)
+            print()
+            print("Parameters set in FitRecipe:")
+            print("=" * 30)
+            set_parameters_dict = {
+                param.name: param.getValue()
+                for param in self._parameters.values()
+            }
+            self._pretty_print_results_dict(set_parameters_dict)
+
     def set_plot_defaults(self, **kwargs):
         """Set default plotting options for all future plots.
 

src/diffpy/srfit/util/inpututils.py

@@ -17,6 +17,7 @@
 __all__ = ["inputToString"]
 
 import os.path
+from pathlib import Path
 
 
 def inputToString(input):
@@ -51,4 +52,65 @@ def inputToString(input):
     return inptstr
 
 
+def get_dict_from_results_file(
+    results_filepath: Path | str,
+) -> dict[str, float]:
+    """Get a dictionary of parameter names and values from a results
+    file.
+
+    The file should have lines in the format:
+    "parameter_name value +/- uncertainty". Lines that do not match this
+    format will be ignored.
+
+    Parameters
+    ----------
+    results_filepath : pathlib.Path or str
+        The path to the results file.
+
+    Returns
+    -------
+    parsed_results_dict : dict
+        The dictionary where keys are parameter names and values are the
+        corresponding parameter values as floats.
+    """
+    with open(results_filepath, "r") as f:
+        results_string = f.read()
+    parsed_results_dict = {}
+    for raw_line in results_string.splitlines():
+        line = raw_line.strip()
+        # skip blank lines and lines that are just dashes
+        if not line or set(line) == {"-"}:
+            continue
+        line_items = line.split()
+        if len(line_items) < 2:
+            continue
+        if len(line_items) >= 4 and line_items[2] == "+/-":
+            try:
+                parsed_results_dict[line_items[0]] = float(line_items[1])
+            except ValueError:
+                pass
+    return parsed_results_dict
+
+
+def get_dict_from_results_object(results_object) -> dict[str, float]:
+    """Get a dictionary of parameter names and values from a FitResults
+    object.
+
+    Parameters
+    ----------
+    results_object : FitResults
+        The FitResults object containing the parameter names and values.
+
+    Returns
+    -------
+    params_dict : dict
+        The dictionary where keys are parameter names and values are the
+        corresponding parameter values as floats.
+    """
+    param_names = results_object.varnames
+    param_vals = results_object.varvals
+    params_dict = dict(zip(param_names, param_vals))
+    return params_dict
+
+
 # End of file

tests/conftest.py

@@ -150,19 +150,23 @@ def _capturestdout(f, *args, **kwargs):
 @pytest.fixture()
 def build_recipe_one_contribution():
     "helper to build a simple recipe"
-    profile = Profile()
-    x = linspace(0, pi, 10)
-    y = sin(x)
-    profile.set_observed_profile(x, y)
-    contribution = FitContribution("c1")
-    contribution.set_profile(profile)
-    contribution.set_equation("amplitude*sin(wave_number*x + phase_shift)")
-    recipe = FitRecipe()
-    recipe.add_contribution(contribution)
-    recipe.add_variable(contribution.amplitude, 1)
-    recipe.add_variable(contribution.wave_number, 1)
-    recipe.add_variable(contribution.phase_shift, 1)
-    return recipe
+
+    def _build_recipe():
+        profile = Profile()
+        x = linspace(0, pi, 10)
+        y = sin(x)
+        profile.set_observed_profile(x, y)
+        contribution = FitContribution("c1")
+        contribution.set_profile(profile)
+        contribution.set_equation("amplitude*sin(wave_number*x + phase_shift)")
+        recipe = FitRecipe()
+        recipe.add_contribution(contribution)
+        recipe.add_variable(contribution.amplitude, 4)
+        recipe.add_variable(contribution.wave_number, 3)
+        recipe.add_variable(contribution.phase_shift, 2)
+        return recipe
+
+    return _build_recipe
 
 
 @pytest.fixture()