Updated m(RQ)-fit method implementation

CHANGELOG.md

@@ -31,6 +31,7 @@
 - Updated the `fit_circuit` function to ignore `RuntimeWarning`s during fitting.
 - Updated the `Warburg` element class to include an `n` exponent (fixed at 0.5 by default).
 - Updated the `plot_gamma` function to include a horizontal line marking zero on the y-axis.
+- Updated the automatic adjustment of initial values of circuit parameters to be bypassed when a non-default value is detected in a `Circuit` that is provided to the m(RQ)-fit method without a corresponding `FitResult`.
 - Fixed a bug that caused methods such as `DRTResult.get_peaks` to miss peaks at the time constant extremes.
 - Fixed a bug that caused an element's parameters in `FitResult.to_parameters_dataframe` to not be in a sorted order.
 - Fixed the previously unimplemented `FitResult.get_parameters` method.

src/pyimpspec/analysis/drt/mrq_fit.py

@@ -334,6 +334,16 @@ def _validate_circuit(circuit: Circuit):
 
 
 def _adjust_initial_values(circuit: Circuit, data: DataSet) -> Circuit:
+    element: Union[Element, Connection]
+    for element in circuit.get_elements(recursive=True):
+        defaults: Dict[str, float] = element.get_default_values()
+
+        key: str
+        value: float
+        for key, value in element.get_values().items():
+            if not isclose(value, defaults[key]):
+                return circuit
+
     f: Frequencies = data.get_frequencies()
     Z_exp: ComplexImpedances = data.get_impedances()
 
@@ -342,7 +352,6 @@ def _adjust_initial_values(circuit: Circuit, data: DataSet) -> Circuit:
     if not isinstance(series, Series):
         raise TypeError(f"Expected a Series instead of {series=}")
 
-    element: Union[Element, Connection]
     for element in series:
         if isinstance(element, Resistor):
             if not element.is_fixed("R"):