Revert "changed if statement to ternary operator and minor changes in return statement"

This reverts commit a063c33.

Author: smondal13

pyomo/contrib/doe/utils.py

@@ -161,14 +161,11 @@ def update_model_from_suffix(suffix_obj: pyo.Suffix, values):
 
 def check_matrix(mat, check_pos_def=True):
     """
-    Checks that the matrix is square, positive definite, and symmetric.
+    Checks that the Matrix is square, positive definite, and symmetric.
 
     Parameters
     ----------
     mat: 2D numpy array representing the matrix
-    check_pos_def: bool, optional
-        If True, checks if the matrix is positive definite.
-        Default: True.
 
     Returns
     -------
@@ -402,10 +399,11 @@ def compute_correlation_matrix(
     correlation_matrix = covariance_matrix / std_dev_matrix
 
     # Set the index to the variable names if provided,
-    corr_df = (
-        pd.DataFrame(correlation_matrix, index=var_name, columns=var_name)
-        if var_name
-        else correlation_matrix
-    )
+    if var_name is not None:
+        corr_df = pd.DataFrame(correlation_matrix, index=var_name, columns=var_name)
+    else:
+        corr_df = correlation_matrix
 
-    return corr_df.round(significant_digits) if significant_digits else corr_df
+    return (
+        corr_df.round(significant_digits) if significant_digits else correlation_matrix
+    )