Small changes to evaluator and expression simplification to make it b…

…etter to use

SRToolkit/evaluation/sr_evaluator.py

@@ -63,6 +63,7 @@ def __init__(
             get_results(top_k): Returns the results of the evaluation.
         """
         self.models = dict()
+        self.invalid = list()
         self.metadata = metadata
         self.symbol_library = symbol_library
         self.max_evaluations = max_evaluations
@@ -116,7 +117,18 @@ def evaluate_expr(self, expr: Union[List[str], Node], simplify_expr=False) -> fl
             return np.nan
         else:
             if simplify_expr:
-                expr = simplify(expr, self.symbol_library)
+                try:
+                    expr = simplify(expr, self.symbol_library)
+                except Exception as e:
+                    if isinstance(expr, Node):
+                        expr_list = expr.to_list(symbol_library=self.symbol_library)
+                    else:
+                        expr_list = expr
+                    print(f"Unable to simplify: {''.join(expr_list)}, problems with subexpression {e}")
+
+                    self.invalid.append(expr_list)
+                    return np.inf
+
 
             if isinstance(expr, Node):
                 expr_list = expr.to_list(symbol_library=self.symbol_library)

SRToolkit/utils/expression_simplifier.py

@@ -2,7 +2,7 @@
 
 import numpy as np
 from sympy import sympify, expand, Expr, Basic
-from sympy.core import Mul, Add, Pow
+from sympy.core import Mul, Add, Pow, Symbol
 from sympy import symbols as sp_symbols
 import re
 
@@ -106,7 +106,7 @@ def _sympy_to_sr(expr: Union[Expr, Basic]) -> Node:
     if expr.is_Rational and expr.q != 1:
         return Node('/', _sympy_to_sr(expr.q), _sympy_to_sr(expr.p))
 
-    raise ValueError(f"Unsupported Sympy expression: {expr}")
+    raise ValueError(f"{expr}")
 
 
 def _simplify_constants(eq, c, var):
@@ -125,8 +125,8 @@ def _simplify_constants(eq, c, var):
     if len(eq.args) == 0:
         if eq in var:
             return True, False, [(eq, eq)]
-        elif str(eq)[0] == str(c):
-            return False, True, [(eq, eq)]
+        elif eq in eq.free_symbols:
+            return False, True, [(eq, c)]
         else:
             return False, False, [(eq, eq)]
     else:
@@ -215,7 +215,8 @@ def _simplify_expression (expr_str, constant, variables):
     expr, _ = _enumerate_constants(expr, constant)
     expr = expand(expr)
     expr = _simplify_constants(expr, c, x)[2][0][1]
-    expr, _ = _enumerate_constants(expr, constant)
+    # expr, _ = _enumerate_constants(expr, constant)
+    # expr = _simplify_constants(expr, c, x)[2][0][1]
     return expr
 
 

examples/SR_evaluation_minimal_example.py

@@ -39,10 +39,14 @@ def read_expressions(filename):
     start_time = time.time()
 
     # Evaluate expressions one by one
-    for expr in expressions:
-        evaluator.evaluate_expr(expr)
+    for i, expr in enumerate(expressions):
+        # print(f"{i}: Expr: {''.join(expr)}")
+        evaluator.evaluate_expr(expr, simplify_expr=True)
 
     print(f"Total time: {time.time() - start_time}")
 
     # Get and print the results
     print(evaluator.get_results())
+
+# Simplified: 396.6958358287811
+# Non simplified: 156.62710046768188