Add more piecewise operators

pysr/export_sympy.py

@@ -47,10 +47,13 @@ sympy_mappings = {
     "ceil": sympy.ceiling,
     "sign": sympy.sign,
     "gamma": sympy.gamma,
+    "round": lambda x: sympy.ceiling(x - 0.5),
     "max": lambda x, y: sympy.Piecewise((y, x < y), (x, True)),
     "min": lambda x, y: sympy.Piecewise((x, x < y), (y, True)),
-    "round": lambda x: sympy.ceiling(x - 0.5),
-    "cond": lambda x, y: sympy.Heaviside(x, H0=0) * y,
+    "cond": lambda x, y: sympy.Piecewise((y, x > 0), (0.0, True)),
+    "logical_or": lambda x, y: sympy.Piecewise((1.0, (x > 0) | (y > 0)), (0.0, True)),
+    "logical_and": lambda x, y: sympy.Piecewise((1.0, (x > 0) & (y > 0)), (0.0, True)),
+    "relu": lambda x: sympy.Piecewise((0.0, x < 0), (x, True)),
 }