Fix support when building without numpy

Author: mtreinish

symengine/lib/symengine_wrapper.pyx

@@ -295,9 +295,7 @@ def sympy2symengine(a, raise_error=False):
                 return RealDouble(float(str(a)))
         ELSE:
             return RealDouble(float(str(a)))
-    elif isinstance(a, np.float16):
-        return RealDouble(a)
-    elif isinstance(a, np.float32):
+    elif have_numpy and isinstance(a, (np.float16, np.float32)):
         return RealDouble(a)
     elif a is sympy.I:
         return I
@@ -562,9 +560,7 @@ def _sympify(a, raise_error=True):
         return Integer(a)
     elif isinstance(a, float):
         return RealDouble(a)
-    elif isinstance(a, np.float16):
-        return RealDouble(a)
-    elif isinstance(a, np.float32):
+    elif have_numpy and isinstance(a, (np.float16, np.float32)):
         return RealDouble(a)
     elif isinstance(a, complex):
         return ComplexDouble(a)