api: fix non-integer Mul args

Author: mloubout

devito/finite_differences/differentiable.py

@@ -552,17 +552,13 @@ def __new__(cls, *args, **kwargs):
         nums, others = split(args, lambda e: isinstance(e, (int, float,
                                                             sympy.Number, np.number)))
         scalar = sympy.Mul(*nums)
-        try:
-            scalar = sympy.Integer(scalar)
-        except TypeError:
-            pass
 
         # a*0 -> 0
         if scalar == 0:
             return sympy.S.Zero
 
         # a*1 -> a
-        if scalar == 1:
+        if scalar - 1 == 0:
             args = others
         else:
             args = [scalar] + others

examples/seismic/tutorials/05_staggered_acoustic.ipynb

@@ -130,7 +130,7 @@
        "$\\displaystyle \\left[\\begin{matrix}v_x(t + dt, x + h_x/2, z)\\\\v_z(t + dt, x, z + h_z/2)\\end{matrix}\\right] = \\left[\\begin{matrix}dt \\left(1.0 \\frac{\\partial}{\\partial x} p(t, x, z) + \\frac{v_x(t, x + h_x/2, z)}{dt}\\right)\\\\dt \\left(1.0 \\frac{\\partial}{\\partial z} p(t, x, z) + \\frac{v_z(t, x, z + h_z/2)}{dt}\\right)\\end{matrix}\\right]$"
       ],
       "text/plain": [
-       "Eq(Vector(v_x(t + dt, x + h_x/2, z), v_z(t + dt, x, z + h_z/2)), Vector(dt*(1.0*Derivative(p(t, x, z), x) + v_x(t, x + h_x/2, z)/dt), dt*(1.0*Derivative(p(t, x, z), z) + v_z(t, x, z + h_z/2)/dt)))"
+       "Eq(Vector(v_x(t + dt, x + h_x/2, z), v_z(t + dt, x, z + h_z/2)), Vector(dt*(Derivative(p(t, x, z), x) + v_x(t, x + h_x/2, z)/dt), dt*(Derivative(p(t, x, z), z) + v_z(t, x, z + h_z/2)/dt)))"
       ]
      },
      "execution_count": 7,

tests/test_symbolic_coefficients.py

@@ -202,8 +202,8 @@ def test_staggered_equation(self):
 
         eq_f = Eq(f, f.dx2(weights=weights))
 
-        expected = 'Eq(f(x + h_x/2), 1.0*f(x - h_x/2)/h_x**2 - 2.0*f(x + h_x/2)/h_x**2 '\
-            '+ 1.0*f(x + 3*h_x/2)/h_x**2)'
+        expected = 'Eq(f(x + h_x/2), f(x - h_x/2)/h_x**2 - 2.0*f(x + h_x/2)/h_x**2 '\
+            '+ f(x + 3*h_x/2)/h_x**2)'
         assert(str(eq_f.evaluate) == expected)
 
     @pytest.mark.parametrize('stagger', [True, False])