diff --git a/cherab/core/math/integrators/integrators1d.pyx b/cherab/core/math/integrators/integrators1d.pyx
index 54ec4059..7ff9be74 100644
--- a/cherab/core/math/integrators/integrators1d.pyx
+++ b/cherab/core/math/integrators/integrators1d.pyx
@@ -201,6 +201,7 @@ cdef class GaussianQuadrature(Integrator1D):
             double newval, oldval, error, x, c, d
 
         oldval = INFINITY
+        newval = 0
         ibegin = 0
         c = 0.5 * (a + b)
         d = 0.5 * (b - a)