diff --git a/butteraugli/butteraugli.h b/butteraugli/butteraugli.h
index 31824b8..d9b35bd 100755
--- a/butteraugli/butteraugli.h
+++ b/butteraugli/butteraugli.h
@@ -518,7 +518,7 @@ struct RationalPolynomial {
   }
 
   // Evaluates the polynomial at x (in [min_value, max_value]).
-  inline double operator()(const float x) const {
+  inline double operator()(const double x) const {
     // First normalize to [0, 1].
     const double x01 = (x - min_value) / (max_value - min_value);
     // And then to [-1, 1] domain of Chebyshev polynomials.
@@ -527,7 +527,7 @@ struct RationalPolynomial {
     const double yp = EvaluatePolynomial(xc, p);
     const double yq = EvaluatePolynomial(xc, q);
     if (yq == 0.0) return 0.0;
-    return static_cast<float>(yp / yq);
+    return yp / yq;
   }
 
   // Domain of the polynomials; they are undefined elsewhere.
@@ -540,7 +540,7 @@ struct RationalPolynomial {
   double q[5 + 1];
 };
 
-static inline float GammaPolynomial(float value) {
+static inline double GammaPolynomial(double value) {
   // Generated by gamma_polynomial.m from equispaced x/gamma(x) samples.
   static const RationalPolynomial r = {
   0.770000000000000, 274.579999999999984,