refine

src/main/java/org/apache/commons/math4/analysis/function/Logit.java

@@ -171,15 +171,16 @@ public DerivativeStructure value(final DerivativeStructure t)
 
         // function value
         final double f0 = f[0] = FastMath.log((x - lo) / (hi - x));
+        final int fLen = f.length;
         if (Double.isInfinite(f0)) {
-            if (f.length > 1) {
+            if (fLen > 1) {
                 final double f1 = f[1] = Double.POSITIVE_INFINITY;
                 // fill the array with infinities
                 // (for x close to lo the signs will flip between -inf and +inf,
                 //  for x close to hi the signs will always be +inf)
                 // this is probably overkill, since the call to compose at the end
                 // of the method will transform most infinities into NaN ...
-                for (int i = 2; i < f.length; ++i) {
+                for (int i = 2; i < fLen; ++i) {
                     f[i] = (i & 1) == 0 ? f0 : f1;
                 }
             }