fix for MacOS (pow overload)

FastMinKernel.cpp

@@ -401,7 +401,7 @@ void FastMinKernel::hikUpdateLookupTable(double * T, const double & alphaNew, co
     {
         double fval;
         int q_bin = q.quantize(x_i);
-        if (q_bin > j)
+        if (q_bin > (int)j)
           fval = prototypes[j];
         else
           fval = x_i;      
@@ -814,7 +814,7 @@ double FastMinKernel::getFrobNormApprox()
       }
       secondTerm /= 3.0;
       secondTerm = pow(secondTerm, 2);
-      secondTerm *= (pow(this->n,2) - this->n);
+      secondTerm *= (this->n * ( this->n - 1 ));
       frobNormApprox += secondTerm;