Matrix inversion: Ensure that null check is done against the same type

matrix/SquareMatrix.hpp

@@ -142,12 +142,12 @@ bool inv(const SquareMatrix<Type, M> & A, SquareMatrix<Type, M> & inv)
     for (size_t n = 0; n < M; n++) {
 
         // if diagonal is zero, swap with row below
-        if (fabsf(U(n, n)) < 1e-8f) {
+        if (fabsf(static_cast<float>(U(n, n))) < 1e-8f) {
             //printf("trying pivot for row %d\n",n);
             for (size_t i = n + 1; i < M; i++) {
 
                 //printf("\ttrying row %d\n",i);
-                if (fabsf(U(i, n)) > 1e-8f) {
+                if (fabsf(static_cast<float>(U(i, n))) > 1e-8f) {
                     //printf("swapped %d\n",i);
                     U.swapRows(i, n);
                     P.swapRows(i, n);
@@ -167,7 +167,7 @@ bool inv(const SquareMatrix<Type, M> & A, SquareMatrix<Type, M> & inv)
 #endif
 
         // failsafe, return zero matrix
-        if (fabsf(U(n, n)) < 1e-8f) {
+        if (fabsf(static_cast<float>(U(n, n))) < 1e-8f) {
             return false;
         }