diff --git a/src/libnptm/lapack_calls.cpp b/src/libnptm/lapack_calls.cpp
index ece8df6097a3af1895afa97c3a9300435a48d341..a23036ce0a800e8406e5484efb505e8714ab3336 100644
--- a/src/libnptm/lapack_calls.cpp
+++ b/src/libnptm/lapack_calls.cpp
@@ -156,7 +156,7 @@ void zinvert_and_refine(dcomplex **mat, np_int n, int &jer, int &maxiters, doubl
     zaxpy_(&n, &dcone, id, &incx, arr_residual, &incy);
     double oldmax = 0;
     if (refinemode >0) {
-      np_int maxindex = izamax_(&n, arr_residual, &incx);
+      np_int maxindex = izamax_(&nn, arr_residual, &incx);
 #ifdef USE_MKL
       oldmax = cabs(arr_residual[maxindex].real + I*arr_residual[maxindex].imag);
 #else
@@ -173,7 +173,7 @@ void zinvert_and_refine(dcomplex **mat, np_int n, int &jer, int &maxiters, doubl
       zgemm_(&transa, &transa, &n, &n, &n, &dcmone, arr, &n, arr_orig, &n, &dczero, arr_residual, &n);
       zaxpy_(&n, &dcone, id, &incx, arr_residual, &incy);
       if ((refinemode==2) || ((refinemode==1) && (iter == (maxiters-1)))) {
-	np_int maxindex = izamax_(&n, arr_residual, &incx);
+	np_int maxindex = izamax_(&nn, arr_residual, &incx);
 #ifdef USE_MKL
 	double newmax = cabs(arr_residual[maxindex].real + I*arr_residual[maxindex].imag);
 #else