diff --git a/src/min_hftn.cpp b/src/min_hftn.cpp
index da92ade46db97e4311492d201f93e200f33d7837..7c1c851f45bec322cfbaa306d568db47f02040fd 100644
--- a/src/min_hftn.cpp
+++ b/src/min_hftn.cpp
@@ -277,7 +277,7 @@ int MinHFTN::execute_hftn_(const bool      bPrintProgress,
   //---- LINE SEARCH METHODS DO THIS BY RESTRICTING THE LARGEST CHANGE
   //---- OF ANY ATOM'S COMPONENT TO dmax.  AN EXACT CHECK IS MADE LATER,
   //---- BUT THIS GUIDES DETERMINATION OF A MAX TRUST RADIUS.
-  double  dMaxTrustRadius = dmax * sqrt (_nNumUnknowns);
+  double  dMaxTrustRadius = dmax * sqrt((double) _nNumUnknowns);
   
   dTrustRadius = MIN (dTrustRadius, dMaxTrustRadius);
   double  dLastNewtonStep2 = dMaxTrustRadius;
@@ -1148,7 +1148,7 @@ bool MinHFTN::step_exceeds_TR_(const double    dTrustRadius,
 
 bool MinHFTN::step_exceeds_DMAX_(void) const
 {
-  double  dAlpha = dmax * sqrt (_nNumUnknowns);
+  double  dAlpha = dmax * sqrt((double) _nNumUnknowns);
   
   double  dPInfLocal = 0.0;
   for (int  i = 0; i < nvec; i++)