diff --git a/lib/decoder.f90 b/lib/decoder.f90
index 2dce5af73..69b7cb983 100644
--- a/lib/decoder.f90
+++ b/lib/decoder.f90
@@ -19,8 +19,8 @@ subroutine decoder(ss,id2,nfsample)
 !$omp threadprivate(/tracer_priv/)
   save
 
-  if(mod(n,2).eq.0) ntrials=10**(nranera/2)
-  if(mod(n,2).eq.1) ntrials=3*10**(nranera/2)
+  if(mod(n,2).eq.0) ntrials=10**(nranera/2.0)
+  if(mod(n,2).eq.1) ntrials=3*10**(nranera/2.0)
   if(nranera.eq.0) ntrials=0
 
   rms=sqrt(dot_product(float(id2(300000:310000)),                            &