diff --git a/NN/volume.c b/NN/volume.c
index 08c8250ddd751dd436bd02398b30a10378140038..e827973fb755454050c87759056dd530538fac62 100644
--- a/NN/volume.c
+++ b/NN/volume.c
@@ -2082,7 +2082,7 @@ for (i=0;i<mm;i++)
           {
            printf("\n special case 1: constraint 0 not yet reached\n"); 
            opt = 2;
-           junk=cvolumeb(ap,bp,&mm1,&nm1,&opt,&deriv);
+           junk=cvolumeb(ap,bp,&mm1,&nm1,&mm1,&nm1,&opt,&deriv);
            if(junk == -1.)
              {
               *code = -1;