Get rid of sign mismatch warnings
Get rid of sign mismatch warnings

ddemidov/amgcl,ddemidov/amgcl,ddemidov/amgcl,huahbo/amgcl,dondieselkopf/amgcl,huahbo/amgcl,dondieselkopf/amgcl,dondieselkopf/amgcl,huahbo/amgcl,ddemidov/amgcl