Kahan summation for builtin backend inner product
Kahan summation for builtin backend inner product

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