// simeq.hpp  solve A[n,n]*X[n]=Y[n] for vector X 
// A preserved 
#include <complex>
using namespace std;
typedef complex<double> cmplx;
void simeq(int n, cmplx A[], cmplx Y[], cmplx X[]);
void simeq2(int n, cmplx **A, cmplx Y[],
	           cmplx X[]); // A[n][n]
// last column of B is Y, all overwritten 
void simeqb(int n, cmplx B[], cmplx X[]);
void simeq2b(int n, cmplx **B, cmplx X[]); // B[n][n+1]