using static System.Console;

class main{
static void Main(string[] args){
int n=7,m=n;
if(args.Length>0){
	n=int.Parse(args[0]);
	m=n;
	}
var A=new matrix(n,m);
var rnd=new System.Random();
for(int i=0;i<A.size1;i++)
	for(int j=0;j<A.size2;j++)
		A[i,j]=2*(rnd.NextDouble()-0.5);
if(n<9){
	A.print("random matrix A:");
	var b=new vector(m);
	for(int i=0;i<b.size;i++)
		b[i]=rnd.NextDouble();
	b.print("random vector b:\n");
	var qra=new qrdecomposition(A);
	var x=qra.solve(b);
	x.print("solution x to system A*x=b:\n");
	var Ax=A*x;
	Ax.print("check: A*x (should be equal b):\n");
	if(vector.approx(Ax,b)) WriteLine("test passed");
	else WriteLine("test failed");
	var B=qra.inverse();
	var BA=B*A; BA.print("A^-1*A=");
	var AB=A*B; AB.print("A*A^-1=");
	}
else{
	Write($"n={n}\n");
	var qra=new qrdecomposition(A);
	}
}
}