MTL 向量旋转 拉伸 函数

//整理　by RobinKin

#include "mtl/mtl.h"
#include "mtl/utils.h"
#include "mtl/linalg_vec.h"

/*
Eliminates the last element of vector y.

Sample Output

[1,2,3,4,5,]
[2,4,8,16,32,]
[2.1304,4.2608,8.36723,16.4257,32.3883,]
[-0.679258,-1.35852,-1.72902,-1.48202,0,]

*/

using namespace mtl;

typedef external_vec<double> Vec;

int
main()
{
//begin
const int N = 5;
double dx[] = { 1, 2, 3, 4, 5 };
double dy[] = { 2, 4, 8, 16, 32};

Vec x(dx, N), y(dy, N);
//end
print_vector(x);
print_vector(y);
//begin

double a = x[N-1];
double b = y[N-1];

givens_rotation<double> rot(a, b);

//对于上述的５对(x,y)分别 加上　旋转，　旋转的读数是　arctg(a/b) 拉伸　sqrt( a*a,b*b)

rot.apply(x, y);
//end

print_vector(x);
print_vector(y);

return 0;
}