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#ifndef __ROTATE_H__
#define __ROTATE_H__
#include "linalg.h"
#include "matrix.h"
__device__ const Matrix IDENTITY_MATRIX = {1,0,0,0,1,0,0,0,1};
__device__ __host__ Matrix make_rotation_matrix(float phi, const float3 &n)
{
/* rotate points counterclockwise, when looking towards +infinity,
through an angle `phi` about the axis `n`. */
float cos_phi = cosf(phi);
float sin_phi = sinf(phi);
return IDENTITY_MATRIX*cos_phi + (1-cos_phi)*outer(n,n) +
sin_phi*make_matrix(0,n.z,-n.y,-n.z,0,n.x,n.y,-n.x,0);
}
__device__ __host__ float3 rotate(const float3 &a, float phi, const float3 &n)
{
return make_rotation_matrix(phi,n)*a;
}
#endif
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