submat.h

#ifndef SUBMAT_H
#define SUBMAT_H
#include "mat.h"
/* This class only is available on the GPU
   Gets the BLOCK_SIZE x BLOCK_SIZE submatrix of a matrix that is
   located col sub-matrices to the right and row sub-matrices down
   from the upper-left corner of A */

class subMatrix {
public:
    /* Member Data */
    int width;
    int height;
    int stride;
    float* elements;

    __device__
        subMatrix(Matrix A, int sub_size, int row, int col)
    {
        width = sub_size;
        height = sub_size;
        stride = A.stride;
        // memory at spot
        elements = &A.elements[stride * width * row + height * col];
    }
    //Get matrix element
    __device__ inline float GetElem(const int row, const int col)
    {
        return elements[row * stride + col];
    }

    //Set a matrix element
    __device__ inline void SetElem(const int row, const int col, const float value)
    {
        elements[row * stride + col] = value;
    }
};
#endif