def openCL_multiplication(matrix1, matrix2, res):

import pyopencl as cl
import numpy as np
import numpy.linalg as la

ctx = cl.create_some_context()
queue = cl.CommandQueue(ctx)

mf = cl.mem_flags
a_buf = cl.Buffer(ctx, mf.READ_ONLY | mf.COPY_HOST_PTR, hostbuf=matrix1)
b_buf = cl.Buffer(ctx, mf.READ_ONLY | mf.COPY_HOST_PTR, hostbuf=matrix2)
dest_buf = cl.Buffer(ctx, mf.WRITE_ONLY, matrix1.nbytes )


prg = cl.Program(ctx, """
    __kernel void multiplymatrices(const unsigned int size, __global float * matrix1, __global float * matrix2, __global float * res) {

    int i = get_global_id(1); 
    int j = get_global_id(0);

    res[i + size * j] = 0;

    for (int k = 0; k < size; k++)
    {
        res[i + size * j] += matrix1[i + size * k] * matrix2[k + size * j];
    }

    }
    """).build()

t0 = datetime.datetime.now()

prg.multiplymatrices(queue, matrix1.shape, None,np.int32(len(matrix1)) ,a_buf, b_buf, dest_buf)

final_matrix = np.empty_like(matrix1)
cl.enqueue_copy(queue, final_matrix , dest_buf)

print  final_matrix


delta_t = datetime.datetime.now() - t0
print 'OpenCL Multiplication: ' + str(delta_t)

return final_matrix