Centre Blaise Pascal » Bench4GPU

#!/usr/bin/env python3

import numpy as np

import pyopencl as cl

a_np = np.random.rand(50000).astype(np.float32)

b_np = np.random.rand(50000).astype(np.float32)

ctx = cl.create_some_context()

queue = cl.CommandQueue(ctx)

mf = cl.mem_flags

a_g = cl.Buffer(ctx, mf.READ_ONLY | mf.COPY_HOST_PTR, hostbuf=a_np)

b_g = cl.Buffer(ctx, mf.READ_ONLY | mf.COPY_HOST_PTR, hostbuf=b_np)

prg = cl.Program(ctx, """

__kernel void sum(

    __global const float *a_g, __global const float *b_g, __global float *res_g)

{

  int gid = get_global_id(0);

  res_g[gid] = a_g[gid] + b_g[gid];

}

""").build()

res_g = cl.Buffer(ctx, mf.WRITE_ONLY, a_np.nbytes)

knl = prg.sum  # Use this Kernel object for repeated calls

knl(queue, a_np.shape, None, a_g, b_g, res_g)

res_np = np.empty_like(a_np)

cl.enqueue_copy(queue, res_np, res_g)

# Check on CPU with Numpy:

print(res_np - (a_np + b_np))

print(np.linalg.norm(res_np - (a_np + b_np)))

assert np.allclose(res_np, a_np + b_np)