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/* StarPU --- Runtime system for heterogeneous multicore architectures.
*
* Copyright (C) 2010 Université de Bordeaux 1
*
* StarPU is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or (at
* your option) any later version.
*
* StarPU is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*
* See the GNU Lesser General Public License in COPYING.LGPL for more details.
*/
#include <assert.h>
#include <float.h>
#include <limits.h>
#include <starpu.h>
#ifdef STARPU_SLOW_MACHINE
static unsigned nblocks = 512;
static unsigned entries_per_bock = 64;
#else
static unsigned nblocks = 8192;
static unsigned entries_per_bock = 1024;
#endif
#define FPRINTF(ofile, fmt, args ...) do { if (!getenv("STARPU_SSILENT")) {fprintf(ofile, fmt, ##args); }} while(0)
#define TYPE double
#define TYPE_MAX DBL_MAX
#define TYPE_MIN DBL_MIN
static TYPE *x;
static starpu_data_handle_t *x_handles;
/* The first element (resp. second) stores the min element (resp. max). */
static TYPE minmax[2];
static starpu_data_handle_t minmax_handle;
/*
* Codelet to create a neutral element
*/
static void minmax_neutral_cpu_func(void *descr[], void *cl_arg)
{
TYPE *array = (TYPE *)STARPU_VARIABLE_GET_PTR(descr[0]);
/* Initialize current min to the greatest possible value. */
array[0] = TYPE_MAX;
/* Initialize current max to the smallest possible value. */
array[1] = TYPE_MIN;
}
static struct starpu_codelet minmax_init_codelet =
{
.where = STARPU_CPU,
.cpu_funcs = {minmax_neutral_cpu_func, NULL},
.nbuffers = 1
};
/*
* Codelet to perform the reduction of two elements
*/
void minmax_redux_cpu_func(void *descr[], void *cl_arg)
{
TYPE *array_dst = (TYPE *)STARPU_VARIABLE_GET_PTR(descr[0]);
TYPE *array_src = (TYPE *)STARPU_VARIABLE_GET_PTR(descr[1]);
/* Compute the min value */
TYPE min_dst = array_dst[0];
TYPE min_src = array_src[0];
array_dst[0] = STARPU_MIN(min_dst, min_src);
/* Compute the max value */
TYPE max_dst = array_dst[1];
TYPE max_src = array_src[1];
array_dst[1] = STARPU_MAX(max_dst, max_src);
}
static struct starpu_codelet minmax_redux_codelet =
{
.where = STARPU_CPU,
.cpu_funcs = {minmax_redux_cpu_func, NULL},
.nbuffers = 2
};
/*
* Compute max/min within a vector and update the min/max value
*/
void minmax_cpu_func(void *descr[], void *cl_arg)
{
/* The array containing the values */
TYPE *local_array = (TYPE *)STARPU_VECTOR_GET_PTR(descr[0]);
unsigned n = STARPU_VECTOR_GET_NX(descr[0]);
TYPE *minmax = (TYPE *)STARPU_VARIABLE_GET_PTR(descr[1]);
TYPE local_min = minmax[0];
TYPE local_max = minmax[1];
/* Compute the min and the max elements in the array */
unsigned i;
for (i = 0; i < n; i++)
{
TYPE val = local_array[i];
local_min = STARPU_MIN(local_min, val);
local_max = STARPU_MAX(local_max, val);
}
minmax[0] = local_min;
minmax[1] = local_max;
}
static struct starpu_codelet minmax_codelet =
{
.where = STARPU_CPU,
.cpu_funcs = {minmax_cpu_func, NULL},
.nbuffers = 2,
.modes = {STARPU_R, STARPU_REDUX}
};
/*
* Tasks initialization
*/
int main(int argc, char **argv)
{
unsigned long i;
int ret;
ret = starpu_init(NULL);
if (ret == -ENODEV)
return 77;
STARPU_CHECK_RETURN_VALUE(ret, "starpu_init");
unsigned long nelems = nblocks*entries_per_bock;
size_t size = nelems*sizeof(TYPE);
x = (TYPE *) malloc(size);
x_handles = (starpu_data_handle_t *) calloc(nblocks, sizeof(starpu_data_handle_t));
assert(x && x_handles);
/* Initialize the vector with random values */
starpu_srand48(0);
for (i = 0; i < nelems; i++)
x[i] = (TYPE)starpu_drand48();
unsigned block;
for (block = 0; block < nblocks; block++)
{
uintptr_t block_start = (uintptr_t)&x[entries_per_bock*block];
starpu_vector_data_register(&x_handles[block], 0, block_start,
entries_per_bock, sizeof(TYPE));
}
/* Initialize current min */
minmax[0] = TYPE_MAX;
/* Initialize current max */
minmax[1] = TYPE_MIN;
starpu_variable_data_register(&minmax_handle, 0, (uintptr_t)minmax, 2*sizeof(TYPE));
/* Set the methods to define neutral elements and to perform the reduction operation */
starpu_data_set_reduction_methods(minmax_handle, &minmax_redux_codelet, &minmax_init_codelet);
for (block = 0; block < nblocks; block++)
{
struct starpu_task *task = starpu_task_create();
task->cl = &minmax_codelet;
task->handles[0] = x_handles[block];
task->handles[1] = minmax_handle;
int ret = starpu_task_submit(task);
if (ret)
{
STARPU_ASSERT(ret == -ENODEV);
FPRINTF(stderr, "This test can only run on CPUs, but there are no CPU workers (this is not a bug).\n");
return 77;
}
}
for (block = 0; block < nblocks; block++)
{
starpu_data_unregister(x_handles[block]);
}
starpu_data_unregister(minmax_handle);
FPRINTF(stderr, "Min : %e\n", minmax[0]);
FPRINTF(stderr, "Max : %e\n", minmax[1]);
STARPU_ASSERT(minmax[0] <= minmax[1]);
free(x);
free(x_handles);
starpu_shutdown();
return 0;
}
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