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/* Copyright (c) 2007-2009, Stanford University
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Stanford University nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY STANFORD UNIVERSITY ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL STANFORD UNIVERSITY BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <stdio.h>
#include <strings.h>
#include <string.h>
#include <stddef.h>
#include <stdlib.h>
#include <unistd.h>
#include <assert.h>
#include <pthread.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <ctype.h>
#include "stddefines.h"
#include "coz.h"
typedef struct {
char x;
char y;
} POINT_T;
typedef struct
{
pthread_t tid;
POINT_T *points;
int num_elems;
long long SX;
long long SY;
long long SXX;
long long SYY;
long long SXY;
} lreg_args;
/* linear_regression_pthread
*
*/
void *linear_regression_pthread(void *args_in)
{
lreg_args* args =(lreg_args*)args_in;
int i;
args->SX = 0;
args->SXX = 0;
args->SY = 0;
args->SYY = 0;
args->SXY = 0;
// ADD UP RESULTS
for (i = 0; i < args->num_elems; i++)
{
//Compute SX, SY, SYY, SXX, SXY
args->SX += args->points[i].x;
args->SXX += args->points[i].x*args->points[i].x;
args->SY += args->points[i].y;
args->SYY += args->points[i].y*args->points[i].y;
args->SXY += args->points[i].x*args->points[i].y;
COZ_PROGRESS;
}
return (void *)0;
}
int main(int argc, char *argv[])
{
int fd;
char * fdata;
char * fname;
struct stat finfo;
int req_units, num_threads, num_procs, i;
pthread_attr_t attr;
lreg_args* tid_args;
// Make sure a filename is specified
if (argv[1] == NULL)
{
printf("USAGE: %s <filename>\n", argv[0]);
exit(1);
}
fname = argv[1];
// Read in the file
CHECK_ERROR((fd = open(fname, O_RDONLY)) < 0);
// Get the file info (for file length)
CHECK_ERROR(fstat(fd, &finfo) < 0);
// Memory map the file
CHECK_ERROR((fdata = (char*)mmap(0, finfo.st_size + 1,
PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0)) == NULL);
CHECK_ERROR((num_procs = sysconf(_SC_NPROCESSORS_ONLN)) <= 0);
printf("The number of processors is %d\n\n", num_procs);
pthread_attr_init(&attr);
pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM);
num_threads = num_procs;
printf("Linear Regression P-Threads: Running...\n");
POINT_T *points = (POINT_T*)fdata;
long long n = (long long) finfo.st_size / sizeof(POINT_T);
req_units = n / num_threads;
tid_args = (lreg_args *)CALLOC(sizeof(lreg_args), num_procs);
// Assign a portion of the points for each thread
for(i = 0; i < num_threads; i++)
{
tid_args[i].points = &points[i*req_units];
tid_args[i].num_elems = req_units;
if(i == (num_threads - 1))
tid_args[i].num_elems = n - i*req_units;
CHECK_ERROR(pthread_create(&tid_args[i].tid, &attr, linear_regression_pthread, (void*)&tid_args[i]) != 0);
}
long long SX_ll = 0, SY_ll = 0, SXX_ll = 0, SYY_ll = 0, SXY_ll = 0;
/* Barrier, wait for all threads to finish */
for (i = 0; i < num_threads; i++)
{
int ret_val;
CHECK_ERROR(pthread_join(tid_args[i].tid, (void **)(void*)&ret_val) != 0);
CHECK_ERROR(ret_val != 0);
SX_ll += tid_args[i].SX;
SY_ll += tid_args[i].SY;
SXX_ll += tid_args[i].SXX;
SYY_ll += tid_args[i].SYY;
SXY_ll += tid_args[i].SXY;
}
free(tid_args);
double a, b, xbar, ybar, r2;
double SX = (double)SX_ll;
double SY = (double)SY_ll;
double SXX= (double)SXX_ll;
double SYY= (double)SYY_ll;
double SXY= (double)SXY_ll;
b = (double)(n*SXY - SX*SY) / (n*SXX - SX*SX);
a = (SY_ll - b*SX_ll) / n;
xbar = (double)SX_ll / n;
ybar = (double)SY_ll / n;
r2 = (double)(n*SXY - SX*SY) * (n*SXY - SX*SY) / ((n*SXX - SX*SX)*(n*SYY - SY*SY));
printf("Linear Regression P-Threads Results:\n");
printf("\ta = %lf\n", a);
printf("\tb = %lf\n", b);
printf("\txbar = %lf\n", xbar);
printf("\tybar = %lf\n", ybar);
printf("\tr2 = %lf\n", r2);
printf("\tSX = %lld\n", SX_ll);
printf("\tSY = %lld\n", SY_ll);
printf("\tSXX = %lld\n", SXX_ll);
printf("\tSYY = %lld\n", SYY_ll);
printf("\tSXY = %lld\n", SXY_ll);
CHECK_ERROR(pthread_attr_destroy(&attr) < 0);
CHECK_ERROR(munmap(fdata, finfo.st_size + 1) < 0);
CHECK_ERROR(close(fd) < 0);
return 0;
}
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