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SuiteSparse_config.c
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Sun, Oct 20, 15:35

SuiteSparse_config.c
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/* ========================================================================== */
/* === SuiteSparse_config =================================================== */
/* ========================================================================== */
/* Copyright (c) 2012, Timothy A. Davis. No licensing restrictions
* apply to this file or to the SuiteSparse_config directory.
* Author: Timothy A. Davis.
*/
#include "SuiteSparse_config.h"
/* -------------------------------------------------------------------------- */
/* SuiteSparse_malloc: malloc wrapper */
/* -------------------------------------------------------------------------- */
void *SuiteSparse_malloc /* pointer to allocated block of memory */
(
size_t nitems, /* number of items to malloc (>=1 is enforced) */
size_t size_of_item, /* sizeof each item */
int *ok, /* TRUE if successful, FALSE otherwise */
SuiteSparse_config *config /* SuiteSparse-wide configuration */
)
{
void *p ;
if (nitems < 1) nitems = 1 ;
if (nitems * size_of_item != ((double) nitems) * size_of_item)
{
/* Int overflow */
*ok = 0 ;
return (NULL) ;
}
if (!config || config->malloc_memory == NULL)
{
/* use malloc by default */
p = (void *) malloc (nitems * size_of_item) ;
}
else
{
/* use the pointer to malloc in the config */
p = (void *) (config->malloc_memory) (nitems * size_of_item) ;
}
*ok = (p != NULL) ;
return (p) ;
}
/* -------------------------------------------------------------------------- */
/* SuiteSparse_free: free wrapper */
/* -------------------------------------------------------------------------- */
void *SuiteSparse_free /* always returns NULL */
(
void *p, /* block to free */
SuiteSparse_config *config /* SuiteSparse-wide configuration */
)
{
if (p)
{
if (!config || config->free_memory == NULL)
{
/* use free by default */
free (p) ;
}
else
{
/* use the pointer to free in the config */
(config->free_memory) (p) ;
}
}
return (NULL) ;
}
/* -------------------------------------------------------------------------- */
/* SuiteSparse_tic: return current wall clock time */
/* -------------------------------------------------------------------------- */
/* Returns the number of seconds (tic [0]) and nanoseconds (tic [1]) since some
* unspecified but fixed time in the past. If no timer is installed, zero is
* returned. A scalar double precision value for 'tic' could be used, but this
* might cause loss of precision because clock_getttime returns the time from
* some distant time in the past. Thus, an array of size 2 is used.
*
* The timer is enabled by default. To disable the timer, compile with
* -DNTIMER. If enabled on a POSIX C 1993 system, the timer requires linking
* with the -lrt library.
*
* example:
*
* double tic [2], r, s, t ;
* SuiteSparse_tic (tic) ; // start the timer
* // do some work A
* t = SuiteSparse_toc (tic) ; // t is time for work A, in seconds
* // do some work B
* s = SuiteSparse_toc (tic) ; // s is time for work A and B, in seconds
* SuiteSparse_tic (tic) ; // restart the timer
* // do some work C
* r = SuiteSparse_toc (tic) ; // s is time for work C, in seconds
*
* A double array of size 2 is used so that this routine can be more easily
* ported to non-POSIX systems. The caller does not rely on the POSIX
* <time.h> include file.
*/
#ifdef SUITESPARSE_TIMER_ENABLED
#include <time.h>
void SuiteSparse_tic
(
double tic [2] /* output, contents undefined on input */
)
{
/* POSIX C 1993 timer, requires -librt */
struct timespec t ;
clock_gettime (CLOCK_MONOTONIC, &t) ;
tic [0] = (double) (t.tv_sec) ;
tic [1] = (double) (t.tv_nsec) ;
}
#else
void SuiteSparse_tic
(
double tic [2] /* output, contents undefined on input */
)
{
/* no timer installed */
tic [0] = 0 ;
tic [1] = 0 ;
}
#endif
/* -------------------------------------------------------------------------- */
/* SuiteSparse_toc: return time since last tic */
/* -------------------------------------------------------------------------- */
/* Assuming SuiteSparse_tic is accurate to the nanosecond, this function is
* accurate down to the nanosecond for 2^53 nanoseconds since the last call to
* SuiteSparse_tic, which is sufficient for SuiteSparse (about 104 days). If
* additional accuracy is required, the caller can use two calls to
* SuiteSparse_tic and do the calculations differently.
*/
double SuiteSparse_toc /* returns time in seconds since last tic */
(
double tic [2] /* input, not modified from last call to SuiteSparse_tic */
)
{
double toc [2] ;
SuiteSparse_tic (toc) ;
return ((toc [0] - tic [0]) + 1e-9 * (toc [1] - tic [1])) ;
}
/* -------------------------------------------------------------------------- */
/* SuiteSparse_time: return current wallclock time in seconds */
/* -------------------------------------------------------------------------- */
/* This function might not be accurate down to the nanosecond. */
double SuiteSparse_time /* returns current wall clock time in seconds */
(
void
)
{
double toc [2] ;
SuiteSparse_tic (toc) ;
return (toc [0] + 1e-9 * toc [1]) ;
}

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