Retrieves the current table used in the GFSR generator.
Synopsis
#include <imsls.h>
void imsls_random_GFSR_table_get (int **table, ..., 0)
Required Arguments
int **table
(Output)
Address of a pointer to an array of length 1565 containing the table
used in the GFSR generators. Typically, int *table is
declared and &table is used as
an argument.
Synopsis with Optional Arguments
#include <imsls.h>
void
imsls_random_GFSR_table_get (int
**table,
IMSLS_RETURN_USER,
int
r[],
0)
Optional Arguments
IMSLS_RETURN_USER, int r[]
(Output)
User-supplied array of length 1565 containing the table used in the GFSR generators.
Description
The values in table are initialized by the IMSL random number generators. The values are all positive except if the user wishes to reinitialize the array, in which case the first element of the array is input as a nonpositive value. (Usually, one should avoid reinitializing these arrays, but it might be necessary sometimes in restarting a simulation.) If the first element of table is set to a nonpositive value on the call to imsls_random_GFSR_table_set, on the next invocation of a routine to generate random numbers using a GFSR method, the appropriate array will be reinitialized.
Example
In this example, three separate simulation streams are used, each with a different form of the generator. Each stream is stopped and restarted. (Although this example is obviously an artificial one, there may be reasons for maintaining separate streams and stopping and restarting them because of the nature of the usage of the random numbers coming from the separate streams.)
#include <stdio.h>
#include <imsls.h>
int main()
{
float *r, *table;
int nr, iseed1, iseed2, iseed7;
int *itable;
nr = 5;
iseed1 = 123457;
iseed2 = 123457;
iseed7 = 123457;
/* Begin first stream, iopt = 1 (by default) */
imsls_random_seed_set (iseed1);
r = imsls_f_random_uniform (nr, 0);
iseed1 = imsls_random_seed_get ();
imsls_f_write_matrix ("First stream output", 1, 5, r,
IMSLS_NO_COL_LABELS,
IMSLS_NO_ROW_LABELS, 0);
printf(" Output seed\t%d\n\n", iseed1);
free(r);
/* Begin second stream, iopt = 2 */
imsls_random_option (2);
imsls_random_seed_set (iseed2);
r = imsls_f_random_uniform (nr, 0);
iseed2 = imsls_random_seed_get ();
imsls_f_random_table_get (&table, 0);
imsls_f_write_matrix ("Second stream output", 1, 5, r,
IMSLS_NO_COL_LABELS,
IMSLS_NO_ROW_LABELS, 0);
printf(" Output seed\t%d\n\n", iseed2);
free(r);
/* Begin third stream, iopt = 7 */
imsls_random_option (7);
imsls_random_seed_set (iseed7);
r = imsls_f_random_uniform (nr, 0);
iseed7 = imsls_random_seed_get ();
imsls_random_GFSR_table_get (&itable, 0);
imsls_f_write_matrix ("Third stream output", 1, 5, r,
IMSLS_NO_COL_LABELS,
IMSLS_NO_ROW_LABELS, 0);
printf(" Output seed\t%d\n\n", iseed7);
free(r);
/* Reinitialize seed and resume first stream */
imsls_random_option (1);
imsls_random_seed_set (iseed1);
r = imsls_f_random_uniform (nr, 0);
iseed1 = imsls_random_seed_get ();
imsls_f_write_matrix ("First stream output", 1, 5, r,
IMSLS_NO_COL_LABELS,
IMSLS_NO_ROW_LABELS, 0);
printf(" Output seed\t%d\n\n", iseed1);
free(r);
/*
* Reinitialize seed and table for shuffling and
* resume second stream
*/
imsls_random_option (2);
imsls_random_seed_set (iseed2);
imsls_f_random_table_set (table);
r = imsls_f_random_uniform (nr, 0);
iseed2 = imsls_random_seed_get ();
imsls_f_write_matrix ("Second stream output", 1, 5, r,
IMSLS_NO_COL_LABELS,
IMSLS_NO_ROW_LABELS, 0);
printf(" Output seed\t%d\n\n", iseed2);
free(r);
/*
* Reinitialize seed and table for GFSR and
* resume third stream.
*/
imsls_random_option (7);
imsls_random_seed_set (iseed7);
imsls_random_GFSR_table_set (itable);
r = imsls_f_random_uniform (nr, 0);
iseed7 = imsls_random_seed_get ();
imsls_f_write_matrix ("Third stream output", 1, 5, r,
IMSLS_NO_COL_LABELS,
IMSLS_NO_ROW_LABELS, 0);
printf(" Output seed\t%d\n\n", iseed7);
free(r);
}
Output
First stream output
0.9662 0.2607 0.7663 0.5693 0.8448
Output seed 1814256879
Second stream output
0.7095 0.1861 0.4794 0.6038 0.3790
Output seed 1965912801
Third stream output
0.3914 0.0263 0.7622 0.0281 0.8997
Output seed 1932158269
First stream output
0.0443 0.9872 0.6014 0.8964 0.3809
Output seed 817878095
Second stream output
0.2557 0.4788 0.2258 0.3455 0.5811
Output seed 2108806573
Third stream output
0.7519 0.5084 0.9070 0.0910 0.6917
Output seed 1485334679
