rand_mt.cc File Reference

Generate uniformly distributed random number from interval [0,1[. More...

#include "sqlstat.h"
#include "sqlrand.h"

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Functions
my_bool	rand_mt_init (UDF_INIT *initid, UDF_ARGS *args, char *message)
	Called before first usage of function. More...
double	rand_mt (UDF_INIT *initid, UDF_ARGS *args, char *is_null, char *error)
	Retrieve Mersenne Twister random number. More...
void	rand_mt_deinit (UDF_INIT *initid)
	Called after last access to function. More...

Detailed Description

Generate uniformly distributed random number from interval [0,1[.

CREATE FUNCTION rand_mt RETURNS REAL SONAME 'libsqlstat.so';
SELECT rand_mt() FROM mytab;
DROP FUNCTION rand_mt;

Definition in file rand_mt.cc.

Function Documentation

double rand_mt	(	UDF_INIT *	initid,
		UDF_ARGS *	args,
		char *	is_null,
		char *	error
	)

Retrieve Mersenne Twister random number.

A double random number in the range [0,1[ is generated. It has 53 random bits.

Parameters

initid	function description
args	argument values
is_null	result is NULL
error	error message

Returns

random number

Definition at line 81 of file rand_mt.cc.

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rand_mt_deinit

(

UDF_INIT *

initid

)

Called after last access to function.

Deallocate memory for counter and sums.

Parameters

initid

Definition at line 92 of file rand_mt.cc.

my_bool rand_mt_init	(	UDF_INIT *	initid,
		UDF_ARGS *	args,
		char *	message
	)

Called before first usage of function.

Checksparameters.
Indicate type of return value.

Parameters

initid	function description
args	parameters
message	error message

Returns

success = 0

Definition at line 48 of file rand_mt.cc.

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