database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-06-27 23:21:58 +03:00
Code Activity

Attached is a patch implementing factorial(), returning numeric. Points

Browse Source 
to note:

1) arttype is numeric. I thought this was the best way of allowing
arbitarily large factorials, even though factorial(2^63) is a large
number. Happy to change to integers if this is overkill.
2) since we're accepting numeric arguments, the patch tests for floats.
If a numeric is passed with non-zero decimal portion, an error is raised
since (from memory) they are undefined.

Gavin Sherry
This commit is contained in:
Bruce Momjian
2003-12-01 21:52:38 +00:00
parent af03663878
commit 04a4821ade
9 changed files with 74 additions and 100 deletions
Download Patch File Download Diff File Expand all files Collapse all files

51
src/backend/utils/adt/numeric.c
View File

@ -14,7 +14,7 @@
* Copyright (c) 1998-2003, PostgreSQL Global Development Group
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/adt/numeric.c,v 1.68 2003/11/29 19:51:59 pgsql Exp $
* $PostgreSQL: pgsql/src/backend/utils/adt/numeric.c,v 1.69 2003/12/01 21:52:37 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -1288,6 +1288,55 @@ numeric_larger(PG_FUNCTION_ARGS)
* ----------------------------------------------------------------------
*/
/*
* numeric_fac()
* Computer factorial
*/
Datum
numeric_fac(PG_FUNCTION_ARGS)
{
int64 num = PG_GETARG_INT64(0);
NumericVar count;
NumericVar fact;
NumericVar zerovar;
NumericVar result;
Numeric res;
if(num < 1) {
res = make_result(&const_one);
PG_RETURN_NUMERIC(res);
}
init_var(&fact);
init_var(&count);
init_var(&result);
init_var(&zerovar);
zero_var(&zerovar);
int8_to_numericvar((int64)num, &result);
set_var_from_var(&const_one, &count);
for(num = num - 1; num > 0; num--) {
set_var_from_var(&result,&count);
int8_to_numericvar((int64)num,&fact);
mul_var(&count, &fact, &result, count.dscale + fact.dscale);
}
res = make_result(&count);
free_var(&count);
free_var(&fact);
free_var(&result);
free_var(&zerovar);
PG_RETURN_NUMERIC(res);
}
/*
* numeric_sqrt() -