X-Original-To: pgsql-sql-postgresql.org@localhost.postgresql.org
Received: from localhost (av.hub.org [200.46.204.144])
	by svr1.postgresql.org (Postfix) with ESMTP id 81EA7DBF3D
	for <pgsql-sql-postgresql.org@localhost.postgresql.org>;
	Tue, 22 Nov 2005 20:13:28 -0400 (AST)
Received: from svr1.postgresql.org ([200.46.204.71])
	by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
	with ESMTP id 16638-10
	for <pgsql-sql-postgresql.org@localhost.postgresql.org>;
	Wed, 23 Nov 2005 00:13:30 +0000 (GMT)
X-Greylist: from auto-whitelisted by SQLgrey-
Received: from megazone.bigpanda.com (megazone.bigpanda.com [64.147.171.210])
	by svr1.postgresql.org (Postfix) with ESMTP id 1576DDBF3B
	for <pgsql-sql@postgresql.org>; Tue, 22 Nov 2005 20:13:25 -0400 (AST)
Received: by megazone.bigpanda.com (Postfix, from userid 1001)
	id 2B2633565C; Tue, 22 Nov 2005 16:13:28 -0800 (PST)
Received: from localhost (localhost [127.0.0.1])
	by megazone.bigpanda.com (Postfix) with ESMTP
	id 2980435648; Tue, 22 Nov 2005 16:13:28 -0800 (PST)
Date: Tue, 22 Nov 2005 16:13:28 -0800 (PST)
From: Stephan Szabo <sszabo@megazone.bigpanda.com>
To: Luca Pireddu <luca@cs.ualberta.ca>
Cc: pgsql-sql@postgresql.org
Subject: Re: argument type problem with plpgsql function
In-Reply-To: <200511221708.10563.luca@cs.ualberta.ca>
Message-ID: <20051122161059.H87037@megazone.bigpanda.com>
References: <200511221708.10563.luca@cs.ualberta.ca>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
X-Virus-Scanned: by amavisd-new at hub.org
X-Spam-Status: No, score=0 required=5 tests=[none]
X-Spam-Score: 0
X-Spam-Level: 
X-Archive-Number: 200511/213
X-Sequence-Number: 23464

On Tue, 22 Nov 2005, Luca Pireddu wrote:

> I wrote a little function that has to work with big numbers
>
> CREATE OR REPLACE FUNCTION blast_evalue(seq_len bigint, db_size bigint,
> bit_score double precision)
>   RETURNS double precision AS $$
> BEGIN
>   RETURN 2^(bit_score) * db_size * seq_len;
> END;
> $$
> LANGUAGE 'plpgsql'
> IMMUTABLE
> RETURNS NULL ON NULL INPUT;
>
> but it doesn't work properly unless I cast the db_size parameter when I call
> the function:
>
> select blast_evalue(273, 8903836, -55.4546);
>  blast_evalue
> --------------
>    2430747228  <- wrong number.  This is 273 * 8903836
> (1 row)
>
> select blast_evalue(273, 8903836::bigint, -55.4546);
>     blast_evalue
> ---------------------
>  4.9231356421437e-08 <- that's correct
> (1 row)
>
> I don't understand why the cast is necessary.  Is there a way to make this
> work without it?

I got the same answer (the second) for both calls from my 8.0 and 8.1
setups, what version were you trying on?