Path: news.mathworks.com!not-for-mail
From: "Michael Hui" <myhui@yahoo.com>
Newsgroups: comp.soft-sys.matlab
Subject: Fixed-Point Toolbox and BLAS
Date: Fri, 18 Jul 2008 21:00:22 +0000 (UTC)
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I have a question regarding coding tricks one can use to
make Fixed-Point Toolbox run as fast as possible.

I have read elsewhere on this newsgroup that BLAS

http://www.intel.com/cd/software/products/asmo-na/eng/266858.htm

is not used for calculations in equations defined using
Fixed-Point Toolbox.

But what if I code my sum-of-products where every term on
the RHS have their SumMode and ProductMode set to the
FullPrecision default, and the tool already knows at
compile time that the equation's LHS will have a mantissa
with fewer bits than the floating point mantissa limit?
That means the sum-of-products can be executed using BLAS,
and any rounding or saturation can be handled afterwards.

Or is it true that Fixed-Point Toolbox calculations never
use BLAS, so no matter how I code it, there is no way to
approach the speed of floating point sum-of-products
calculations in regular M code?