Newsgroups: comp.parallel.pvm
From: rwhaley@demidoff.cs.utk.edu (R Clint Whaley)
Subject: Re: BLAS for PVM
Keywords: PIM PVM BLAS BLACS
Organization: Computer Science Dept, University of Tennessee, Knoxville
Date: 23 Aug 1994 04:28:26 GMT
Message-ID: <33bttaINN6rl@CS.UTK.EDU>

In article <33a3nb$bj6@rzsun02.rrz.uni-hamburg.de>, am4a012@math.uni-hamburg.de (Thomas Schroeder) writes:
|> 
|> 
|> In article <123@nutmeg.ukc.ac.uk> you wrote:
|> : >>>>> About "BLAS under PVM", Eamonn said:
|> : In article <ecahill-100894195544@ec.hdl.ie> ecahill@hdl.ie (Eamonn Cahill) writes:
|> : Eamonn> Can anyone tell me if there is a public domain parallel BLAS-like
|> : Eamonn> library implmented on PVM?
|> : Eamonn>
|> : Eamonn> Thanks for any help,
|> : amonn>
|> : Eamonn> Eamonn Cahill Hitachi Dublin Laboratory, Trinity College, Dublin
|> : Eamonn> 2,Ireland Ph: +353-1-6798911, Fax: +353-1-6798926, Internet:
|> : Eamonn> ecahill@hdl.ie
|> 
|> : The PIM library described below may be of use.  It runs on networks of
|> : workstations using PVM 3.1, p4 1.2, TCGMSG 4.02, on the Intel Paragon using
|> : the NX library and on the Cray Y-MP2E/233. and was written by Rudnei Dias
|> : da and Tim Hopkins.
|> 
|> : Get it from /pub/misc/netlib/pib/pim.tar.Z on unix.hensa.ac.uk
|> 
|> : Dave
|> : ------
|> : PIM 1.1  
|> : Parallel Iterative Methods package for Systems of Linear Equations  
|> : (Fortran 77 version) 
|> : --------------------------------------------------------------------------------
|> 
|> PIM is not at all like a BLAS-like routine. PIM stands for "Parallel 
|> Iterative Methods" and when you read carefully the introduction you 
|> find the comment from the authors that the user have to provide routines for: 
|> 1. Matrix-vector product  2. Preconditio|> ning step  
|> 3. Inner-products and vector-norms (see page 3 of the doc file). 
|> So you have to build your own BLAS-routines for PVM. But on page 4 of 
|> the doc file of the PIM you can find "... the BLACS project by 
|> Dongarra et al which provides routines to perform distributed operations 
|> over matrices using PVM 3.1." The reference is "J.J. Dongarra, 
|> R.A. van de Geijn, and R.C. Whaley. A users guide to the BLACS v0.1. 
|> Technical report, Computer Science Department, University of Tennessee, 1993."
|> 
|> When someone have made experience with these BLACS it will be fine if 
|> he/she will report this here.
|> 
|> Thomas Schrder (tschroeder@GEOMAT.math.uni-hamburg.de)

There may be some confusion here.  The BLACS (Basic Linear Algebra 
Communication Subprograms) are a message passing interface.  They do not
perform linear algebra computations, but rather provide communication designed
for the linear algebra programmer.  The closest thing to a distributed
BLAS (that I am aware of) which is currently available is a package that 
can be downloaded with ScaLAPACK, called the PBBLAS.  At the next release of 
ScaLAPACK, however, we will release a more easy-to-use package known as the 
PBLAS.  I would recommend waiting for this guy.  If you wish to see what
ScaLAPACK has to offer, you can mail to netlib@ornl.gov, and in the body
of the message type "send index from scalapack".

All of ScaLAPACK uses the BLACS for its communication.  The BLACS are
supported on PVM, as well as several other platforms, and thus ScaLAPACK
(and the PBBLAS) run with PVM.

Further information on the BLACS can be obtained via mosaic with
URL = ftp://cs.utk.edu/pub/rwhaley/HTML/Blacs.html.

-- Clint Whaley

