From 7626162d6cf3acac386ed8198003d7dbb5ef10b4 Mon Sep 17 00:00:00 2001 From: Marco van Oort <marcovoort@gmail.com> Date: Thu, 3 Nov 2016 16:47:28 +0100 Subject: [PATCH] Update documentation on mondriaanOpt about the imbalance subtlety and the matlab interface --- docs/MATLAB.html | 17 +++++++++++++++-- docs/USERS_GUIDE_OPT.html | 17 +++++++++++++++-- 2 files changed, 30 insertions(+), 4 deletions(-) diff --git a/docs/MATLAB.html b/docs/MATLAB.html index 2cf1aec..a02a9d6 100644 --- a/docs/MATLAB.html +++ b/docs/MATLAB.html @@ -244,6 +244,18 @@ This concludes this small tutorial. More information is available through issueing <tt>help mondriaan</tt> from within MATLAB. </p> +<h3>MondriaanOpt</h3> +Apart from Mondriaan itself, also MondriaanOpt is available in MATLAB through the MatlabMondriaanOpt MEX routine. +Example matlab functions are given in mondriaanOpt.m and mondriaanOptPlot.m. +The interface of mondriaanOpt is as follows: +<ul> +<li><tt>[I, s] = mondriaanOpt(A, Imbalance, Volume)</tt></li> +</ul> +Here, <tt>A</tt> is the sparse matrix to be partitioned, <tt>Imbalance</tt> is the maximum allowed load imbalance, +<tt>Volume</tt> is the initial upper bound on the volume, <tt>I</tt> contains the partitioning information and +<tt>s</tt> contains statistics about the run. +For more information, type <tt>help mondriaanOpt</tt> or <tt>help mondriaanOptPlot</tt> in MATLAB. + <h3>References</h3> <p> @@ -263,11 +275,12 @@ Vol. 32, Issue 6, pp. 3426-3446 (2010).<br> </p> <hr> <p> -Last updated: 21st of August, 2013.<br><br> +Last updated: November 3, 2016.<br><br> July 27, 2010 by Bas Fagginger Auer,<br> December 10, 2010 by A. N. Yzelman,<br> March 27, 2012 by Bas Fagginger Auer,<br> -August 29, 2013 by Rob Bisseling and Bas Fagginger Auer.<br><br> +August 29, 2013 by Rob Bisseling and Bas Fagginger Auer.<br> +November 3, 2016 by Marco van Oort.<br><br> To <a href="http://www.staff.science.uu.nl/~bisse101/Mondriaan"> Home page Mondriaan package</a>.</p> diff --git a/docs/USERS_GUIDE_OPT.html b/docs/USERS_GUIDE_OPT.html index e6a6705..8db3985 100644 --- a/docs/USERS_GUIDE_OPT.html +++ b/docs/USERS_GUIDE_OPT.html @@ -54,6 +54,8 @@ The MondriaanOpt program has the following interface: <ul><li><tt>% ./tools/MondriaanOpt matrix [P [eps]] [options]</tt></li></ul> One, two or three parameters may be passed, after which further options may be given. Either [eps], -e or -k must be passed, and it is advised to pass -v (see <a href="#opts">options</a>). +Take note that while MondriaanOpt may be called with the same parameters as Mondriaan, the actual problem +being solved may be <a href="#constraint">slightly different</a>. </p> <p> @@ -238,6 +240,17 @@ Apart from the matrix, at least one of [eps], -e or -k must be given, defining t </tbody> </table> +<h3><a name="constraint">Difference in imbalance constraints</a></h3> +While the command line interface of MondriaanOpt can be used just as Mondriaan, there is a subtle difference in the problem being solved in these two. +More precisely, with <tt>N</tt> being the total number of nonzeros, <tt>p</tt> being the total number of processors (which equals 2) and +<tt>load</tt> the number of nonzeros assigned to a processor, compare: +<ul> + <li>the imbalance constraint <tt>load <= (1+epsilon) (N/p)</tt> which is used in Mondriaan (In the code, this amounts to <tt>floor( ((1+epsilon)*N)/p )</tt>.), and</li> + <li>the imbalance constraint <tt>load <= (1+epsilon) ceil(N/p)</tt> which is used in MondriaanOpt.</li> +</ul> +As <tt>p=2</tt>, this difference may only be of importance whenever <tt>N</tt> is odd. +In [<a href="#cite1">1,p.2</a>] it is explained that this different choice was made to ensure feasibility of the problem, even if <tt>epsilon=0</tt>. + <h3><a name="matl">Using MondriaanOpt in MATLAB</a></h3> @@ -257,8 +270,8 @@ Daniel M. Pelt and Rob H. Bisseling, <i>Journal of Parallel and Distributed Comp <hr> <p> -Last updated: October 27, 2016.<br><br> -October 27, 2016 by Marco van Oort.<br><br> +Last updated: November 3, 2016.<br><br> +November 3, 2016 by Marco van Oort.<br><br> To <a href="http://www.staff.science.uu.nl/~bisse101/Mondriaan"> the Mondriaan package home page</a>.</p> -- GitLab