.TH "MPLRS" "1" "2020.7.28" "July 2020" "mplrs  7\&.2"
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.SH "NAME"
mplrs \- Convert between representations of convex polyhedra (parallel version)\&.
.SH "SYNOPSIS"
.HP \w'\fB\ mpirun\ \fR\fBmplrs\fR\ 'u
\fB mpirun \fR \-np \fInum_proc\ \fR\fBmplrs\fR \fIinfile\fR [\fIoutfile\fR] [\fIoption\fR...]
.br

.SH "DESCRIPTION"
.PP
A polyhedron can be described by a list of inequalities (\fIH\-representation)\fR
or as by a list of its vertices and extreme rays (\fIV\-representation)\fR\&.
\fIlrs\fR
is a C program that converts a H\-representation of a polyhedron to its V\-representation, and vice versa\&.\ \& These problems are known respectively at the
\fIvertex enumeration\fR
and
\fIconvex hull problems\fR\&.
.PP
.SH "USAGE"
.PP
The number of processors
\fInum_proc\fR
specified to
\fBmpirun\fR
should be 4 or higher Unlike lrs
(1),
\fBmplrs\fR
does not support options after the end statement of the input file\&.
.SS "OPTIONS"
.PP
\fBmplrs\fR
supports the following options\&.
.RS 4
\fB\-id <initial depth>\fR [2] the depth of the original tree search to populate the job queue L
.RE
.RS 4
\fB\-maxc <maxcobases>\fR[50 (*scale)] a producer stops and returns all subtrees that are not leaves to L after generating\ \& maxc nodes\ \&\ \&\ \&
.RE
.RS 4
\fB\-maxd <depth>\fR[0] a producer returns all subtrees that are not leaves at depth maxd\&. Zero if not used
.RE
.RS 4
\fB\-lmin <int>\fR[3] if job queue |L|<np*lmin then the maxd parameter is set for all producers 
.RE
.RS 4
\fB\-lmax <int>\fR[lmin] if job queue |L|>np*lmax then then maxc is replaced by maxc*scale
.RE
.RS 4
\fB\-scale <int>\fR[100]used by lmax
.RE
.RS 4
\fB\-hist <file>\fRstore parallelization data in <file> for use by gnuplot, see below
.RE
.RS 4
\fB\-temp <prefix>\fR[/tmp/] store a temporary file for each process\&. Should be specified if /tmp not writeable\&. Using " \-temp\ \& \&./ " will write temporary files to the current directory
.RE
.RS 4
\fB\-freq <file>\fR store frequency data in <file> for use by gnuplot, see below
.RE
.RS 4
\fB\-stop <stopfile> \fR terminate mplrs if a file with name <stopfile> is created in the current directory
.RE
.RS 4
\fB\-checkp <checkpoint file>\fR if mplrs is terminated by \-stop or \-time then it can be restarted using this <checkpoint file> and \-restart
.RE
.RS 4
\fB\-restart <checkpoint file>\fR restart mplrs using previously created <checkpoint file>\&. If used with \-checkp file names should be different!
.RE
.RS 4
\fB\-time <seconds>\fR terminate mplrs after <seconds> of elapsed time
.RE
.RS 4
\fB\-countonly\fR don\*(Aqt output vertices/rays/facets, just count them
.RE
.RS 4
\fB\-maxbuf <n>\fR[500] controls maximum size of worker output buffers
.RE
.RS 4
\fB\-stopafter <n>\fR exit after approximately <n> cobases have been computed (no guarantee about how many vertices/rays/facets computed)
.RE
.RS 4
\fB\-redund\fR perform redundancy check of input file (also see redund )
.RE
The parameters
\fB\-hist\fR
and
\fB\-freq\fR
give interesting information about the degree of parallelization\&.
.SH "EXAMPLE"
.PP
Input file mp5\&.ine is run with 8 processors\&. The output file mp5\&.mplrs is in the distribution\&. This produced 378 subtrees that were enumerated in parallel using 6 producer cores,\ \& 1 core controlling the run and 1 core collecting the output\&.
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.if n \{\
.RS 4
.\}
.nf
      mai20% mpirun \-np 8 mplrs mp5\&.ine mp5\&.mplrs
      *mplrs:lrslib v\&.6\&.0 2015\&.7\&.13(lrsgmp\&.h)8 processes
      *Copyright (C) 1995,2015, David Avis\ \&\ \& avis@cs\&.mcgill\&.ca
      *Input taken from mp5\&.ine
      *Output written to: mp5\&.mplrs
      *Starting depth of 2 maxcobases=50 maxdepth=0 lmin=3 lmax=3 scale=100
      *Phase 1 time: 0 seconds\&.
      *Total number of jobs: 378, L became empty 4 times
      *Totals: vertices=32 rays=0 bases=9041 integer\-vertices=16
      *Elapsed time: 1 seconds\&.
      2\&.285u 0\&.137s 0:01\&.86 129\&.5%\ \&\ \&\ \& 0+0k 0+9976io 36pf+0w
    
.fi
.if n \{\
.RE
.\}
.SH "SEE ALSO"
.BR lrs (1),
.BR lrslib (1)