chacowrap.cc

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/* $Header: /var/cvs/mbdyn/mbdyn/mbdyn-1.0/libraries/libmbwrap/chacowrap.cc,v 1.8 2011/05/19 11:24:38 masarati Exp $ */
/* A simple interface to the Chaco graph partioning library.  It does
 * some small conversions so that it is easy to substitute for Metis.
 *
 * MBDyn (C) is a multibody analysis code. 
 * http://www.mbdyn.org
 *
 * Copyright (C) 2003 Mississippi State University
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation (version 2 of the License).
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "mbconfig.h"           /* This goes first in every *.c,*.cc file */

#include <vector>
#include <iostream>

#include "chacowrap.h"

extern "C" {
/*
 * NOTE: the name "interface" has been reported (by Patrick Rix) 
 * to cause issues with gcc 4.10
 */
int       interface(
                int       nvtxs,                /* number of vertices in full graph */
                int      *start,                /* start of edge list for each vertex */
                int      *adjacency,            /* edge list data */
                int      *vwgts,                /* weights for all vertices */
                float    *ewgts,                /* weights for all edges */
                float    *x, float *y, float *z,/* coordinates for inertial method */
                char     *outassignname,        /* name of assignment output file */
                char     *outfilename,          /* output file name */
                short    *assignment,           /* set number of each vtx (length n) */
                int       architecture,         /* 0 => hypercube, d => d-dimensional mesh */
                int       ndims_tot,            /* total number of cube dimensions to divide */
                int       mesh_dims[3],         /* dimensions of mesh of processors */
                double   *goal,                 /* desired set sizes for each set */
                int       global_method,        /* global partitioning algorithm */
                int       local_method,         /* local partitioning algorithm */
                int       rqi_flag,             /* should I use RQI/Symmlq eigensolver? */
                int       vmax,                 /* how many vertices to coarsen down to? */
                int       ndims,                /* number of eigenvectors (2^d sets) */
                double    eigtol,               /* tolerance on eigenvectors */
                long      seed                  /* for random graph mutations */
        );
}

extern "C" int FREE_GRAPH;

void
chaco_interface(
                const int       iTotVertices,
                int             *start,
                int             *adjacency,
                int             *vertex_weights,
                int             *comm_weights,          /* unsupported */
                int             *edge_weights,
                const int       num_processors,
                int             *pParAmgProcs
        )
{
        std::vector<short> set_assignment(iTotVertices);

        const int architecture(1),      /* The computers are connected as a
                                         * simple one-dimensional mesh
                                         * 0 => hypercube, d => d-dimensional mesh */
                global_method(2),       /* Use Spectral decomposition */
                local_method(1),        /* With KL local refinement */
                rqi_flag(0),            /* Use Lanczos for solving the
                                         * eigenvalue problem for spectral
                                         * decomposition */
                vmax(100),              /* When to stop coarsening.  Not used */
                seed(7654321);          /* A random number seed */
        int     mesh_dims[] = {         /* if architecture > 0, mesh size goes here */
                num_processors, 1, 1
        };
        double eigtol(1.e-3);           /* */

        /* Chaco vertices are base 1 */
        for (int i = 0; i < start[iTotVertices]; i++) {
                adjacency[i]++;
        }

        /* weights = 0 are not allowed */
        std::vector<int> ivertex_weights(iTotVertices);
        if (vertex_weights) {
                for (int i = 0; i < iTotVertices; i++) {
                        /* trying to emulate communication weights? */
                        if (comm_weights) {
                                vertex_weights[i] += comm_weights[i];
                        }

                        if (vertex_weights[i] == 0) {
                                ivertex_weights[i] = 1;
                        } else {
                                ivertex_weights[i] = vertex_weights[i];
                        }
                }
        }

        /* Chaco uses floats for the communication weights */
        std::vector<float> fedge_weights(2*start[iTotVertices]);
        if (edge_weights) {
                for (int i = 0; i < iTotVertices; i++) {
                        fedge_weights[i] = edge_weights[i];
                        fedge_weights[start[iTotVertices] + i] = edge_weights[i];
                }
        }

        /* NOTE: don't free() adjacency !!! (default in Chaco 2.2) */
        if (FREE_GRAPH) {
                FREE_GRAPH = 0;
        }
        
        int rc = interface(
                        iTotVertices,           /* number of vertices in full graph */
                        start,                  /* start of edge list for each vertex */
                        adjacency,              /* edge list data */
                        vertex_weights ? &ivertex_weights[0] : 0,       /* weights for all vertices */
                        edge_weights ? &fedge_weights[0] : 0,           /* weights for all edges */
                        NULL,                   /* coordinates for inertial method */
                        NULL,                   /* ... */
                        NULL,                   /* ... */
                        NULL,                   /* name of assignment output file */
                        NULL,                   /* output file name */
                        &set_assignment[0],     /* set number of each vtx (length n) */
                        architecture,           /* 0 => hypercube, d => d-dimensional mesh */
                        num_processors,         /* total number of cube dimensions to divide */
                        mesh_dims,              /* dimensions of mesh of processors */
                        NULL,                   /* desired set sizes for each set */
                        global_method,          /* global partitioning algorithm */
                        local_method,           /* local partitioning algorithm */
                        rqi_flag,               /* should I use RQI/Symmlq eigensolver? */
                        vmax,                   /* how many vertices to coarsen down to? */
                        1,                      /* number of eigenvectors (2^d sets) */
                        eigtol,                 /* tolerance on eigenvectors */
                        seed                    /* for random graph mutations */
        );

        /* Chaco vertices are base 1 */
        for (int i = 0; i < start[iTotVertices]; i++) {
                adjacency[i]--;
        }

        if (rc != 0) {
                silent_cerr("chaco_interface(): partition failed" << std::endl);
        }

        for (int i = 0; i < iTotVertices; i++) {
                pParAmgProcs[i] = set_assignment[i];
        }
}