LloydSmoother.cpp

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#include "moab/LloydSmoother.hpp"
#include "moab/Skinner.hpp"
#include "moab/CN.hpp"
#include "moab/CartVect.hpp"
#include "moab/BoundBox.hpp"
 
#ifdef MOAB_HAVE_MPI
#include "moab/ParallelComm.hpp"
#include "MBParallelConventions.h"
#endif
 
#include <iostream>
 
namespace moab
{
 
LloydSmoother::LloydSmoother( Interface* impl, ParallelComm* pc, Range& elms, Tag ctag, Tag ftag, double at, double rt )
 : mbImpl( impl ), myPcomm( pc ), myElems( elms ), coordsTag( ctag ), fixedTag( ftag ), absTol( at ), relTol( rt ),
 reportIts( 0 ), numIts( 0 ), iCreatedTag( false )
{
}
 
LloydSmoother::~LloydSmoother()
{
 if( iCreatedTag && fixedTag )
 {
 ErrorCode rval = mbImpl->tag_delete( fixedTag );MB_CHK_SET_ERR_RET( rval, "Failed to delete the fixed tag" );
 }
}
 
ErrorCode LloydSmoother::perform_smooth()
{
 ErrorCode rval;
 
 if( myElems.empty() )
 {
 MB_SET_ERR( MB_FAILURE, "No elements specified to Lloyd smoother" );
 }
 else if( mbImpl->dimension_from_handle( *myElems.begin() ) != mbImpl->dimension_from_handle( *myElems.rbegin() ) )
 {
 MB_SET_ERR( MB_FAILURE, "Elements of unequal dimension specified to Lloyd smoother" );
 }
 
 int dim = mbImpl->dimension_from_handle( *myElems.begin() );
 
 // first figure out tolerance to use
 if( 0 > absTol )
 {
 // no tolerance set - get one relative to bounding box around elements
 BoundBox bb;
 rval = bb.update( *mbImpl, myElems );MB_CHK_SET_ERR( rval, "Failed to compute bounding box around elements" );
 absTol = relTol * bb.diagonal_length();
 }
 
 // initialize if we need to
 rval = initialize();MB_CHK_SET_ERR( rval, "Failed to initialize" );
 
 // get all vertices
 Range verts;
 rval = mbImpl->get_adjacencies( myElems, 0, false, verts, Interface::UNION );MB_CHK_SET_ERR( rval, "Failed to get all vertices" );
 
 // perform Lloyd relaxation:
 // 1. setup: set vertex centroids from vertex coords; filter to owned verts; get fixed tags
 
 // get all verts coords into tag; don't need to worry about filtering out fixed verts,
 // we'll just be setting to their fixed coords
 std::vector< double > vcentroids( 3 * verts.size() );
 if( !coordsTag )
 {
 rval = mbImpl->get_coords( verts, &vcentroids[0] );MB_CHK_SET_ERR( rval, "Failed to get vert coords" );
 }
 else
 {
 rval = mbImpl->tag_get_data( coordsTag, verts, &vcentroids[0] );MB_CHK_SET_ERR( rval, "Failed to get vert coords tag values" );
 }
 
 Tag centroid;
 rval = mbImpl->tag_get_handle( "", 3, MB_TYPE_DOUBLE, centroid, MB_TAG_CREAT | MB_TAG_DENSE );MB_CHK_SET_ERR( rval, "Couldn't get tag handle" );
 rval = mbImpl->tag_set_data( centroid, verts, &vcentroids[0] );MB_CHK_SET_ERR( rval, "Failed setting centroid tag" );
 
 Range owned_verts, shared_owned_verts;
#ifdef MOAB_HAVE_MPI
 // filter verts down to owned ones and get fixed tag for them
 if( myPcomm && myPcomm->size() > 1 )
 {
 rval = myPcomm->filter_pstatus( verts, PSTATUS_NOT_OWNED, PSTATUS_NOT, -1, &owned_verts );MB_CHK_SET_ERR( rval, "Failed to filter on pstatus" );
 // get shared owned verts, for exchanging tags
 rval = myPcomm->filter_pstatus( owned_verts, PSTATUS_SHARED, PSTATUS_AND, -1, &shared_owned_verts );MB_CHK_SET_ERR( rval, "Failed to filter for shared owned" );
 // workaround: if no shared owned verts, put a non-shared one in the list, to prevent
 // exchanging tags for all shared entities
 if( shared_owned_verts.empty() ) shared_owned_verts.insert( *verts.begin() );
 }
 else
 owned_verts = verts;
#else
 owned_verts = verts;
#endif
 
 std::vector< unsigned char > fix_tag( owned_verts.size() );
 rval = mbImpl->tag_get_data( fixedTag, owned_verts, &fix_tag[0] );MB_CHK_SET_ERR( rval, "Failed to get fixed tag" );
 
 // now fill vcentroids array with positions of just owned vertices, since those are the ones
 // we're actually computing
 vcentroids.resize( 3 * owned_verts.size() );
 rval = mbImpl->tag_get_data( centroid, owned_verts, &vcentroids[0] );MB_CHK_SET_ERR( rval, "Failed to get centroid tag" );
 
 // some declarations for later iterations
 std::vector< double > fcentroids( 3 * myElems.size() ); // fcentroids for element centroids
 std::vector< double > ctag(
 3 * CN::MAX_NODES_PER_ELEMENT ); // temporary coordinate storage for verts bounding an element
 const EntityHandle* conn; // const ptr & size to elem connectivity
 int nconn;
 Range::iterator eit, vit; // for iterating over elems, verts
 int e, v; // for indexing into centroid vectors
 std::vector< EntityHandle > adj_elems; // used in vertex iteration
 
 // 2. while !converged
 double resid = DBL_MAX;
 numIts = 0;
 while( resid > absTol )
 {
 numIts++;
 resid = 0.0;
 
 // 2a. foreach elem: centroid = sum(vertex centroids)/num_verts_in_cell
 for( eit = myElems.begin(), e = 0; eit != myElems.end(); ++eit, e++ )
 {
 // get verts for this elem
 rval = mbImpl->get_connectivity( *eit, conn, nconn );MB_CHK_SET_ERR( rval, "Failed to get connectivity" );
 // get centroid tags for those verts
 rval = mbImpl->tag_get_data( centroid, conn, nconn, &ctag[0] );MB_CHK_SET_ERR( rval, "Failed to get centroid" );
 fcentroids[3 * e + 0] = fcentroids[3 * e + 1] = fcentroids[3 * e + 2] = 0.0;
 for( v = 0; v < nconn; v++ )
 {
 fcentroids[3 * e + 0] += ctag[3 * v + 0];
 fcentroids[3 * e + 1] += ctag[3 * v + 1];
 fcentroids[3 * e + 2] += ctag[3 * v + 2];
 }
 for( v = 0; v < 3; v++ )
 fcentroids[3 * e + v] /= nconn;
 }
 rval = mbImpl->tag_set_data( centroid, myElems, &fcentroids[0] );MB_CHK_SET_ERR( rval, "Failed to set elem centroid" );
 
 // 2b. foreach owned vertex:
 for( vit = owned_verts.begin(), v = 0; vit != owned_verts.end(); ++vit, v++ )
 {
 // if !fixed
 if( fix_tag[v] ) continue;
 // vertex centroid = sum(cell centroids)/ncells
 adj_elems.clear();
 rval = mbImpl->get_adjacencies( &( *vit ), 1, dim, false, adj_elems );MB_CHK_SET_ERR( rval, "Failed getting adjs" );
 rval = mbImpl->tag_get_data( centroid, &adj_elems[0], adj_elems.size(), &fcentroids[0] );MB_CHK_SET_ERR( rval, "Failed to get elem centroid" );
 double vnew[] = { 0.0, 0.0, 0.0 };
 for( e = 0; e < (int)adj_elems.size(); e++ )
 {
 vnew[0] += fcentroids[3 * e + 0];
 vnew[1] += fcentroids[3 * e + 1];
 vnew[2] += fcentroids[3 * e + 2];
 }
 for( e = 0; e < 3; e++ )
 vnew[e] /= adj_elems.size();
 double delta = ( CartVect( vnew ) - CartVect( &vcentroids[3 * v] ) ).length();
 resid = ( v ? std::max( resid, delta ) : delta );
 for( e = 0; e < 3; e++ )
 vcentroids[3 * v + e] = vnew[e];
 }
 
 // set the centroid tag; having them only in vcentroids array isn't enough, as vertex
 // centroids are accessed randomly in loop over faces
 rval = mbImpl->tag_set_data( centroid, owned_verts, &vcentroids[0] );MB_CHK_SET_ERR( rval, "Failed to set vertex centroid" );
 
#ifdef MOAB_HAVE_MPI
 // 2c. exchange tags on owned verts
 if( myPcomm && myPcomm->size() > 1 )
 {
 rval = myPcomm->exchange_tags( centroid, shared_owned_verts );MB_CHK_SET_ERR( rval, "Failed to exchange tags" );
 }
#endif
 
 if( reportIts && !( numIts % reportIts ) )
 {
 double global_max = resid;
#ifdef MOAB_HAVE_MPI
 // global reduce for maximum delta, then report it
 if( myPcomm && myPcomm->size() > 1 )
 MPI_Reduce( &resid, &global_max, 1, MPI_DOUBLE, MPI_MAX, 0, myPcomm->comm() );
 if( !myPcomm || !myPcomm->rank() )
#endif
 std::cout << "Max residual = " << global_max << std::endl;
 }
 
 } // end while
 
 // write the tag back onto vertex coordinates
 if( !coordsTag )
 {
 rval = mbImpl->set_coords( owned_verts, &vcentroids[0] );MB_CHK_SET_ERR( rval, "Failed to set vertex coords" );
 }
 else
 {
 rval = mbImpl->tag_set_data( coordsTag, owned_verts, &vcentroids[0] );MB_CHK_SET_ERR( rval, "Failed to set vert coords tag values" );
 }
 
 return MB_SUCCESS;
}
 
ErrorCode LloydSmoother::initialize()
{
 ErrorCode rval = MB_SUCCESS;
 
 // first, check for tag; if we don't have it, make one and mark skin as fixed
 if( !fixedTag )
 {
 unsigned char fixed = 0x0;
 rval = mbImpl->tag_get_handle( "", 1, MB_TYPE_OPAQUE, fixedTag, MB_TAG_DENSE | MB_TAG_CREAT, &fixed );MB_CHK_SET_ERR( rval, "Trouble making fixed tag" );
 iCreatedTag = true;
 
 // get the skin; get facets, because we might need to filter on shared entities
 Skinner skinner( mbImpl );
 Range skin, skin_verts;
 rval = skinner.find_skin( 0, myElems, false, skin );MB_CHK_SET_ERR( rval, "Unable to find skin" );
 
#ifdef MOAB_HAVE_MPI
 // need to do a little extra if we're working in parallel
 if( myPcomm )
 {
 // filter out ghost and interface facets
 rval = myPcomm->filter_pstatus( skin, PSTATUS_GHOST | PSTATUS_INTERFACE, PSTATUS_NOT );MB_CHK_SET_ERR( rval, "Failed to filter on shared status" );
 }
#endif
 // get the vertices from those entities
 rval = mbImpl->get_adjacencies( skin, 0, false, skin_verts, Interface::UNION );MB_CHK_SET_ERR( rval, "Trouble getting vertices" );
 
 // mark them fixed
 std::vector< unsigned char > marks( skin_verts.size(), 0x1 );
 rval = mbImpl->tag_set_data( fixedTag, skin_verts, &marks[0] );MB_CHK_SET_ERR( rval, "Unable to set tag on skin" );
 }
 
 return MB_SUCCESS;
}
 
} // namespace moab