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82 lines
2.9 KiB
82 lines
2.9 KiB
/*
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* Copyright(C) 1999-2020 National Technology & Engineering Solutions
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* of Sandia, LLC (NTESS). Under the terms of Contract DE-NA0003525 with
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* NTESS, the U.S. Government retains certain rights in this software.
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*
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* See packages/seacas/LICENSE for details
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*/
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#include "smalloc.h" // for sfree, smalloc
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#include "structs.h" // for vtx_data
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#include <stdio.h> // for NULL, printf
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static float *old_ewgts; /* space for old edge weights */
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void compress_ewgts(struct vtx_data **graph, /* list of graph info for each vertex */
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int nvtxs, /* number of vertices in graph */
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int nedges, /* number of edges in graph */
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double ewgt_max, /* largest edge weight */
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int using_ewgts /* are edge weights being used? */
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)
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{
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extern double EWGT_RATIO_MAX; /* max allowed ewgt/nvtxs */
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float * old_ewptr; /* loops through old edge weights */
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float * new_ewptr; /* loops through old edge weights */
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float * self_ptr; /* points to self edge in new_ewgts */
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float * new_ewgts; /* space for new edge weights */
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int ewgt; /* new edge weight value */
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double sum; /* sum of all the new edge weights */
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double ratio; /* amount to reduce edge weights */
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int i, j; /* loop counter */
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/* Check easy cases first. */
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if (!using_ewgts) {
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old_ewgts = NULL;
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}
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else if (ewgt_max < EWGT_RATIO_MAX * nvtxs) {
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/* If not too heavy, leave it alone. */
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old_ewgts = NULL;
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printf("In compress_ewgts, but not too heavy, ewgt_max = %g, nvtxs = %d\n", ewgt_max, nvtxs);
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}
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else { /* Otherwise, compress edge weights. */
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/* Allocate space for new edge weights */
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old_ewgts = graph[1]->ewgts;
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new_ewgts = smalloc((2 * nedges + nvtxs) * sizeof(float));
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ratio = (EWGT_RATIO_MAX * nvtxs) / ewgt_max;
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printf("In compress_ewgts, ewgt_max = %g, nvtxs = %d, ratio = %e\n", ewgt_max, nvtxs, ratio);
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old_ewptr = old_ewgts;
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new_ewptr = new_ewgts;
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for (i = 1; i <= nvtxs; i++) {
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self_ptr = new_ewptr++;
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old_ewptr++;
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sum = 0;
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for (j = graph[i]->nedges - 1; j; j--) {
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ewgt = (int)(*(old_ewptr++) * ratio + 1.0);
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*(new_ewptr++) = (float)ewgt;
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sum += (float)ewgt;
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}
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*self_ptr = -sum;
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graph[i]->ewgts = self_ptr;
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}
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}
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}
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void restore_ewgts(struct vtx_data **graph, /* list of graph info for each vertex */
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int nvtxs /* number of vertices in graph */
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)
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{
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int i; /* loop counter */
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/* Check easy case first. */
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if (old_ewgts == NULL) {
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return;
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}
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/* otherwise, compress edge weights. */
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sfree(graph[1]->ewgts);
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for (i = 1; i <= nvtxs; i++) {
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graph[i]->ewgts = old_ewgts;
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old_ewgts += graph[i]->nedges;
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}
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old_ewgts = NULL;
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}
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