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/*
NETGEN -- Copyright 1989, Massimo A. Sivilotti, Caltech
*/
#include "config.h"
#include <stdio.h>
#include <math.h>
#include "hash.h"
#include "objlist.h"
#include "embed.h"
#include "timing.h"
#include "print.h"
#include "dbug.h"
int MaxCPUTime = 100; /* max number of seconds to burn */
#define MAX_SIM_ANNEAL_ITER 10
#define MAX_CHANGES_PER_ITER 2
#if 0
float RandomUniform(void)
{
/* DANGER! DANGER! Non-portable code below!! */
return ((float)(rand()) / ((1<<15) - 1.0));
}
#endif
int GenerateAnnealPartition(int left, int right, int level)
/* tries to find a balanced partition, as far as leaf cell usage */
{
int i;
int IncludedElements, partition;
int ChangesMade, Iterations;
int leftfanout, rightfanout;
float T;
level++; /* just to keep to compiler from whining about unused parameter */
IncludedElements = (right - left) / 2;
partition = left + IncludedElements - 1;
/* don't actually use {left,right}fanout, but need to
initialize leftnodes and rightnodes arrays */
leftfanout = PartitionFanout(left, partition, LEFT);
rightfanout = PartitionFanout(partition + 1, right, RIGHT);
#if 0
/* someday, need an escape clause here */
if (leftfanout <= TreeFanout[level] && rightfanout <= TreeFanout[level])
return(partition);
#endif
Printf("called generateannealpartition with left = %d, right = %d\n",left,right);
/* actually do the annealing now */
T = 3.0;
do {
int el1, el2;
int delta;
Iterations = 0;
ChangesMade = 0;
do {
el1 = Random(partition - left + 1) + left;
el2 = Random(right - partition) + partition + 1;
Iterations++;
delta = 0;
for (i = 1; i <= Nodes; i++) {
/* could do the following test with XOR */
if (CSTAR[permutation[el1]][i] == 0 && CSTAR[permutation[el2]][i] == 0)
continue;
if (CSTAR[permutation[el1]][i] != 0 && CSTAR[permutation[el2]][i] != 0)
continue;
/* only one of these is non-zero */
if (CSTAR[permutation[el1]][i] != 0) {
if (rightnodes[i] == 0) {
/* things are not good unless all the fanout is captured in el1 */
if (CSTAR[permutation[el1]][i] != leftnodes[i]) delta++;
}
else {
/* things are good if all fanout is captured in el1 */
if (CSTAR[permutation[el1]][i] == leftnodes[i]) delta--;
}
}
else {
if (leftnodes[i] == 0) {
/* things are not good unless all the fanout is captured in el2 */
if (CSTAR[permutation[el2]][i] != rightnodes[i]) delta++;
}
else {
/* things are good if all fanout is captured in el2 */
if (CSTAR[permutation[el2]][i] == rightnodes[i]) delta--;
}
}
}
DBUG_EXECUTE("place",
Printf("\n");
Printf("considering swapping %d and %d\n",permutation[el1],permutation[el2]);
Printf("E1: ");
for (i = 1; i <= Nodes; i++) Printf("%2d ",CSTAR[permutation[el1]][i]);
Printf("\nL: ");
for (i = 1; i <= Nodes; i++) Printf("%2d ",leftnodes[i]);
Printf("\nE2: ");
for (i = 1; i <= Nodes; i++) Printf("%2d ",CSTAR[permutation[el2]][i]);
Printf("\nR: ");
for (i = 1; i <= Nodes; i++) Printf("%2d ",rightnodes[i]);
Printf("\nC0: ");
for (i = 1; i <= Nodes; i++) Printf("%2d ",CSTAR[0][i]);
Printf("\ndelta = %d\n", delta);
);
if (delta < 0 || exp(-delta / T) > RandomUniform()) {
int tmp;
if (delta < 0) ChangesMade++;
/* update the {left, right}nodes arrays */
for (i = 1; i <= Nodes; i++) {
leftnodes[i] +=
CSTAR[permutation[el2]][i] - CSTAR[permutation[el1]][i];
rightnodes[i] -=
CSTAR[permutation[el2]][i] - CSTAR[permutation[el1]][i];
}
/* now swap the elements */
DBUG_EXECUTE("place",
Printf("swapping elements %d and %d\n",
permutation[el1],permutation[el2]);
);
tmp = permutation[el1];
permutation[el1] = permutation[el2];
permutation[el2] = tmp;
}
} while (ChangesMade <= MAX_CHANGES_PER_ITER &&
Iterations < MAX_SIM_ANNEAL_ITER);
T = 0.90 * T;
Printf("decreasing T to %.2f after %d iterations.\n",T,Iterations);
} while (ChangesMade > 0);
return (partition);
}
int AnnealPartition(int left, int right, int level)
/* return index of new element, if successful partition has been found */
{
int partition;
int iterations;
int found;
int OriginalNewN;
int leftelement, rightelement;
#define MAX_PARTITION_ITERATIONS 10
DBUG_ENTER("AnnealPartition");
OriginalNewN = NewN;
if (level < LEVEL(permutation[left])) {
Fprintf(stdout,"Failed at level %d; subtree too deep\n",level);
DBUG_RETURN(0);
}
if (left == right) DBUG_RETURN(permutation[left]);
if (right - left == 1) {
/* don't bother annealing, just add it to the list */
AddNewElement(permutation[left], permutation[right]);
DBUG_RETURN(NewN);
}
/* use simulated annealing to gather about 1/2 of the elements,
Then check to see if it is valid.
*/
DBUG_PRINT("place",("trying to partition %d, %d",left,right));
iterations = 0;
do {
int i;
int leftfanout, rightfanout;
iterations++;
partition = GenerateAnnealPartition(left, right, level);
if (partition == 0) DBUG_RETURN(0); /* no valid partition */
found = 0;
leftfanout = PartitionFanout(left,partition,LEFT);
rightfanout = PartitionFanout(partition+1, right, RIGHT);
if (leftfanout <= TreeFanout[level] && rightfanout <= TreeFanout[level])
found = 1;
if (!found || level > TopDownStartLevel - 2) {
for (i = MAX_TREE_DEPTH; i > level; i--) Fprintf(stdout, " ");
Fprintf(stdout,
"Level: %d; L (%d leaves) fanout %d; R (%d leaves) fanout %d (<= %d) %s\n",
level, (partition - left + 1), leftfanout,
(right - partition), rightfanout, TreeFanout[level],
found ? "SUCCESSFUL" : "UNSUCCESSFUL");
}
#if 0
if (!found) {
int IterationLimit;
for (IterationLimit = 0; IterationLimit < 20 &&
GradientDescent(left, right, partition); IterationLimit++);
found = 0;
leftfanout = PartitionFanout(left,partition,LEFT);
rightfanout = PartitionFanout(partition+1, right, RIGHT);
if (leftfanout <= TreeFanout[level] && rightfanout <= TreeFanout[level])
found = 1;
for (i = MAX_TREE_DEPTH; i > level; i--) Fprintf(stdout, " ");
Fprintf(stdout,
" Iteration %2d: L fanout %d; R fanout %d (<= %d) %s\n",
iterations, leftfanout, rightfanout, TreeFanout[level],
found ? "SUCCESSFUL" : "UNSUCCESSFUL");
}
#endif
DBUG_EXECUTE("place",
Fprintf(DBUG_FILE,"Level %d: ",level);
Dbug_print_cells(left,partition);
Dbug_print_cells(partition+1,right);
Fprintf(DBUG_FILE,"\n");
{
int i;
Fprintf(DBUG_FILE,"L ");
for (i = 1; i <= Nodes; i++)
Fprintf(DBUG_FILE,"%2d ",leftnodes[i]);
Fprintf(DBUG_FILE,"\nR ");
for (i = 1; i <= Nodes; i++)
Fprintf(DBUG_FILE,"%2d ",rightnodes[i]);
Fprintf(DBUG_FILE,"\n");
}
Fprintf(DBUG_FILE, "%s\n", found?"SUCCESSFUL":"UNSUCCESSFUL");
);
} while (iterations < MAX_PARTITION_ITERATIONS && !found);
if (!found) {
Fprintf(stdout,"Failed embedding at level %d; no partition\n",level);
goto fail;
}
leftelement = AnnealPartition(left, partition, level-1);
if (leftelement == 0) goto fail;
rightelement = AnnealPartition(partition+1, right, level-1);
if (rightelement == 0) goto fail;
/* add it to the list */
AddNewElement(leftelement, rightelement);
DBUG_RETURN(NewN);
fail:
NewN = OriginalNewN;
DBUG_RETURN(0);
}
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