/*U****************************************************************************
PGARunMutationAndCrossover - Performs crossover and mutation from one
population to create the next. Assumes PGASelect has been called.
Category: Generation
Inputs:
ctx - context variable
oldpop - symbolic constant of old population
newpop - symbolic constant of new population
Outputs:
newpop is modified by side-effect.
Example:
PGAContext *ctx,
:
PGARunMutationAndCrossover(ctx, PGA_OLDPOP, PGA_NEWPOP);
****************************************************************************U*/
void PGARunMutationAndCrossover (PGAContext *ctx, int oldpop, int newpop)
{
int i, j, n, m1, m2;
int popsize, numreplace;
double pc;
PGADebugEntered("PGARunMutationAndCrossover");
popsize = PGAGetPopSize(ctx);
numreplace = PGAGetNumReplaceValue(ctx);
/*** first, copy n best strings (sorted by fitness) to new pop ***/
PGASortPop( ctx, oldpop );
n = popsize - numreplace;
for ( i=0; i < n; i++ ) {
j = PGAGetSortedPopIndex( ctx, i );
PGACopyIndividual ( ctx, j, oldpop, i, newpop );
}
pc = PGAGetCrossoverProb(ctx);
/*** reproduce to create the rest of the new population ***/
while ( n < popsize) {
m1 = PGASelectNextIndex( ctx );
m2 = PGASelectNextIndex( ctx );
if ( PGARandomFlip(ctx, pc) ) {
PGACrossover ( ctx, m1, m2, oldpop, PGA_TEMP1,
PGA_TEMP2, newpop);
/*** mutate and copy first string to new population ***/
PGAMutate ( ctx, PGA_TEMP1, newpop);
while (PGADuplicate( ctx, PGA_TEMP1, newpop, newpop, n))
PGAChange ( ctx, PGA_TEMP1, newpop );
PGACopyIndividual ( ctx, PGA_TEMP1, newpop, n, newpop);
n++;
if ( n < popsize ) {
/*** mutate and copy second string to new population ***/
PGAMutate ( ctx, PGA_TEMP2, newpop);
while ( PGADuplicate( ctx, PGA_TEMP2, newpop, newpop, n))
PGAChange ( ctx, PGA_TEMP2, newpop );
PGACopyIndividual ( ctx, PGA_TEMP2, newpop, n, newpop);
n++;
}
}
else {
PGACopyIndividual ( ctx, m1, oldpop, n, newpop );
n++;
if ( n < ctx->ga.PopSize ) {
PGACopyIndividual ( ctx, m2, oldpop, n, newpop );
n++;
}
}
}
PGADebugExited("PGARunMutationAndCrossover");
}
/* Function to muatate a PGA_DATATYPE_CHARACTER string. This is done
* by simply picking allele locations and replacing whatever was there.
* Again, legal values are all printable ASCII characters.
*/
int N_Mutation(PGAContext *ctx, int p, int pop, double mr) {
int i, count;
count = 0;
for(i=PGAGetStringLength(ctx)-1; i>=0; i--)
if (PGAGetCharacterAllele(ctx, p, pop, i) != Name[i]) {
if (PGARandomFlip(ctx, mr) == PGA_TRUE) {
PGASetCharacterAllele(ctx, p, pop, i,
PGARandomInterval(ctx, 32, 126));
count++;
}
}
return(count);
}
/* Function to crossover two name strings. Quite an interesting
* crossover, too. Works like a normal uniform crossover, except
* that, if one of the strings matches the correct value, we set
* BOTH children to the correct value 50% of the time.
*/
void N_Crossover(PGAContext *ctx, int p1, int p2, int pop1, int c1,
int c2, int pop2) {
int i, length;
char a, b;
length = PGAGetStringLength(ctx);
for (i=0; i<length; i++) {
a = PGAGetCharacterAllele(ctx, p1, pop1, i);
b = PGAGetCharacterAllele(ctx, p2, pop1, i);
if ((a == Name[i]) || (b == Name[i]))
a = b = Name[i];
if (PGARandomFlip(ctx, 0.5) == PGA_TRUE) {
PGASetCharacterAllele(ctx, c1, pop2, i, a);
PGASetCharacterAllele(ctx, c2, pop2, i, b);
} else {
PGASetCharacterAllele(ctx, c1, pop2, i, b);
PGASetCharacterAllele(ctx, c2, pop2, i, a);
}
}
}
/*U****************************************************************************
PGARunMutationOrCrossover - Performs crossover or mutation (but not both)
from one populationto create the next. Assumes PGASelect has been called.
Category: Generation
Inputs:
ctx - context variable
oldpop - symbolic constant of old population
newpop - symbolic constant of new population
Outputs:
newpop is modified by side-effect.
Example:
PGAContext *ctx,
:
PGARunMutationOrCrossover(ctx, PGA_OLDPOP, PGA_NEWPOP);
****************************************************************************U*/
void PGARunMutationOrCrossover ( PGAContext *ctx, int oldpop, int newpop )
{
int i, j, n, m1, m2;
int popsize, numreplace;
double pc;
PGADebugEntered("PGARunMutationOrCrossover");
popsize = PGAGetPopSize(ctx);
numreplace = PGAGetNumReplaceValue(ctx);
/*** first, copy n best strings (sorted by fitness) to new pop ***/
PGASortPop( ctx, oldpop );
n = popsize - numreplace;
for ( i=0; i < n; i++ ) {
j = PGAGetSortedPopIndex( ctx, i );
PGACopyIndividual ( ctx, j, oldpop, i, newpop );
}
pc = PGAGetCrossoverProb(ctx);
/*** reproduce to create the rest of the new population ***/
while ( n < popsize ) {
m1 = PGASelectNextIndex( ctx );
m2 = PGASelectNextIndex( ctx );
if ( PGARandomFlip(ctx, pc) ) {
PGACrossover ( ctx, m1, m2, oldpop, PGA_TEMP1,
PGA_TEMP2, newpop);
/*** copy first string to new population ***/
while (PGADuplicate(ctx, PGA_TEMP1, newpop, newpop, n))
PGAChange ( ctx, PGA_TEMP1, newpop );
PGACopyIndividual ( ctx, PGA_TEMP1, newpop, n, newpop);
n++;
if ( n < popsize )
{
/*** copy second string to new population ***/
while (PGADuplicate(ctx, PGA_TEMP2, newpop, newpop, n))
PGAChange ( ctx, PGA_TEMP2, newpop );
PGACopyIndividual ( ctx, PGA_TEMP2, newpop, n, newpop);
n++;
}
}
else
{
PGACopyIndividual(ctx, m1, oldpop, PGA_TEMP1, newpop);
PGAMutate ( ctx, PGA_TEMP1, newpop );
while (PGADuplicate(ctx, PGA_TEMP1, newpop, newpop, n ))
PGAChange ( ctx, PGA_TEMP1, newpop );
PGACopyIndividual ( ctx, PGA_TEMP1, newpop, n, newpop);
/* A bug of PGA ??? -- PGAChange doesn't set the UpToDateFlag,
so it won't be evaluated and gives wrong evaluation result */
PGASetEvaluationUpToDateFlag (ctx, n, newpop, PGA_FALSE);
n++;
if ( n < popsize ) {
PGACopyIndividual(ctx, m2, oldpop, PGA_TEMP2, newpop);
PGAMutate ( ctx, PGA_TEMP2, newpop );
while (PGADuplicate(ctx, PGA_TEMP2, newpop, newpop, n ))
PGAChange ( ctx, PGA_TEMP2, newpop );
PGACopyIndividual ( ctx, PGA_TEMP2, newpop, n, newpop);
PGASetEvaluationUpToDateFlag (ctx, n, newpop, PGA_FALSE);
n++;
}
}
}
PGADebugExited("PGARunMutationOrCrossover");
}
