public int produce(
final int min,
final int max,
final int start,
final int subpopulation,
final Individual[] inds,
final EvolutionState state,
final int thread) {
// how many individuals should we make?
int n = typicalIndsProduced();
if (n < min) n = min;
if (n > max) n = max;
// should we bother?
if (!state.random[thread].nextBoolean(likelihood))
return reproduce(
n,
start,
subpopulation,
inds,
state,
thread,
true); // DO produce children from source -- we've not done so already
GPInitializer initializer = ((GPInitializer) state.initializer);
for (int q = start; q < n + start; /* no increment */ ) // keep on going until we're filled up
{
// grab two individuals from our sources
if (sources[0] == sources[1]) // grab from the same source
sources[0].produce(2, 2, 0, subpopulation, parents, state, thread);
else // grab from different sources
{
sources[0].produce(1, 1, 0, subpopulation, parents, state, thread);
sources[1].produce(1, 1, 1, subpopulation, parents, state, thread);
}
// at this point, parents[] contains our two selected individuals
// are our tree values valid?
if (tree1 != TREE_UNFIXED && (tree1 < 0 || tree1 >= parents[0].trees.length))
// uh oh
state.output.fatal(
"GP Crossover Pipeline attempted to fix tree.0 to a value which was out of bounds of the array of the individual's trees. Check the pipeline's fixed tree values -- they may be negative or greater than the number of trees in an individual");
if (tree2 != TREE_UNFIXED && (tree2 < 0 || tree2 >= parents[1].trees.length))
// uh oh
state.output.fatal(
"GP Crossover Pipeline attempted to fix tree.1 to a value which was out of bounds of the array of the individual's trees. Check the pipeline's fixed tree values -- they may be negative or greater than the number of trees in an individual");
int t1 = 0;
int t2 = 0;
if (tree1 == TREE_UNFIXED || tree2 == TREE_UNFIXED) {
do
// pick random trees -- their GPTreeConstraints must be the same
{
if (tree1 == TREE_UNFIXED)
if (parents[0].trees.length > 1)
t1 = state.random[thread].nextInt(parents[0].trees.length);
else t1 = 0;
else t1 = tree1;
if (tree2 == TREE_UNFIXED)
if (parents[1].trees.length > 1)
t2 = state.random[thread].nextInt(parents[1].trees.length);
else t2 = 0;
else t2 = tree2;
} while (parents[0].trees[t1].constraints(initializer)
!= parents[1].trees[t2].constraints(initializer));
} else {
t1 = tree1;
t2 = tree2;
// make sure the constraints are okay
if (parents[0].trees[t1].constraints(initializer)
!= parents[1].trees[t2].constraints(initializer)) // uh oh
state.output.fatal(
"GP Crossover Pipeline's two tree choices are both specified by the user -- but their GPTreeConstraints are not the same");
}
// validity results...
boolean res1 = false;
boolean res2 = false;
// prepare the nodeselectors
nodeselect1.reset();
nodeselect2.reset();
// pick some nodes
GPNode p1 = null;
GPNode p2 = null;
for (int x = 0; x < numTries; x++) {
// pick a node in individual 1
p1 = nodeselect1.pickNode(state, subpopulation, thread, parents[0], parents[0].trees[t1]);
// pick a node in individual 2
p2 = nodeselect2.pickNode(state, subpopulation, thread, parents[1], parents[1].trees[t2]);
// check for depth and swap-compatibility limits
res1 = verifyPoints(initializer, p2, p1); // p2 can fill p1's spot -- order is important!
if (n - (q - start) < 2 || tossSecondParent) res2 = true;
else
res2 = verifyPoints(initializer, p1, p2); // p1 can fill p2's spot -- order is important!
// did we get something that had both nodes verified?
// we reject if EITHER of them is invalid. This is what lil-gp does.
// Koza only has numTries set to 1, so it's compatible as well.
if (res1 && res2) break;
}
// at this point, res1 AND res2 are valid, OR either res1
// OR res2 is valid and we ran out of tries, OR neither is
// valid and we ran out of tries. So now we will transfer
// to a tree which has res1 or res2 valid, otherwise it'll
// just get replicated. This is compatible with both Koza
// and lil-gp.
// at this point I could check to see if my sources were breeding
// pipelines -- but I'm too lazy to write that code (it's a little
// complicated) to just swap one individual over or both over,
// -- it might still entail some copying. Perhaps in the future.
// It would make things faster perhaps, not requiring all that
// cloning.
// Create some new individuals based on the old ones -- since
// GPTree doesn't deep-clone, this should be just fine. Perhaps we
// should change this to proto off of the main species prototype, but
// we have to then copy so much stuff over; it's not worth it.
GPIndividual j1 = (GPIndividual) (parents[0].lightClone());
GPIndividual j2 = null;
if (n - (q - start) >= 2 && !tossSecondParent) j2 = (GPIndividual) (parents[1].lightClone());
// Fill in various tree information that didn't get filled in there
j1.trees = new GPTree[parents[0].trees.length];
if (n - (q - start) >= 2 && !tossSecondParent) j2.trees = new GPTree[parents[1].trees.length];
// at this point, p1 or p2, or both, may be null.
// If not, swap one in. Else just copy the parent.
for (int x = 0; x < j1.trees.length; x++) {
if (x == t1 && res1) // we've got a tree with a kicking cross position!
{
j1.trees[x] = (GPTree) (parents[0].trees[x].lightClone());
j1.trees[x].owner = j1;
j1.trees[x].child = parents[0].trees[x].child.cloneReplacing(p2, p1);
j1.trees[x].child.parent = j1.trees[x];
j1.trees[x].child.argposition = 0;
j1.evaluated = false;
} // it's changed
else {
j1.trees[x] = (GPTree) (parents[0].trees[x].lightClone());
j1.trees[x].owner = j1;
j1.trees[x].child = (GPNode) (parents[0].trees[x].child.clone());
j1.trees[x].child.parent = j1.trees[x];
j1.trees[x].child.argposition = 0;
}
}
if (n - (q - start) >= 2 && !tossSecondParent)
for (int x = 0; x < j2.trees.length; x++) {
if (x == t2 && res2) // we've got a tree with a kicking cross position!
{
j2.trees[x] = (GPTree) (parents[1].trees[x].lightClone());
j2.trees[x].owner = j2;
j2.trees[x].child = parents[1].trees[x].child.cloneReplacing(p1, p2);
j2.trees[x].child.parent = j2.trees[x];
j2.trees[x].child.argposition = 0;
j2.evaluated = false;
} // it's changed
else {
j2.trees[x] = (GPTree) (parents[1].trees[x].lightClone());
j2.trees[x].owner = j2;
j2.trees[x].child = (GPNode) (parents[1].trees[x].child.clone());
j2.trees[x].child.parent = j2.trees[x];
j2.trees[x].child.argposition = 0;
}
}
// add the individuals to the population
inds[q] = j1;
q++;
if (q < n + start && !tossSecondParent) {
inds[q] = j2;
q++;
}
}
return n;
}
