public int chooseTerminalSymbol(EvolutionState state, int thread) {
int terminalChoice =
RandomChoice.pickFromDistribution(
cumulativeNormalizedTerminalWeights, state.random[thread].nextFloat(), CHECK_BOUNDARY);
// the value returned is the function index from 0 to number of functions ...
// need to get the index into the set of symbols
return terminals[terminalChoice];
}
public GPNode newRootedTree(
final EvolutionState state,
GPType type,
final int thread,
final GPNodeParent parent,
final GPFunctionSet set,
final int argposition,
int requestedSize) {
// ptc2 can mess up if there are no available terminals for a given type. If this occurs,
// and we find ourselves unable to pick a terminal when we want to do so, we will issue a
// warning,
// and pick a nonterminal, violating the ptc2 size and depth contracts. This can lead to
// pathological situations
// where the system will continue to go on and on unable to stop because it can't pick a
// terminal,
// resulting in running out of memory or some such. But there are cases where we'd want to let
// this work itself out.
boolean triedTerminals = false;
if (!(set instanceof PTCFunctionSetForm))
state.output.fatal(
"Set "
+ set.name
+ " is not of the class ec.gp.build.PTCFunctionSetForm, and so cannot be used with PTC Nodebuilders.");
PTCFunctionSetForm pset = (PTCFunctionSetForm) set;
// pick a size from the distribution
if (requestedSize == NOSIZEGIVEN) requestedSize = pickSize(state, thread);
GPNode root;
int t = type.type;
GPNode[] terminals = set.terminals[t];
GPNode[] nonterminals = set.nonterminals[t];
GPNode[] nodes = set.nodes[t];
if (nodes.length == 0) errorAboutNoNodeWithType(type, state); // total failure
// return a terminal
if ((requestedSize == 1
|| // Now pick a terminal if our size is 1
warnAboutNonterminal(nonterminals.length == 0, type, false, state))
&& // OR if there are NO nonterminals!
(triedTerminals = true)
&& // [first set triedTerminals]
terminals.length != 0) // AND if there are available terminals
{
root =
(GPNode)
terminals[
RandomChoice.pickFromDistribution(
pset.terminalProbabilities(t),
state.random[thread].nextFloat(),
CHECK_BOUNDARY)]
.lightClone();
root.resetNode(state, thread); // give ERCs a chance to randomize
root.argposition = (byte) argposition;
root.parent = parent;
} else // return a nonterminal-rooted tree
{
if (triedTerminals)
warnAboutNoTerminalWithType(
type, false, state); // we tried terminals and we're here because there were none!
// pick a nonterminal
root =
(GPNode)
nonterminals[
RandomChoice.pickFromDistribution(
pset.nonterminalProbabilities(t),
state.random[thread].nextFloat(),
CHECK_BOUNDARY)]
.lightClone();
root.resetNode(state, thread); // give ERCs a chance to randomize
root.argposition = (byte) argposition;
root.parent = parent;
// set the depth, size, and enqueuing, and reset the random dequeue
s_size = 0; // pretty critical!
int s = 1;
GPInitializer initializer = ((GPInitializer) state.initializer);
GPType[] childtypes = root.constraints(initializer).childtypes;
for (int x = 0; x < childtypes.length; x++) enqueue(root, x, 1); /* depth 1 */
while (s_size > 0) {
triedTerminals = false;
randomDequeue(state, thread);
type = dequeue_node.constraints(initializer).childtypes[dequeue_argpos];
int y = type.type;
terminals = set.terminals[y];
nonterminals = set.nonterminals[y];
nodes = set.nodes[y];
if (nodes.length == 0) errorAboutNoNodeWithType(type, state); // total failure
// pick a terminal
if ((s_size + s >= requestedSize
|| // if we need no more nonterminal nodes
dequeue_depth == maxDepth
|| // OR if we're at max depth and must pick a terminal
warnAboutNonterminal(nonterminals.length == 0, type, false, state))
&& // OR if there are NO nonterminals!
(triedTerminals = true)
&& // [first set triedTerminals]
terminals.length != 0) // AND if there are available terminals
{
GPNode n =
(GPNode)
terminals[
RandomChoice.pickFromDistribution(
pset.terminalProbabilities(y),
state.random[thread].nextFloat(),
CHECK_BOUNDARY)]
.lightClone();
dequeue_node.children[dequeue_argpos] = n;
n.resetNode(state, thread); // give ERCs a chance to randomize
n.argposition = (byte) dequeue_argpos;
n.parent = dequeue_node;
}
// pick a nonterminal and enqueue its children
else {
if (triedTerminals)
warnAboutNoTerminalWithType(
type, false, state); // we tried terminals and we're here because there were none!
GPNode n =
(GPNode)
nonterminals[
RandomChoice.pickFromDistribution(
pset.nonterminalProbabilities(y),
state.random[thread].nextFloat(),
CHECK_BOUNDARY)]
.lightClone();
dequeue_node.children[dequeue_argpos] = n;
n.resetNode(state, thread); // give ERCs a chance to randomize
n.argposition = (byte) dequeue_argpos;
n.parent = dequeue_node;
childtypes = n.constraints(initializer).childtypes;
for (int x = 0; x < childtypes.length; x++) enqueue(n, x, dequeue_depth + 1);
}
s++;
}
}
return root;
}