/*
* Encog(tm) Core v3.4 - Java Version
* http://www.heatonresearch.com/encog/
* https://github.com/encog/encog-java-core
* Copyright 2008-2016 Heaton Research, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* For more information on Heaton Research copyrights, licenses
* and trademarks visit:
* http://www.heatonresearch.com/copyright
*/
package org.encog.ml.prg.extension;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.encog.ml.ea.exception.EACompileError;
import org.encog.ml.prg.EncogProgram;
import org.encog.ml.prg.EncogProgramContext;
import org.encog.ml.prg.ProgramNode;
import org.encog.ml.prg.expvalue.ValueType;
/**
* A function factory maps the opcodes contained in the EncogOpcodeRegistry into
* an EncogProgram. You rarely want to train with every available opcode. For
* example, if you are only looking to produce an equation, you should not make
* use of the if-statement and logical operators.
*/
public class FunctionFactory implements Serializable {
/**
* The serial id.
*/
private static final long serialVersionUID = 1L;
/**
* A map for quick lookup.
*/
private final Map templateMap = new HashMap();
/**
* The opcodes.
*/
private final List opcodes = new ArrayList();
/**
* Default constructor.
*/
public FunctionFactory() {
}
/**
* Add an opcode to the function factory. The opcode must exist in the
* opcode registry.
*
* @param ext
* The opcode to add.
*/
public void addExtension(final ProgramExtensionTemplate ext) {
addExtension(ext.getName(), ext.getChildNodeCount());
}
/**
* Add an opcode to the function factory from the opcode registry.
*
* @param name
* The name of the opcode.
* @param args
* The number of arguments.
*/
public void addExtension(final String name, final int args) {
final String key = EncogOpcodeRegistry.createKey(name, args);
if (!this.templateMap.containsKey(key)) {
final ProgramExtensionTemplate temp = EncogOpcodeRegistry.INSTANCE
.findOpcode(name, args);
if (temp == null) {
throw new EACompileError("Unknown extension " + name + " with "
+ args + " arguments.");
}
this.opcodes.add(temp);
this.templateMap.put(key, temp);
}
}
/**
* Factor a new program node, based in a template object.
*
* @param temp
* The opcode.
* @param program
* The program.
* @param args
* The arguments for this node.
* @return The newly created ProgramNode.
*/
public ProgramNode factorProgramNode(final ProgramExtensionTemplate temp,
final EncogProgram program, final ProgramNode[] args) {
return new ProgramNode(program, temp, args);
}
/**
* Factor a new program node, based on an opcode name and arguments.
*
* @param name
* The name of the opcode.
* @param program
* The program to factor for.
* @param args
* The arguements.
* @return The newly created ProgramNode.
*/
public ProgramNode factorProgramNode(final String name,
final EncogProgram program, final ProgramNode[] args) {
final String key = EncogOpcodeRegistry.createKey(name, args.length);
if (!this.templateMap.containsKey(key)) {
throw new EACompileError("Undefined function/operator: " + name
+ " with " + args.length + " args.");
}
final ProgramExtensionTemplate temp = this.templateMap.get(key);
return new ProgramNode(program, temp, args);
}
/**
* Find a function with the specified name.
*
* @param name
* The name of the function.
* @return The function opcode.
*/
public ProgramExtensionTemplate findFunction(final String name) {
for (final ProgramExtensionTemplate opcode : this.opcodes) {
// only consider functions
if (opcode.getNodeType() == NodeType.Function) {
if (opcode.getName().equals(name)) {
return opcode;
}
}
}
return null;
}
/**
* Find all opcodes that match the search criteria.
*
* @param types
* The return types to consider.
* @param context
* The program context.
* @param includeTerminal
* True, to include the terminals.
* @param includeFunction
* True, to include the functions.
* @return The opcodes found.
*/
public List findOpcodes(
final List types, final EncogProgramContext context,
final boolean includeTerminal, final boolean includeFunction) {
final List result = new ArrayList();
for (final ProgramExtensionTemplate temp : this.opcodes) {
for (final ValueType rtn : types) {
// it is a possible return type, but given our variables, is it
// possible
if (temp.isPossibleReturnType(context, rtn)) {
if (temp.getChildNodeCount() == 0 && includeTerminal) {
result.add(temp);
} else if (includeFunction) {
result.add(temp);
}
}
}
}
return result;
}
/**
* This method is used when parsing an expression. Consider x≥2. The parser
* first sees the > symbol. But it must also consider the =. So we first
* look for a 2-char operator, in this case there is one.
*
* @param ch1
* The first character of the potential operator.
* @param ch2
* The second character of the potential operator. Zero if none.
* @return The expression template for the operator found.
*/
public ProgramExtensionTemplate findOperator(final char ch1, final char ch2) {
ProgramExtensionTemplate result = null;
// if ch2==0 then we are only looking for a single char operator.
// this is rare, but supported.
if (ch2 == 0) {
return findOperatorExact("" + ch1);
}
// first, see if we can match an operator with both ch1 and ch2
result = findOperatorExact("" + ch1 + ch2);
if (result == null) {
// okay no 2-char operators matched, so see if we can find a single
// char
result = findOperatorExact("" + ch1);
}
// return the operator if we have one.
return result;
}
/**
* Find an exact match on opcode.
*
* @param str
* The string to match.
* @return The opcode found.
*/
private ProgramExtensionTemplate findOperatorExact(final String str) {
for (final ProgramExtensionTemplate opcode : this.opcodes) {
// only consider non-unary operators
if (opcode.getNodeType()==NodeType.OperatorLeft || opcode.getNodeType()==NodeType.OperatorRight) {
if (opcode.getName().equals(str)) {
return opcode;
}
}
}
return null;
}
/**
* Get the specified opcode.
*
* @param theOpCode
* The opcode index.
* @return The opcode.
*/
public ProgramExtensionTemplate getOpCode(final int theOpCode) {
return this.opcodes.get(theOpCode);
}
/**
* @return The opcode list.
*/
public List getOpCodes() {
return this.opcodes;
}
/**
* @return the templateMap
*/
public Map getTemplateMap() {
return this.templateMap;
}
/**
* Determine if an opcode is in the function factory.
*
* @param name
* The name of the opcode.
* @param l
* The argument count for the opcode.
* @return True if the opcode exists.
*/
public boolean isDefined(final String name, final int l) {
final String key = EncogOpcodeRegistry.createKey(name, l);
return this.templateMap.containsKey(key);
}
/**
* @return The number of opcodes.
*/
public int size() {
return this.opcodes.size();
}
}
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