/*
* Redberry: symbolic tensor computations.
*
* Copyright (c) 2010-2014:
* Stanislav Poslavsky <stvlpos@mail.ru>
* Bolotin Dmitriy <bolotin.dmitriy@gmail.com>
*
* This file is part of Redberry.
*
* Redberry is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Redberry is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Redberry. If not, see <http://www.gnu.org/licenses/>.
*/
package cc.redberry.core.parser;
import cc.redberry.core.context.OutputFormat;
import cc.redberry.core.indices.Indices;
import cc.redberry.core.indices.IndicesBuilder;
import cc.redberry.core.indices.IndicesFactory;
import cc.redberry.core.tensor.Tensor;
import cc.redberry.core.tensor.Tensors;
import java.util.Arrays;
/**
* Abstract syntax tree. The implementation is a simple linked tree.
*
* @author Dmitry Bolotin
* @author Stanislav Poslavsky
* @since 1.0
*/
public class ParseToken {
/**
* Node type.
*/
public final TokenType tokenType;
/**
* Child nodes.
*/
public final ParseToken[] content;
/**
* Parent node.
*/
public ParseToken parent;
/**
* @param tokenType node type
* @param content child nodes
*/
public ParseToken(TokenType tokenType, ParseToken... content) {
this.tokenType = tokenType;
this.content = content;
for (ParseToken node : content)
node.setParent(this);
}
private void setParent(ParseToken parent) {
this.parent = parent;
}
/**
* Returns {@link Indices} of the corresponding mathematical expression.
*
* @return {@link Indices} of the corresponding mathematical expression
*/
public Indices getIndices() {
switch (tokenType) {
case Product:
IndicesBuilder builder = new IndicesBuilder();
for (ParseToken node : content)
builder.append(node.getIndices());
return builder.getIndices();
case Sum:
return IndicesFactory.create(content[0].getIndices());
case Power:
return IndicesFactory.EMPTY_INDICES;
}
throw new ParserException("Unknown tensor type: " + tokenType);
}
@Override
public String toString() {
StringBuilder builder = new StringBuilder();
builder.append(tokenType).append("[");
for (ParseToken node : content)
builder.append(node).append(", ");
builder.deleteCharAt(builder.length() - 1).deleteCharAt(builder.length() - 1).append("]");
return builder.toString();
}
public String toString(OutputFormat mode) {
StringBuilder sb = new StringBuilder();
switch (tokenType) {
case Product:
char operatorChar = mode == OutputFormat.LaTeX ? ' ' : '*';
for (int i = 0; ; ++i) {
sb.append(content[i].toString(mode));
if (i == content.length - 1)
return sb.toString();
sb.append(operatorChar);
}
//throw new RuntimeException();
case Sum:
sb.append("(");
String temp;
for (int i = 0; ; ++i) {
temp = content[i].toString(mode);
if ((temp.charAt(0) == '-' || temp.charAt(0) == '+') && sb.length() != 0)
sb.deleteCharAt(sb.length() - 1);
sb.append(content[i].toString(mode));
if (i == content.length - 1)
return sb.append(")").toString();
sb.append('+');
}
//throw new RuntimeException();
}
throw new RuntimeException("Unsupported token type.");
}
protected Tensor[] contentToTensors() {
Tensor[] tensors = new Tensor[content.length];
for (int i = 0; i < content.length; ++i)
tensors[i] = content[i].toTensor();
return tensors;
}
/**
* Converts this AST to tensor.
*
* @return resulting tensor
*/
public Tensor toTensor() {
switch (tokenType) {
case Sum:
return Tensors.sum(contentToTensors());
case Power:
assert content.length == 2;
return Tensors.pow(content[0].toTensor(), content[1].toTensor());
case Product:
return Tensors.multiplyAndRenameConflictingDummies(contentToTensors());
}
throw new ParserException("Unknown tensor type: " + tokenType);
}
@Override
public boolean equals(Object obj) {
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
final ParseToken other = (ParseToken) obj;
if (this.tokenType != other.tokenType)
return false;
return Arrays.deepEquals(this.content, other.content);
}
}