How to use

isAllowSameVariance

method

in

cc.redberry.core.parser.Parser

/**
 * Returns whether repeated indices of the same variance are allowed to be parsed
 *
 * @return whether repeated indices of the same variance are allowed to be parsed
 */
public boolean getParserAllowsSameVariance() {
  return parseManager.getParser().isAllowSameVariance();
}

@Override
public final ParseTokenSimpleTensor parseToken(String expression, Parser parser) {
  expression = expression.replaceAll("\\{[\\s]*\\}", "");
  int indicesBegin = expression.indexOf('_'), i = expression.indexOf('^');
  if (indicesBegin < 0 && i >= 0)
    indicesBegin = i;
  if (indicesBegin >= 0 && i >= 0)
    indicesBegin = Math.min(indicesBegin, i);
  if (indicesBegin < 0)
    indicesBegin = expression.length();
  String name = expression.substring(0, indicesBegin);
  if (name.isEmpty())
    throw new ParserException("Simple tensor with empty name.");
  SimpleIndices indices;
  if (parser.isAllowSameVariance())
    indices = ParserIndices.parseSimpleIgnoringVariance(expression.substring(indicesBegin));
  else
    indices = ParserIndices.parseSimple(expression.substring(indicesBegin));
  return new ParseTokenSimpleTensor(indices, name);
}

@Override
public ParseToken parseToken(String expression, Parser parser) {
  ParseToken node = super.parseToken(expression, parser);
  if (node == null || !parser.isAllowSameVariance())
    return node;
  TIntHashSet indices = new TIntHashSet();
  for (ParseToken c : node.content) {
    Indices free = c.getIndices().getFree();
    for (int i = 0; i < free.size(); i++) {
      int ind = free.get(i);
      if (indices.contains(ind))
        revertIndex(c, ind);
      else indices.add(ind);
    }
  }
  return node;
}