示例#1
0
文件: Sum.java 项目: vikasdhar/symja
  @Override
  public IExpr evaluate(final IAST ast) {
    Validate.checkRange(ast, 3);

    if (ast.size() == 3 && ast.get(2).isList() && ((IAST) ast.get(2)).size() == 4) {
      IAST list = (IAST) ast.get(2);
      if (ast.get(1).isPlus()) {
        return ((IAST) ast.get(1)).map(Functors.replace1st(F.Sum(F.Null, ast.get(2))));
      }
      if (list.get(1).isSymbol() && list.get(2).isInteger() && list.get(3).isSymbol()) {
        final ISymbol var = (ISymbol) list.get(1);
        final IInteger from = (IInteger) list.get(2);
        final ISymbol to = (ISymbol) list.get(3);
        if (ast.get(1).isFree(var, true) && ast.get(1).isFree(to, true)) {
          if (from.equals(F.C1)) {
            return F.Times(to, ast.get(1));
          }
          if (from.equals(F.C0)) {
            return F.Times(Plus(to, C1), ast.get(1));
          }
        } else {
          if (ast.get(1).isTimes()) {
            // Sum[ Times[a,b,c,...], {var, from, to} ]
            IAST filterCollector = F.Times();
            IAST restCollector = F.Times();
            ((IAST) ast.get(1))
                .filter(
                    filterCollector,
                    restCollector,
                    new Predicate<IExpr>() {
                      @Override
                      public boolean apply(IExpr input) {
                        return input.isFree(var, true) && input.isFree(to, true);
                      }
                    });
            if (filterCollector.size() > 1) {
              if (restCollector.size() == 2) {
                filterCollector.add(F.Sum(restCollector.get(1), ast.get(2)));
              } else {
                filterCollector.add(F.Sum(restCollector, ast.get(2)));
              }
              return filterCollector;
            }
          }

          if (from.equals(F.C0)) {
            IExpr repl =
                ast.get(1).replaceAll(F.List(F.Rule(var, F.Slot(F.C1)), F.Rule(to, F.Slot(F.C2))));
            if (repl != null) {
              IExpr temp = MAP_0_N.get(repl);
              if (temp != null) {
                return temp.replaceAll(F.Rule(F.Slot(F.C1), to));
              }
            }
          }
        }
        if (from.isPositive()) {
          return F.Subtract(
              F.Sum(ast.get(1), F.List(var, C0, to)),
              F.Sum(ast.get(1), F.List(var, C0, from.minus(F.C1))));
        }
      }
    }
    IAST resultList = Plus();
    IExpr temp = evaluateTable(ast, resultList, C0);
    if (temp.equals(resultList)) {
      return null;
    }
    return temp;
  }
示例#2
0
 @Override
 public void setUp(final ISymbol symbol) throws SyntaxError {
   symbol.setAttributes(ISymbol.LISTABLE);
   REPLACE_RULES = Functors.rules(REPLACE_STRINGS);
   super.setUp(symbol);
 }