mathjs/lib/esm/function/algebra/simplify/simplifyConstant.js

// TODO this could be improved by simplifying seperated constants under associative and commutative operators
import { isFraction, isNode, isOperatorNode } from '../../../utils/is.js';
import { factory } from '../../../utils/factory.js';
import { createUtil } from './util.js';
import { noBignumber, noFraction } from '../../../utils/noop.js';
var name = 'simplifyConstant';
var dependencies = ['typed', 'config', 'mathWithTransform', '?fraction', '?bignumber', 'ConstantNode', 'OperatorNode', 'FunctionNode', 'SymbolNode'];
export var createSimplifyConstant = /* #__PURE__ */factory(name, dependencies, (_ref) => {
  var {
    typed,
    config,
    mathWithTransform,
    fraction,
    bignumber,
    ConstantNode,
    OperatorNode,
    FunctionNode,
    SymbolNode
  } = _ref;
  var {
    isCommutative,
    isAssociative,
    allChildren,
    createMakeNodeFunction
  } = createUtil({
    FunctionNode,
    OperatorNode,
    SymbolNode
  });

  function simplifyConstant(expr, options) {
    var res = foldFraction(expr, options);
    return isNode(res) ? res : _toNode(res);
  }

  function _eval(fnname, args, options) {
    try {
      return _toNumber(mathWithTransform[fnname].apply(null, args), options);
    } catch (ignore) {
      // sometimes the implicit type conversion causes the evaluation to fail, so we'll try again after removing Fractions
      args = args.map(function (x) {
        if (isFraction(x)) {
          return x.valueOf();
        }

        return x;
      });
      return _toNumber(mathWithTransform[fnname].apply(null, args), options);
    }
  }

  var _toNode = typed({
    Fraction: _fractionToNode,
    number: function number(n) {
      if (n < 0) {
        return unaryMinusNode(new ConstantNode(-n));
      }

      return new ConstantNode(n);
    },
    BigNumber: function BigNumber(n) {
      if (n < 0) {
        return unaryMinusNode(new ConstantNode(-n));
      }

      return new ConstantNode(n); // old parameters: (n.toString(), 'number')
    },
    Complex: function Complex(s) {
      throw new Error('Cannot convert Complex number to Node');
    }
  }); // convert a number to a fraction only if it can be expressed exactly,
  // and when both numerator and denominator are small enough


  function _exactFraction(n, options) {
    var exactFractions = options && options.exactFractions !== false;

    if (exactFractions && isFinite(n) && fraction) {
      var f = fraction(n);
      var fractionsLimit = options && typeof options.fractionsLimit === 'number' ? options.fractionsLimit : Infinity; // no limit by default

      if (f.valueOf() === n && f.n < fractionsLimit && f.d < fractionsLimit) {
        return f;
      }
    }

    return n;
  } // Convert numbers to a preferred number type in preference order: Fraction, number, Complex
  // BigNumbers are left alone


  var _toNumber = typed({
    'string, Object': function stringObject(s, options) {
      if (config.number === 'BigNumber') {
        if (bignumber === undefined) {
          noBignumber();
        }

        return bignumber(s);
      } else if (config.number === 'Fraction') {
        if (fraction === undefined) {
          noFraction();
        }

        return fraction(s);
      } else {
        var n = parseFloat(s);
        return _exactFraction(n, options);
      }
    },
    'Fraction, Object': function FractionObject(s, options) {
      return s;
    },
    // we don't need options here
    'BigNumber, Object': function BigNumberObject(s, options) {
      return s;
    },
    // we don't need options here
    'number, Object': function numberObject(s, options) {
      return _exactFraction(s, options);
    },
    'Complex, Object': function ComplexObject(s, options) {
      if (s.im !== 0) {
        return s;
      }

      return _exactFraction(s.re, options);
    }
  });

  function unaryMinusNode(n) {
    return new OperatorNode('-', 'unaryMinus', [n]);
  }

  function _fractionToNode(f) {
    var n;
    var vn = f.s * f.n;

    if (vn < 0) {
      n = new OperatorNode('-', 'unaryMinus', [new ConstantNode(-vn)]);
    } else {
      n = new ConstantNode(vn);
    }

    if (f.d === 1) {
      return n;
    }

    return new OperatorNode('/', 'divide', [n, new ConstantNode(f.d)]);
  }
  /*
   * Create a binary tree from a list of Fractions and Nodes.
   * Tries to fold Fractions by evaluating them until the first Node in the list is hit, so
   * `args` should be sorted to have the Fractions at the start (if the operator is commutative).
   * @param args - list of Fractions and Nodes
   * @param fn - evaluator for the binary operation evaluator that accepts two Fractions
   * @param makeNode - creates a binary OperatorNode/FunctionNode from a list of child Nodes
   * if args.length is 1, returns args[0]
   * @return - Either a Node representing a binary expression or Fraction
   */


  function foldOp(fn, args, makeNode, options) {
    return args.reduce(function (a, b) {
      if (!isNode(a) && !isNode(b)) {
        try {
          return _eval(fn, [a, b], options);
        } catch (ignoreandcontinue) {}

        a = _toNode(a);
        b = _toNode(b);
      } else if (!isNode(a)) {
        a = _toNode(a);
      } else if (!isNode(b)) {
        b = _toNode(b);
      }

      return makeNode([a, b]);
    });
  } // destroys the original node and returns a folded one


  function foldFraction(node, options) {
    switch (node.type) {
      case 'SymbolNode':
        return node;

      case 'ConstantNode':
        if (typeof node.value === 'number' || !isNaN(node.value)) {
          return _toNumber(node.value, options);
        }

        return node;

      case 'FunctionNode':
        if (mathWithTransform[node.name] && mathWithTransform[node.name].rawArgs) {
          return node;
        }

        {
          // Process operators as OperatorNode
          var operatorFunctions = ['add', 'multiply'];

          if (operatorFunctions.indexOf(node.name) === -1) {
            var args = node.args.map(arg => foldFraction(arg, options)); // If all args are numbers

            if (!args.some(isNode)) {
              try {
                return _eval(node.name, args, options);
              } catch (ignoreandcontine) {}
            } // Convert all args to nodes and construct a symbolic function call


            args = args.map(function (arg) {
              return isNode(arg) ? arg : _toNode(arg);
            });
            return new FunctionNode(node.name, args);
          } else {// treat as operator
          }
        }

      /* falls through */

      case 'OperatorNode':
        {
          var fn = node.fn.toString();

          var _args;

          var res;
          var makeNode = createMakeNodeFunction(node);

          if (isOperatorNode(node) && node.isUnary()) {
            _args = [foldFraction(node.args[0], options)];

            if (!isNode(_args[0])) {
              res = _eval(fn, _args, options);
            } else {
              res = makeNode(_args);
            }
          } else if (isAssociative(node)) {
            _args = allChildren(node);
            _args = _args.map(arg => foldFraction(arg, options));

            if (isCommutative(fn)) {
              // commutative binary operator
              var consts = [];
              var vars = [];

              for (var i = 0; i < _args.length; i++) {
                if (!isNode(_args[i])) {
                  consts.push(_args[i]);
                } else {
                  vars.push(_args[i]);
                }
              }

              if (consts.length > 1) {
                res = foldOp(fn, consts, makeNode, options);
                vars.unshift(res);
                res = foldOp(fn, vars, makeNode, options);
              } else {
                // we won't change the children order since it's not neccessary
                res = foldOp(fn, _args, makeNode, options);
              }
            } else {
              // non-commutative binary operator
              res = foldOp(fn, _args, makeNode, options);
            }
          } else {
            // non-associative binary operator
            _args = node.args.map(arg => foldFraction(arg, options));
            res = foldOp(fn, _args, makeNode, options);
          }

          return res;
        }

      case 'ParenthesisNode':
        // remove the uneccessary parenthesis
        return foldFraction(node.content, options);

      case 'AccessorNode':
      /* falls through */

      case 'ArrayNode':
      /* falls through */

      case 'AssignmentNode':
      /* falls through */

      case 'BlockNode':
      /* falls through */

      case 'FunctionAssignmentNode':
      /* falls through */

      case 'IndexNode':
      /* falls through */

      case 'ObjectNode':
      /* falls through */

      case 'RangeNode':
      /* falls through */

      case 'ConditionalNode':
      /* falls through */

      default:
        throw new Error("Unimplemented node type in simplifyConstant: ".concat(node.type));
    }
  }

  return simplifyConstant;
});