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

Math.js is an extensive math library for JavaScript and Node.js. It features a flexible expression parser with support for symbolic computation, comes with a large set of built-in functions and constants, and offers an integrated solution to work with dif

import { isConstantNode, isFunctionNode, isOperatorNode, isParenthesisNode, isSymbolNode } from '../../../utils/is.js';
import { factory } from '../../../utils/factory.js';
var name = 'simplifyCore';
var dependencies = ['equal', 'isZero', 'add', 'subtract', 'multiply', 'divide', 'pow', 'ConstantNode', 'OperatorNode', 'FunctionNode', 'ParenthesisNode'];
export var createSimplifyCore = /* #__PURE__ */factory(name, dependencies, _ref => {
  var {
    equal,
    isZero,
    add,
    subtract,
    multiply,
    divide,
    pow,
    ConstantNode,
    OperatorNode,
    FunctionNode,
    ParenthesisNode
  } = _ref;
  var node0 = new ConstantNode(0);
  var node1 = new ConstantNode(1);
  /**
   * simplifyCore() performs single pass simplification suitable for
   * applications requiring ultimate performance. In contrast, simplify()
   * extends simplifyCore() with additional passes to provide deeper
   * simplification.
   *
   * Syntax:
   *
   *     simplify.simplifyCore(expr)
   *
   * Examples:
   *
   *     const f = math.parse('2 * 1 * x ^ (2 - 1)')
   *     math.simplify.simpifyCore(f)                          // Node {2 * x}
   *     math.simplify('2 * 1 * x ^ (2 - 1)', [math.simplify.simpifyCore]) // Node {2 * x}
   *
   * See also:
   *
   *     derivative
   *
   * @param {Node} node
   *     The expression to be simplified
   */

  function simplifyCore(node) {
    if (isOperatorNode(node) && node.isUnary()) {
      var a0 = simplifyCore(node.args[0]);

      if (node.op === '+') {
        // unary plus
        return a0;
      }

      if (node.op === '-') {
        // unary minus
        if (isOperatorNode(a0)) {
          if (a0.isUnary() && a0.op === '-') {
            return a0.args[0];
          } else if (a0.isBinary() && a0.fn === 'subtract') {
            return new OperatorNode('-', 'subtract', [a0.args[1], a0.args[0]]);
          }
        }

        return new OperatorNode(node.op, node.fn, [a0]);
      }
    } else if (isOperatorNode(node) && node.isBinary()) {
      var _a = simplifyCore(node.args[0]);

      var a1 = simplifyCore(node.args[1]);

      if (node.op === '+') {
        if (isConstantNode(_a)) {
          if (isZero(_a.value)) {
            return a1;
          } else if (isConstantNode(a1)) {
            return new ConstantNode(add(_a.value, a1.value));
          }
        }

        if (isConstantNode(a1) && isZero(a1.value)) {
          return _a;
        }

        if (isOperatorNode(a1) && a1.isUnary() && a1.op === '-') {
          return new OperatorNode('-', 'subtract', [_a, a1.args[0]]);
        }

        return new OperatorNode(node.op, node.fn, a1 ? [_a, a1] : [_a]);
      } else if (node.op === '-') {
        if (isConstantNode(_a) && a1) {
          if (isConstantNode(a1)) {
            return new ConstantNode(subtract(_a.value, a1.value));
          } else if (isZero(_a.value)) {
            return new OperatorNode('-', 'unaryMinus', [a1]);
          }
        } // if (node.fn === "subtract" && node.args.length === 2) {


        if (node.fn === 'subtract') {
          if (isConstantNode(a1) && isZero(a1.value)) {
            return _a;
          }

          if (isOperatorNode(a1) && a1.isUnary() && a1.op === '-') {
            return simplifyCore(new OperatorNode('+', 'add', [_a, a1.args[0]]));
          }

          return new OperatorNode(node.op, node.fn, [_a, a1]);
        }
      } else if (node.op === '*') {
        if (isConstantNode(_a)) {
          if (isZero(_a.value)) {
            return node0;
          } else if (equal(_a.value, 1)) {
            return a1;
          } else if (isConstantNode(a1)) {
            return new ConstantNode(multiply(_a.value, a1.value));
          }
        }

        if (isConstantNode(a1)) {
          if (isZero(a1.value)) {
            return node0;
          } else if (equal(a1.value, 1)) {
            return _a;
          } else if (isOperatorNode(_a) && _a.isBinary() && _a.op === node.op) {
            var a00 = _a.args[0];

            if (isConstantNode(a00)) {
              var a00a1 = new ConstantNode(multiply(a00.value, a1.value));
              return new OperatorNode(node.op, node.fn, [a00a1, _a.args[1]], node.implicit); // constants on left
            }
          }

          return new OperatorNode(node.op, node.fn, [a1, _a], node.implicit); // constants on left
        }

        return new OperatorNode(node.op, node.fn, [_a, a1], node.implicit);
      } else if (node.op === '/') {
        if (isConstantNode(_a)) {
          if (isZero(_a.value)) {
            return node0;
          } else if (isConstantNode(a1) && (equal(a1.value, 1) || equal(a1.value, 2) || equal(a1.value, 4))) {
            return new ConstantNode(divide(_a.value, a1.value));
          }
        }

        return new OperatorNode(node.op, node.fn, [_a, a1]);
      } else if (node.op === '^') {
        if (isConstantNode(a1)) {
          if (isZero(a1.value)) {
            return node1;
          } else if (equal(a1.value, 1)) {
            return _a;
          } else {
            if (isConstantNode(_a)) {
              // fold constant
              return new ConstantNode(pow(_a.value, a1.value));
            } else if (isOperatorNode(_a) && _a.isBinary() && _a.op === '^') {
              var a01 = _a.args[1];

              if (isConstantNode(a01)) {
                return new OperatorNode(node.op, node.fn, [_a.args[0], new ConstantNode(multiply(a01.value, a1.value))]);
              }
            }
          }
        }

        return new OperatorNode(node.op, node.fn, [_a, a1]);
      }
    } else if (isParenthesisNode(node)) {
      var c = simplifyCore(node.content);

      if (isParenthesisNode(c) || isSymbolNode(c) || isConstantNode(c)) {
        return c;
      }

      return new ParenthesisNode(c);
    } else if (isFunctionNode(node)) {
      var args = node.args.map(simplifyCore).map(function (arg) {
        return isParenthesisNode(arg) ? arg.content : arg;
      });
      return new FunctionNode(simplifyCore(node.fn), args);
    } else {// cannot simplify
    }

    return node;
  }

  return simplifyCore;
});