simple-squiggle

pow.js (5880B)

---

 "use strict";
 
 Object.defineProperty(exports, "__esModule", {
   value: true
 });
 exports.createPow = void 0;
 
 var _factory = require("../../utils/factory.js");
 
 var _number = require("../../utils/number.js");
 
 var _array = require("../../utils/array.js");
 
 var _index = require("../../plain/number/index.js");
 
 var name = 'pow';
 var dependencies = ['typed', 'config', 'identity', 'multiply', 'matrix', 'fraction', 'number', 'Complex'];
 var createPow = /* #__PURE__ */(0, _factory.factory)(name, dependencies, function (_ref) {
   var typed = _ref.typed,
       config = _ref.config,
       identity = _ref.identity,
       multiply = _ref.multiply,
       matrix = _ref.matrix,
       number = _ref.number,
       fraction = _ref.fraction,
       Complex = _ref.Complex;
 
   /**
    * Calculates the power of x to y, `x ^ y`.
    * Matrix exponentiation is supported for square matrices `x`, and positive
    * integer exponents `y`.
    *
    * For cubic roots of negative numbers, the function returns the principal
    * root by default. In order to let the function return the real root,
    * math.js can be configured with `math.config({predictable: true})`.
    * To retrieve all cubic roots of a value, use `math.cbrt(x, true)`.
    *
    * Syntax:
    *
    *    math.pow(x, y)
    *
    * Examples:
    *
    *    math.pow(2, 3)               // returns number 8
    *
    *    const a = math.complex(2, 3)
    *    math.pow(a, 2)                // returns Complex -5 + 12i
    *
    *    const b = [[1, 2], [4, 3]]
    *    math.pow(b, 2)               // returns Array [[9, 8], [16, 17]]
    *
    * See also:
    *
    *    multiply, sqrt, cbrt, nthRoot
    *
    * @param  {number | BigNumber | Complex | Unit | Array | Matrix} x  The base
    * @param  {number | BigNumber | Complex} y                          The exponent
    * @return {number | BigNumber | Complex | Array | Matrix} The value of `x` to the power `y`
    */
   return typed(name, {
     'number, number': _pow,
     'Complex, Complex': function ComplexComplex(x, y) {
       return x.pow(y);
     },
     'BigNumber, BigNumber': function BigNumberBigNumber(x, y) {
       if (y.isInteger() || x >= 0 || config.predictable) {
         return x.pow(y);
       } else {
         return new Complex(x.toNumber(), 0).pow(y.toNumber(), 0);
       }
     },
     'Fraction, Fraction': function FractionFraction(x, y) {
       var result = x.pow(y);
 
       if (result != null) {
         return result;
       }
 
       if (config.predictable) {
         throw new Error('Result of pow is non-rational and cannot be expressed as a fraction');
       } else {
         return _pow(x.valueOf(), y.valueOf());
       }
     },
     'Array, number': _powArray,
     'Array, BigNumber': function ArrayBigNumber(x, y) {
       return _powArray(x, y.toNumber());
     },
     'Matrix, number': _powMatrix,
     'Matrix, BigNumber': function MatrixBigNumber(x, y) {
       return _powMatrix(x, y.toNumber());
     },
     'Unit, number | BigNumber': function UnitNumberBigNumber(x, y) {
       return x.pow(y);
     }
   });
   /**
    * Calculates the power of x to y, x^y, for two numbers.
    * @param {number} x
    * @param {number} y
    * @return {number | Complex} res
    * @private
    */
 
   function _pow(x, y) {
     // Alternatively could define a 'realmode' config option or something, but
     // 'predictable' will work for now
     if (config.predictable && !(0, _number.isInteger)(y) && x < 0) {
       // Check to see if y can be represented as a fraction
       try {
         var yFrac = fraction(y);
         var yNum = number(yFrac);
 
         if (y === yNum || Math.abs((y - yNum) / y) < 1e-14) {
           if (yFrac.d % 2 === 1) {
             return (yFrac.n % 2 === 0 ? 1 : -1) * Math.pow(-x, y);
           }
         }
       } catch (ex) {// fraction() throws an error if y is Infinity, etc.
       } // Unable to express y as a fraction, so continue on
 
     } // **for predictable mode** x^Infinity === NaN if x < -1
     // N.B. this behavour is different from `Math.pow` which gives
     // (-2)^Infinity === Infinity
 
 
     if (config.predictable && (x < -1 && y === Infinity || x > -1 && x < 0 && y === -Infinity)) {
       return NaN;
     }
 
     if ((0, _number.isInteger)(y) || x >= 0 || config.predictable) {
       return (0, _index.powNumber)(x, y);
     } else {
       // TODO: the following infinity checks are duplicated from powNumber. Deduplicate this somehow
       // x^Infinity === 0 if -1 < x < 1
       // A real number 0 is returned instead of complex(0)
       if (x * x < 1 && y === Infinity || x * x > 1 && y === -Infinity) {
         return 0;
       }
 
       return new Complex(x, 0).pow(y, 0);
     }
   }
   /**
    * Calculate the power of a 2d array
    * @param {Array} x     must be a 2 dimensional, square matrix
    * @param {number} y    a positive, integer value
    * @returns {Array}
    * @private
    */
 
 
   function _powArray(x, y) {
     if (!(0, _number.isInteger)(y) || y < 0) {
       throw new TypeError('For A^b, b must be a positive integer (value is ' + y + ')');
     } // verify that A is a 2 dimensional square matrix
 
 
     var s = (0, _array.arraySize)(x);
 
     if (s.length !== 2) {
       throw new Error('For A^b, A must be 2 dimensional (A has ' + s.length + ' dimensions)');
     }
 
     if (s[0] !== s[1]) {
       throw new Error('For A^b, A must be square (size is ' + s[0] + 'x' + s[1] + ')');
     }
 
     var res = identity(s[0]).valueOf();
     var px = x;
 
     while (y >= 1) {
       if ((y & 1) === 1) {
         res = multiply(px, res);
       }
 
       y >>= 1;
       px = multiply(px, px);
     }
 
     return res;
   }
   /**
    * Calculate the power of a 2d matrix
    * @param {Matrix} x     must be a 2 dimensional, square matrix
    * @param {number} y    a positive, integer value
    * @returns {Matrix}
    * @private
    */
 
 
   function _powMatrix(x, y) {
     return matrix(_powArray(x.valueOf(), y));
   }
 });
 exports.createPow = createPow;