simple-squiggle

A restricted subset of Squiggle
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log1p.js (2534B)

      1 import { factory } from '../../utils/factory.js';
      2 import { deepMap } from '../../utils/collection.js';
      3 import { log1p as _log1p } from '../../utils/number.js';
      4 var name = 'log1p';
      5 var dependencies = ['typed', 'config', 'divideScalar', 'log', 'Complex'];
      6 export var createLog1p = /* #__PURE__ */factory(name, dependencies, _ref => {
      7   var {
      8     typed,
      9     config,
     10     divideScalar,
     11     log,
     12     Complex
     13   } = _ref;
     14 
     15   /**
     16    * Calculate the logarithm of a `value+1`.
     17    *
     18    * For matrices, the function is evaluated element wise.
     19    *
     20    * Syntax:
     21    *
     22    *    math.log1p(x)
     23    *    math.log1p(x, base)
     24    *
     25    * Examples:
     26    *
     27    *    math.log1p(2.5)                 // returns 1.252762968495368
     28    *    math.exp(math.log1p(1.4))       // returns 2.4
     29    *
     30    *    math.pow(10, 4)                 // returns 10000
     31    *    math.log1p(9999, 10)            // returns 4
     32    *    math.log1p(9999) / math.log(10) // returns 4
     33    *
     34    * See also:
     35    *
     36    *    exp, log, log2, log10
     37    *
     38    * @param {number | BigNumber | Complex | Array | Matrix} x
     39    *            Value for which to calculate the logarithm of `x+1`.
     40    * @param {number | BigNumber | Complex} [base=e]
     41    *            Optional base for the logarithm. If not provided, the natural
     42    *            logarithm of `x+1` is calculated.
     43    * @return {number | BigNumber | Complex | Array | Matrix}
     44    *            Returns the logarithm of `x+1`
     45    */
     46   return typed(name, {
     47     number: function number(x) {
     48       if (x >= -1 || config.predictable) {
     49         return _log1p(x);
     50       } else {
     51         // negative value -> complex value computation
     52         return _log1pComplex(new Complex(x, 0));
     53       }
     54     },
     55     Complex: _log1pComplex,
     56     BigNumber: function BigNumber(x) {
     57       var y = x.plus(1);
     58 
     59       if (!y.isNegative() || config.predictable) {
     60         return y.ln();
     61       } else {
     62         // downgrade to number, return Complex valued result
     63         return _log1pComplex(new Complex(x.toNumber(), 0));
     64       }
     65     },
     66     'Array | Matrix': function ArrayMatrix(x) {
     67       return deepMap(x, this);
     68     },
     69     'any, any': function anyAny(x, base) {
     70       // calculate logarithm for a specified base, log1p(x, base)
     71       return divideScalar(this(x), log(base));
     72     }
     73   });
     74   /**
     75    * Calculate the natural logarithm of a complex number + 1
     76    * @param {Complex} x
     77    * @returns {Complex}
     78    * @private
     79    */
     80 
     81   function _log1pComplex(x) {
     82     var xRe1p = x.re + 1;
     83     return new Complex(Math.log(Math.sqrt(xRe1p * xRe1p + x.im * x.im)), Math.atan2(x.im, xRe1p));
     84   }
     85 });