# History


## 2016-07-05, version 3.3.0

- Implemented function `isNaN`.
- Function `math.filter` now passes three arguments to the callback function:
  value, index, and array.
- Removed the check on the number of arguments from functions defined in the
  expression parser (see #665).
- Fixed #665: functions `map`, `forEach`, and `filter` now invoke callbacks
  which are a typed-function with the correct number of arguments.


## 2016-04-26, version 3.2.1

- Fixed #651: unable to perform calculations on "Unit-less" units.
- Fixed matrix.subset mutating the replacement matrix when unsqueezing it.


## 2016-04-16, version 3.2.0

- Implemented #644: method `Parser.getAll()` to retrieve all defined variables.
- Upgraded dependencies (decimal.js@5.0.8, fraction.js@3.3.1,
  typed-function@0.10.4).
- Fixed #601: Issue with unnamed typed-functions by upgrading to
  typed-function v0.10.4.
- Fixed #636: More strict `toTex` templates, reckon with number of arguments.
- Fixed #641: Bug in expression parser parsing implicit multiplication with
  wrong precedence in specific cases.
- Fixed #645: Added documentation about `engineering` notation of function
  `math.format`.


## 2016-04-03, version 3.1.4

- Using ES6 Math functions like `Math.sinh`, `Math.cbrt`, `Math.sign`, etc when
  available.
- Fixed #631: unit aliases `weeks`, `months`, and `years` where missing.
- Fixed #632: problem with escaped backslashes at the end of strings.
- Fixed #635: `Node.toString` options where not passed to function arguments.
- Fixed #629: expression parser throws an error when passing a number with
  decimal exponent instead of parsing them as implicit multiplication.
- Fixed #484, #555: inaccuracy of `math.sinh` for values between -1 and 1.
- Fixed #625: Unit `in` (`inch`) not always working due to ambiguity with
  the operator `a in b` (alias of `a to b`).


## 2016-03-24, version 3.1.3

- Fix broken bundle.


## 2016-03-24, version 3.1.2

- Fix broken npm release.


## 2016-03-24, version 3.1.1

- Fixed #621: a bug in parsing implicit multiplications like `(2)(3)+4`.
- Fixed #623: `nthRoot` of zero with a negative root returned `0` instead of
  `Infinity`.
- Throw an error when functions `min`, `max`, `mean`, or `median` are invoked
  with multiple matrices as arguments (see #598).


## 2016-03-19, version 3.1.0

- Hide multiplication operator by default when outputting `toTex` and `toString`
  for implicit multiplications. Implemented and option to output the operator.
- Implemented unit `kip` and alias `kips`. Thanks @hgupta9.
- Added support for prefixes for units `mol` and `mole`. Thanks @stu-blair.
- Restored support for implicit multiplications like `2(3+4)` and `(2+3)(4+5)`.
- Some improvements in the docs.
- Added automatic conversions from `boolean` and `null` to `Fraction`,
  and conversions from `Fraction` to `Complex`.


## 2016-03-04, version 3.0.0

### breaking changes

- More restricted support for implicit multiplication in the expression
  parser: `(...)(...)` is now evaluated as a function invocation,
  and `[...][...]` as a matrix subset.
- Matrix multiplication no longer squeezes scalar outputs to a scalar value,
  but leaves them as they are: a vector or matrix containing a single value.
  See #529.
- Assignments in the expression parser now return the assigned value rather
  than the created or updated object (see #533). Example:

  ```
  A = eye(3)
  A[1,1] = 2   # this assignment now returns 2 instead of A
  ```

- Expression parser now supports objects. This involves a refactoring and
  extension in expression nodes:
  - Implemented new node `ObjectNode`.
  - Refactored `AssignmentNode`, `UpdateNode`, and `IndexNode` are refactored
    into `AccessorNode`, `AssignmentNode`, and `IndexNode` having a different API.
- Upgraded the used BigNumber library `decimal.js` to v5. Replaced the
  trigonometric functions of math.js with those provided in decimal.js v5.
  This can give slightly different behavior qua round-off errors.
- Replaced the internal `Complex.js` class with the `complex.js` library
  created by @infusion.
- Entries in a matrix (typically numbers, BigNumbers, Units, etc) are now
  considered immutable, they are no longer copied when performing operations on
  the entries, improving performance.
- Implemented nearly equal comparison for relational functions (`equal`,
  `larger`, `smaller`, etc.) when using BigNumbers.
- Changed the casing of the configuration options `matrix` (`Array` or `Matrix`)
  and `number` (`number`, `BigNumber`, `Fraction`) such that they now match
  the type returned by `math.typeof`. Wrong casing gives a console warning but
  will still work.
- Changed the default config value for `epsilon` from `1e-14` to `1e-12`,
  see #561.

### non-breaking changes

- Extended function `pow` to return the real root for cubic roots of negative
  numbers. See #525, #482, #567.
- Implemented support for JSON objects in the expression parser and the
  function `math.format`.
- Function `math.fraction` now supports `BigNumber`, and function
  `math.bignumber` now supports `Fraction`.
- Expression parser now allows function and/or variable assignments inside
  accessors and conditionals, like `A[x=2]` or `a > 2 ? b="ok" : b="fail"`.
- Command line interface:
  - Outputs the variable name of assignments.
  - Fixed not rounding BigNumbers to 14 digits like numbers.
  - Fixed non-working autocompletion of user defined variables.
- Reorganized and extended docs, added docs on classes and more. Thanks @hgupta9.
- Added new units `acre`, `hectare`, `torr`, `bar`, `mmHg`, `mmH2O`, `cmH2O`,
  and added new aliases `acres`, `hectares`, `sqfeet`, `sqyard`, `sqmile`,
  `sqmiles`, `mmhg`, `mmh2o`, `cmh2o`. Thanks @hgupta9.
- Fixed a bug in the toString method of an IndexNode.
- Fixed angle units `deg`, `rad`, `grad`, `cycle`, `arcsec`, and `arcmin` not
  being defined as BigNumbers when configuring to use BigNumbers.


## 2016-02-03, version 2.7.0

- Added more unit aliases for time: `secs`, `mins`, `hr`, `hrs`. See #551.
- Added support for doing operations with mixed `Fractions` and `BigNumbers`.
- Fixed #540: `math.intersect()` returning null in some cases. Thanks @void42.
- Fixed #546: Cannot import BigNumber, Fraction, Matrix, Array.
  Thanks @brettjurgens.


## 2016-01-08, version 2.6.0

- Implemented (complex) units `VA` and `VAR`.
- Implemented time units for weeks, months, years, decades, centuries, and 
  millennia. Thanks @owenversteeg.
- Implemented new notation `engineering` in function `math.format`. 
  Thanks @johnmarinelli.
- Fixed #523: In some circumstances, matrix subset returned a scalar instead 
  of the correct subset.
- Fixed #536: A bug in an internal method used for sparse matrices.


## 2015-12-05, version 2.5.0

- Implemented support for numeric types `Fraction` and `BigNumber` in units.
- Implemented new method `toNumeric` for units.
- Implemented new units `arcsec`, `arcsecond`, `arcmin`, `arcminute`. 
  Thanks @devdevdata222.
- Implemented new unit `Herts` (`Hz`). Thanks @SwamWithTurtles.
- Fixed #485: Scoping issue with variables both used globally as well as in a 
  function definition.
- Fixed: Function `number` didn't support `Fraction` as input.


## 2015-11-14, version 2.4.2

- Fixed #502: Issue with `format` in some JavaScript engines.
- Fixed #503: Removed trailing commas and the use of keyword `import` as 
  property, as this gives issues with old JavaScript engines.


## 2015-10-29, version 2.4.1

- Fixed #480: `nthRoot` not working on Internet Explorer (up to IE 11).
- Fixed #490: `nthRoot` returning an error for negative values like 
  `nthRoot(-2, 3)`.
- Fixed #489: an issue with initializing a sparse matrix without data.
  Thanks @Retsam.
- Fixed: #493: function `combinations` did not throw an exception for 
  non-integer values of `k`.
- Fixed: function `import` did not override typed functions when the option
  override was set true.
- Fixed: added functions `math.sparse` and `math.index` to the reference docs, 
  they where missing.
- Fixed: removed memoization from `gamma` and `factorial` functions, this 
  could blow up memory.


## 2015-10-09, version 2.4.0

- Added support in the expression parser for mathematical alphanumeric symbols 
  in the expression parser: unicode range \u{1D400} to \u{1D7FF} excluding 
  invalid code points.
- Extended function `distance` with more signatures. Thanks @kv-kunalvyas.
- Fixed a bug in functions `sin` and `cos`, which gave wrong results for 
  BigNumber integer values around multiples of tau (i.e. `sin(bignumber(7))`).
- Fixed value of unit `stone`. Thanks @Esvandiary for finding the error.


## 2015-09-19, version 2.3.0

- Implemented function `distance`. Thanks @devanp92.
- Implemented support for Fractions in function `lcm`. Thanks @infusion.
- Implemented function `cbrt` for numbers, complex numbers, BigNumbers, Units.
- Implemented function `hypot`.
- Upgraded to fraction.js v3.0.0.
- Fixed #450: issue with non sorted index in sparse matrices.
- Fixed #463, #322: inconsistent handling of implicit multiplication.
- Fixed #444: factorial of infinity not returning infinity.


## 2015-08-30, version 2.2.0

- Units with powers (like `m^2` and `s^-1`) now output with the best prefix.
- Implemented support for units to `abs`, `cube`, `sign`, `sqrt`, `square`.
  Thanks @ericman314.
- Implemented function `catalan` (Combinatorics). Thanks @devanp92.
- Improved the `canDefineProperty` check to return false in case of IE8, which
  has a broken implementation of `defineProperty`. Thanks @golmansax.
- Fixed function `to` not working in case of a simplified unit.
- Fixed #437: an issue with row swapping in `lup`, also affecting `lusolve`.


## 2015-08-12, version 2.1.1

- Fixed wrong values of the physical constants `speedOfLight`, `molarMassC12`,  
  and `magneticFluxQuantum`. Thanks @ericman314 for finding two of them.


## 2015-08-11, version 2.1.0

- Implemented derived units (like `110 km/h in m/s`). Thanks @ericman314.
- Implemented support for electric units. Thanks @ericman314.
- Implemented about 50 physical constants like `speedOfLight`, `gravity`, etc. 
- Implemented function `kldivergence` (Kullback-Leibler divergence). 
  Thanks @saromanov.
- Implemented function `mode`. Thanks @kv-kunalvyas.
- Added support for unicode characters in the expression parser: greek letters
  and latin letters with accents. See #265.
- Internal functions `Unit.parse` and `Complex.parse` now throw an Error 
  instead of returning null when passing invalid input.


## 2015-07-29, version 2.0.1

- Fixed operations with mixed fractions and numbers be converted to numbers
  instead of fractions.


## 2015-07-28, version 2.0.0

- Large internal refactoring:
  - performance improvements.
  - allows to create custom bundles
  - functions are composed using `typed-function` and are extensible
- Implemented support for fractions, powered by the library `fraction.js`.
- Implemented matrix LU decomposition with partial pivoting and a LU based 
  linear equations solver (functions `lup` and `lusolve`). Thanks @rjbaucells.
- Implemented a new configuration option `predictable`, which can be set to
  true in order to ensure predictable function output types.
- Implemented function `intersect`. Thanks @kv-kunalvyas.
- Implemented support for adding `toTex` properties to custom functions.
  Thanks @FSMaxB.
- Implemented support for complex values to `nthRoot`. Thanks @gangachris.
- Implemented util functions `isInteger`, `isNegative`, `isNumeric`, 
  `isPositive`, and `isZero`.

### breaking changes

- String input is now converted to numbers by default for all functions. 
- Adding two strings will no longer concatenate them, but will convert the 
  strings to numbers and add them.
- Function `index` does no longer accept an array `[start, end, step]`, but
  instead accepts an array with arbitrary index values. It also accepts
  a `Range` object as input.
- Function `typeof` no longer returns lower case names, but now returns lower
  case names for primitives (like `number`, `boolean`, `string`), and 
  upper-camel-case for non-primitives (like `Array`, `Complex`, `Function`).
- Function `import` no longer supports a module name as argument. Instead,
  modules can be loaded using require: `math.import(require('module-name'))`.
- Function `import` has a new option `silent` to ignore errors, and throws
  errors on duplicates by default.
- Method `Node.compile()` no longer needs `math` to be passed as argument.
- Reintroduced method `Node.eval([scope])`.
- Function `sum` now returns zero when input is an empty array. Thanks @FSMAxB.
- The size of Arrays is no longer validated. Matrices will validate this on
  creation.


## 2015-07-12, version 1.7.1

- Fixed #397: Inaccuracies in nthRoot for very large values, and wrong results 
  for very small values. (backported from v2)
- Fixed #405: Parser throws error when defining a function in a multiline 
  expression.


## 2015-05-31, version 1.7.0

- Implemented function `quantileSeq` and `partitionSelect`. Thanks @BigFav.
- Implemented functions `stirlingS2`, `bellNumbers`, `composition`, and 
  `multinomial`. Thanks @devanp92.
- Improved the performance of `median` (see #373). Thanks @BigFav.
- Extended the command line interface with a `mode` option to output either
  the expressions result, string representation, or tex representation.
  Thanks @FSMaxB.
- Fixed #309: Function median mutating the input matrix. Thanks @FSMaxB. 
- Fixed `Node.transform` not recursing over replaced parts of the 
  node tree (see #349).
- Fixed #381: issue in docs of `randomInt`.


## 2015-04-22, version 1.6.0

- Improvements in `toTex`. Thanks @FSMaxB.
- Fixed #328: `abs(0 + 0i)` evaluated to `NaN`.
- Fixed not being able to override lazy loaded constants.


## 2015-04-09, version 1.5.2

- Fixed #313: parsed functions did not handle recursive calls correctly.
- Fixed #251: binary prefix and SI prefix incorrectly used for byte. Now 
  following SI standards (`1 KiB == 1024 B`, `1 kB == 1000 B`).
- Performance improvements in parsed functions.


## 2015-04-08, version 1.5.1

- Fixed #316: a bug in rounding values when formatting.
- Fixed #317, #319: a bug in formatting negative values.


## 2015-03-28, version 1.5.0

- Added unit `stone` (6.35 kg).
- Implemented support for sparse matrices. Thanks @rjbaucells.
- Implemented BigNumber support for function `atan2`. Thanks @BigFav.
- Implemented support for custom LaTeX representations. Thanks @FSMaxB.
- Improvements and bug fixes in outputting parentheses in `Node.toString` and
  `Node.toTex` functions. Thanks @FSMaxB.
- Fixed #291: function `format` sometimes returning exponential notation when
  it should return a fixed notation.


## 2015-02-28, version 1.4.0

- Implemented trigonometric functions:
  `acosh`, `acoth`, `acsch`, `asech`, `asinh`, `atanh`, `acot`, `acsc`, `asec`.
  Thanks @BigFav.
- Added BigNumber support for functions: `cot`, `csc`, `sec`, `coth`,
  `csch`, `sech`. Thanks @BigFav.
- Implemented support for serialization and deserialization of math.js data
  types.
- Fixed the calculation of `norm()` and `abs()` for large complex numbers.
  Thanks @rjbaucells.
- Fixed #281: improved formatting complex numbers. Round the real or imaginary
  part to zero when the difference is larger than the configured precision.


## 2015-02-09, version 1.3.0

- Implemented BigNumber implementations of most trigonometric functions: `sin`,
  `cos`, `tan`, `asin`, `acos`, `atan`, `cosh`, `sinh`, `tanh`. Thanks @BigFav.
- Implemented function `trace`. Thanks @pcorey.
- Faster loading of BigNumber configuration with a high precision by lazy
  loading constants like `pi` and `e`.
- Fixed constants `NaN` and `Infinity` not being BigNumber objects when
  BigNumbers are configured.
- Fixed missing parentheses in the `toTex` representation of function
  `permutations`.
- Some minor fixes in the docs. Thanks @KenanY.


## 2014-12-25, version 1.2.0

- Support for bitwise operations `bitAnd`, `bitNot`, `bitOr`, `bitXor`,
  `leftShift`, `rightArithShift`, and `rightLogShift`. Thanks @BigFav.
- Support for boolean operations `and`, `not`, `or`, `xor`. Thanks @BigFav.
- Support for `gamma` function. Thanks @BigFav.
- Converting a unit without value will now result in a unit *with* value,
  i.e. `inch in cm` will return `2.54 cm` instead of `cm`.
- Improved accuracy of `sinh` and complex `cos` and `sin`. Thanks @pavpanchekha.
- Renamed function `select` to `chain`. The old function `select` will remain
  functional until math.js v2.0.
- Upgraded to decimal.js v4.0.1 (BigNumber library).


## 2014-11-22, version 1.1.1

- Fixed Unit divided by Number returning zero.
- Fixed BigNumber downgrading to Number for a negative base in `pow`.
- Fixed some typos in error messaging (thanks @andy0130tw) and docs.


## 2014-11-15, version 1.1.0

- Implemented functions `dot` (dot product), `cross` (cross product), and
  `nthRoot`.
- Officially opened up the API of expression trees:
  - Documented the API.
  - Implemented recursive functions `clone`, `map`, `forEach`, `traverse`,
    `transform`, and `filter` for expression trees.
  - Parameter `index` in the callbacks of `map` and `forEach` are now cloned
    for every callback.
  - Some internal refactoring inside nodes to make the API consistent:
    - Renamed `params` to `args` and vice versa to make things consistent.
    - Renamed `Block.nodes` to `Block.blocks`.
    - `FunctionNode` now has a `name: string` instead of a `symbol: SymbolNode`.
    - Changed constructor of `RangeNode` to
      `new RangeNode(start: Node, end: Node [, step: Node])`.
    - Nodes for a `BlockNode` must now be passed via the constructor instead
      of via a function `add`.
- Fixed `2e` giving a syntax error instead of being parsed as `2 * e`.


## 2014-09-12, version 1.0.1

- Disabled array notation for ranges in a matrix index in the expression parser 
  (it is confusing and redundant there).
- Fixed a regression in the build of function subset not being able to return
  a scalar.
- Fixed some missing docs and broken links in the docs.


## 2014-09-04, version 1.0.0

- Implemented a function `filter(x, test)`.
- Removed `math.distribution` for now, needs some rethinking.
- `math.number` can convert units to numbers (requires a second argument)
- Fixed some precedence issues with the range and conversion operators.
- Fixed an zero-based issue when getting a matrix subset using an index 
  containing a matrix.


## 2014-08-21, version 0.27.0

- Implemented functions `sort(x [, compare])` and `flatten(x)`.
- Implemented support for `null` in all functions.
- Implemented support for "rawArgs" functions in the expression parser. Raw 
  functions are invoked with unevaluated parameters (nodes).
- Expressions in the expression parser can now be spread over multiple lines,
  like '2 +\n3'.
- Changed default value of the option `wrap` of function `math.import` to false.
- Changed the default value for new entries in a resized matrix when to zero. 
  To leave new entries uninitialized, use the new constant `math.uninitialized` 
  as default value.
- Renamed transform property from `__transform__` to `transform`, and documented
  the transform feature.
- Fixed a bug in `math.import` not applying options when passing a module name.
- A returned matrix subset is now only squeezed when the `index` consists of
  scalar values, and no longer for ranges resolving into a single value. 


## 2014-08-03, version 0.26.0

- A new instance of math.js can no longer be created like `math([options])`,
  to prevent side effects from math being a function instead of an object.
  Instead, use the function `math.create([options])` to create a new instance.
- Implemented `BigNumber` support for all constants: `pi`, `tau`, `e`, `phi`,
  `E`, `LN2`, `LN10`, `LOG2E`, `LOG10E`, `PI`, `SQRT1_2`, and `SQRT2`.
- Implemented `BigNumber` support for functions `gcd`, `xgcd`, and `lcm`.
- Fixed function `gxcd` returning an Array when math.js was configured 
  as `{matrix: 'matrix'}`.
- Multi-line expressions now return a `ResultSet` instead of an `Array`.
- Implemented transforms (used right now to transform one-based indices to 
  zero-based for expressions).
- When used inside the expression parser, functions `concat`, `min`, `max`,
  and `mean` expect an one-based dimension number.
- Functions `map` and `forEach` invoke the callback with one-based indices
  when used from within the expression parser.
- When adding or removing dimensions when resizing a matrix, the dimensions
  are added/removed from the inner side (right) instead of outer side (left).
- Improved index out of range errors.
- Fixed function `concat` not accepting a `BigNumber` for parameter `dim`.
- Function `squeeze` now squeezes both inner and outer singleton dimensions.
- Output of getting a matrix subset is not automatically squeezed anymore
  except for scalar output.
- Renamed `FunctionNode` to `FunctionAssignmentNode`, and renamed `ParamsNode`
  to `FunctionNode` for more clarity.
- Fixed broken auto completion in CLI.
- Some minor fixes.


## 2014-07-01, version 0.25.0

- The library now immediately returns a default instance of mathjs, there is
  no need to instantiate math.js in a separate step unless one ones to set 
  configuration options: 
  
        // instead of:
        var mathjs = require('mathjs'),  // load math.js
            math = mathjs();             // create an instance
      
        // just do:
        var math = require('mathjs');
- Implemented support for implicit multiplication, like `math.eval('2a', {a:3})`
  and `math.eval('(2+3)(1-3)')`. This changes behavior of matrix indexes as 
  well: an expression like `[...][...]` is not evaluated as taking a subset of 
  the first matrix, but as an implicit multiplication of two matrices.
- Removed utility function `ifElse`. This function is redundant now the 
  expression parser has a conditional operator `a ? b : c`.
- Fixed a bug with multiplying a number with a temperature,  
  like `math.eval('10 * celsius')`.
- Fixed a bug with symbols having value `undefined` not being evaluated.


## 2014-06-20, version 0.24.1

- Something went wrong with publishing on npm.


## 2014-06-20, version 0.24.0

- Added constant `null`.
- Functions `equal` and `unequal` support `null` and `undefined` now.
- Function `typeof` now recognizes regular expressions as well.
- Objects `Complex`, `Unit`, and `Help` now return their string representation
  when calling `.valueOf()`.
- Changed the default number of significant digits for BigNumbers from 20 to 64.
- Changed the behavior of the conditional operator (a ? b : c) to lazy 
  evaluating.
- Fixed imported, wrapped functions not accepting `null` and `undefined` as
  function arguments.


## 2014-06-10, version 0.23.0

- Renamed some functions (everything now has a logical, camel case name):
  - Renamed functions `edivide`, `emultiply`, and `epow` to `dotDivide`, 
    `dotMultiply`, and `dotPow` respectively. 
  - Renamed functions `smallereq` and `largereq` to `smallerEq` and `largerEq`.
  - Renamed function `unary` to `unaryMinus` and added support for strings.
- `end` is now a reserved keyword which cannot be used as function or symbol
  name in the expression parser, and is not allowed in the scope against which
  an expression is evaluated.
- Implemented function `unaryPlus` and unary plus operator.
- Implemented function `deepEqual` for matrix comparisons. 
- Added constant `phi`, the golden ratio (`phi = 1.618...`).
- Added constant `version`, returning the version number of math.js as string.
- Added unit `drop` (`gtt`).
- Fixed not being able to load math.js using AMD/require.js.
- Changed signature of `math.parse(expr, nodes)` to `math.parse(expr, options)`
  where `options: {nodes: Object.<String, Node>}`
- Removed matrix support from conditional function `ifElse`.
- Removed automatic assignment of expression results to variable `ans`. 
  This functionality can be restored by pre- or postprocessing every evaluation, 
  something like:
  
        function evalWithAns (expr, scope) {
          var ans = math.eval(expr, scope);
          if (scope) {
            scope.ans = ans;
          }
          return ans;
        }


## 2014-05-22, version 0.22.0

- Implemented support to export expressions to LaTeX. Thanks Niels Heisterkamp
  (@nheisterkamp).
- Output of matrix multiplication is now consistently squeezed.
- Added reference documentation in the section /docs/reference.
- Fixed a bug in multiplying units without value with a number (like `5 * cm`).
- Fixed a bug in multiplying two matrices containing vectors (worked fine for 
  arrays).
- Fixed random functions not accepting Matrix as input, and always returning
  a Matrix as output.


## 2014-05-13, version 0.21.1

- Removed `crypto` library from the bundle.
- Deprecated functions `Parser.parse` and `Parser.compile`. Use
  `math.parse` and `math.compile` instead.
- Fixed function `add` not adding strings and matrices element wise.
- Fixed parser not being able to evaluate an exponent followed by a unary minus
  like `2^-3`, and a transpose followed by an index like `[3]'[1]`.


## 2014-04-24, version 0.21.0

- Implemented trigonometric hyperbolic functions `cosh`, `coth`, `csch`,
  `sech`, `sinh`, `tanh`. Thanks Rogelio J. Baucells (@rjbaucells).
- Added property `type` to all expression nodes in an expression tree.
- Fixed functions `log`, `log10`, `pow`, and `sqrt` not supporting complex
  results from BigNumber input (like `sqrt(bignumber(-4))`).


## 2014-04-16, version 0.20.0

- Switched to module `decimal.js` for BigNumber support, instead of
  `bignumber.js`.
- Implemented support for polar coordinates to the `Complex` datatype.
  Thanks Finn Pauls (@finnp).
- Implemented BigNumber support for functions `exp`, `log`, and `log10`.
- Implemented conditional operator `a ? b : c` in expression parser.
- Improved floating point comparison: the functions now check whether values
  are nearly equal, against a configured maximum relative difference `epsilon`.
  Thanks Rogelio J. Baucells (@rjbaucells).
- Implemented function `norm`. Thanks Rogelio J. Baucells (@rjbaucells).
- Improved function `ifElse`, is now specified for special data types too.
- Improved function `det`. Thanks Bryan Cuccioli (@bcuccioli).
- Implemented `BigNumber` support for functions `det` and `diag`.
- Added unit alias `lbs` (pound mass).
- Changed configuration option `decimals` to `precision` (applies to BigNumbers
  only).
- Fixed support for element-wise comparisons between a string and a matrix.
- Fixed: expression parser now trows IndexErrors with one-based indices instead
  of zero-based.
- Minor bug fixes.


## 2014-03-30, version 0.19.0

- Implemented functions `compare`, `sum`, `prod`, `var`, `std`, `median`.
- Implemented function `ifElse` Thanks @mtraynham.
- Minor bug fixes.


## 2014-02-15, version 0.18.1

- Added unit `feet`.
- Implemented function `compile` (shortcut for parsing and then compiling).
- Improved performance of function `pow` for matrices. Thanks @hamadu.
- Fixed broken auto completion in the command line interface.
- Fixed an error in function `combinations` for large numbers, and
  improved performance of both functions `combinations` and `permutations`.


## 2014-01-18, version 0.18.0

- Changed matrix index notation of expression parser from round brackets to
  square brackets, for example `A[1, 1:3]` instead of `A(1, 1:3)`.
- Removed need to use the `function` keyword for function assignments in the
  expression parser, you can define a function now like `f(x) = x^2`.
- Implemented a compilation step in the expression parser: expressions are
  compiled into JavaScript, giving much better performance (easily 10x as fast).
- Renamed unit conversion function and operator `in` to `to`. Operator `in` is
  still available in the expression parser as an alias for `to`. Added unit
  `in`, an abbreviation for `inch`. Thanks Elijah Insua (@tmpvar).
- Added plurals and aliases for units.
- Implemented an argument `includeEnd` for function `range` (false by default).
- Ranges in the expression parser now support big numbers.
- Implemented functions `permutations` and `combinations`.
  Thanks Daniel Levin (@daniel-levin).
- Added lower case abbreviation `l` for unit litre.


## 2013-12-19, version 0.17.1

- Fixed a bug with negative temperatures.
- Fixed a bug with prefixes of units squared meter `m2` and cubic meter `m3`.


## 2013-12-12, version 0.17.0

- Renamed and flattened configuration settings:
  - `number.defaultType` is now `number`.
  - `number.precision` is now `decimals`.
  - `matrix.defaultType` is now `matrix`.
- Function `multiply` now consistently outputs a complex number on complex input.
- Fixed `mod` and `in` not working as function (only as operator).
- Fixed support for old browsers (IE8 and older), compatible when using es5-shim.
- Fixed support for Java's ScriptEngine.


## 2013-11-28, version 0.16.0

- Implemented BigNumber support for arbitrary precision calculations.
  Added settings `number.defaultType` and `number.precision` to configure
  big numbers.
- Documentation is extended.
- Removed utility functions `isScalar`, `toScalar`, `isVector`, `toVector`
  from `Matrix` and `Range`. Use `math.squeeze` and `math.size` instead.
- Implemented functions `get` and `set` on `Matrix`, for easier and faster
  retrieval/replacement of elements in a matrix.
- Implemented function `resize`, handling matrices, scalars, and strings.
- Functions `ones` and `zeros` now return an empty matrix instead of a
  number 1 or 0 when no arguments are provided.
- Implemented functions `min` and `max` for `Range` and `Index`.
- Resizing matrices now leaves new elements undefined by default instead of
  filling them with zeros. Function `resize` now has an extra optional
  parameter `defaultValue`.
- Range operator `:` in expression parser has been given a higher precedence.
- Functions don't allow arguments of unknown type anymore.
- Options be set when constructing a math.js instance or using the new function
  `config(options`. Options are no longer accessible via `math.options`.
- Renamed `scientific` notation to `exponential` in function `format`.
- Function `format` outputs exponential notation with positive exponents now
  always with `+` sign, so outputs `2.1e+3` instead of `2.1e3`.
- Fixed function `squeeze` not being able squeeze into a scalar.
- Some fixes and performance improvements in the `resize` and `subset`
  functions.
- Function `size` now adheres to the option `matrix.defaultType` for scalar
  input.
- Minor bug fixes.


## 2013-10-26, version 0.15.0

- Math.js must be instantiated now, static calls are no longer supported. Usage:
  - node.js: `var math = require('mathjs')();`
  - browser: `var math = mathjs();`
- Implemented support for multiplying vectors with matrices.
- Improved number formatting:
  - Function `format` now support various options: precision, different
    notations (`fixed`, `scientific`, `auto`), and more.
  - Numbers are no longer rounded to 5 digits by default when formatted.
  - Implemented a function `format` for `Matrix`, `Complex`, `Unit`, `Range`,
    and `Selector` to format using options.
  - Function `format` does only stringify values now, and has a new parameter
    `precision` to round to a specific number of digits.
  - Removed option `math.options.precision`,
    use `math.format(value [, precision])` instead.
  - Fixed formatting numbers as scientific notation in some cases returning
    a zero digit left from the decimal point. (like "0.33333e8" rather than
    "3.3333e7"). Thanks @husayt.
- Implemented a function `print` to interpolate values in a template string,
  this functionality was moved from the function `format`.
- Implemented statistics function `mean`. Thanks Guillermo Indalecio Fernandez
  (@guillermobox).
- Extended and changed `max` and `min` for multi dimensional matrices: they now
  return the maximum and minimum of the flattened array. An optional second
  argument `dim` allows to calculate the `max` or `min` for specified dimension.
- Renamed option `math.options.matrix.default` to
  `math.options.matrix.defaultType`.
- Removed support for comparing complex numbers in functions `smaller`,
  `smallereq`, `larger`, `largereq`. Complex numbers cannot be ordered.


## 2013-10-08, version 0.14.0

- Introduced an option `math.options.matrix.default` which can have values
  `matrix` (default) or `array`. This option is used by the functions `eye`,
  `ones`, `range`, and `zeros`, to determine the type of matrix output.
- Getting a subset of a matrix will automatically squeeze the resulting subset,
  setting a subset of a matrix will automatically unsqueeze the given subset.
- Removed concatenation of nested arrays in the expression parser.
  You can now input nested arrays like in JavaScript. Matrices can be
  concatenated using the function `concat`.
- The matrix syntax `[...]` in the expression parser now creates 1 dimensional
  matrices by default. `math.eval('[1,2,3,4]')` returns a matrix with
  size `[4]`, `math.eval('[1,2;3,4]')` returns a matrix with size `[2,2]`.
- Documentation is restructured and extended.
- Fixed non working operator `mod` (modulus operator).


## 2013-09-03, version 0.13.0

- Implemented support for booleans in all relevant functions.
- Implemented functions `map` and `forEach`. Thanks Sebastien Piquemal (@sebpic).
- All construction functions can be used to convert the type of variables,
  also element-wise for all elements in an Array or Matrix.
- Changed matrix indexes of the expression parser to one-based with the
  upper-bound included, similar to most math applications. Note that on a
  JavaScript level, math.js uses zero-based indexes with excluded upper-bound.
- Removed support for scalars in the function `subset`, it now only supports
  Array, Matrix, and String.
- Removed the functions `get` and `set` from a selector, they are a duplicate
  of the function `subset`.
- Replaced functions `get` and `set` of `Matrix` with a single function
  `subset`.
- Some moving around with code and namespaces:
  - Renamed namespace `math.expr` to `math.expression` (contains Scope, Parser,
    node objects).
  - Renamed namespace `math.docs` to `math.expression.docs`.
  - Moved `math.expr.Selector` to `math.chaining.Selector`.
- Fixed some edge cases in functions `lcm` and `xgcd`.


## 2013-08-22, version 0.12.1

- Fixed outdated version of README.md.
- Fixed a broken unit test.


## 2013-08-22, version 0.12.0

- Implemented functions `random([min, max])`, `randomInt([min, max])`,
  `pickRandom(array)`. Thanks Sebastien Piquemal (@sebpic).
- Implemented function `distribution(name)`, generating a distribution object
  with functions `random`, `randomInt`, `pickRandom` for different
  distributions. Currently supporting `uniform` and `normal`.
- Changed the behavior of `range` to exclude the upper bound, so `range(1, 4)`
  now returns `[1, 2, 3]` instead of `[1, 2, 3, 4]`.
- Changed the syntax of `range`, which is now `range(start, end [, step])`
  instead of `range(start, [step, ] end)`.
- Changed the behavior of `ones` and `zeros` to geometric dimensions, for
  example `ones(3)` returns a vector with length 3, filled with ones, and
  `ones(3,3)` returns a 2D array with size [3, 3].
- Changed the return type of `ones` and `zeros`: they now return an Array when
  arguments are Numbers or an Array, and returns a Matrix when the argument
  is a Matrix.
- Change matrix index notation in parser from round brackets to square brackets,
  for example `A[0, 0:3]`.
- Removed the feature introduced in v0.10.0 to automatically convert a complex
  value with an imaginary part equal to zero to a number.
- Fixed zeros being formatted as null. Thanks @TimKraft.


## 2013-07-23, version 0.11.1

- Fixed missing development dependency


## 2013-07-23, version 0.11.0

- Changed math.js from one-based to zero-based indexes.
  - Getting and setting matrix subset is now zero-based.
  - The dimension argument in function `concat` is now zero-based.
- Improvements in the string output of function help.
- Added constants `true` and `false`.
- Added constructor function `boolean`.
- Fixed function `select` not accepting `0` as input.
  Thanks Elijah Manor (@elijahmanor).
- Parser now supports multiple unary minus operators after each other.
- Fixed not accepting empty matrices like `[[], []]`.
- Some fixes in the end user documentation.


## 2013-07-08, version 0.10.0

- For complex calculations, all functions now automatically replace results
  having an imaginary part of zero with a Number. (`2i * 2i` now returns a
  Number `-4` instead of a Complex `-4 + 0i`).
- Implemented support for injecting custom node handlers in the parser. Can be
  used for example to implement a node handler for plotting a graph.
- Implemented end user documentation and a new `help` function.
- Functions `size` and `squeeze` now return a Matrix instead of an Array as
  output on Matrix input.
- Added a constant tau (2 * pi). Thanks Zak Zibrat (@palimpsests).
- Renamed function `unaryminus` to `unary`.
- Fixed a bug in determining node dependencies in function assignments.


## 2013-06-14, version 0.9.1

- Implemented element-wise functions and operators: `emultiply` (`x .* y`),
  `edivide` (`x ./ y`), `epow` (`x .^ y`).
- Added constants `Infinity` and `NaN`.
- Removed support for Workspace to keep the library focused on its core task.
- Fixed a bug in the Complex constructor, not accepting NaN values.
- Fixed division by zero in case of pure complex values.
- Fixed a bug in function multiply multiplying a pure complex value with
  Infinity.


## 2013-05-29, version 0.9.0

- Implemented function `math.parse(expr [,scope])`. Optional parameter scope can
  be a plain JavaScript Object containing variables.
- Extended function `math.expr(expr [, scope])` with an additional parameter
  `scope`, similar to `parse`. Example: `math.eval('x^a', {x:3, a:2});`.
- Implemented function `subset`, to get or set a subset from a matrix, string,
  or other data types.
- Implemented construction functions number and string (mainly useful inside
  the parser).
- Improved function `det`. Thanks Bryan Cuccioli (@bcuccioli).
- Moved the parse code from prototype math.expr.Parser to function math.parse,
  simplified Parser a little bit.
- Strongly simplified the code of Scope and Workspace.
- Fixed function mod for negative numerators, and added error messages in case
  of wrong input.


## 2013-05-18, version 0.8.2

- Extended the import function and some other minor improvements.
- Fixed a bug in merging one dimensional vectors into a matrix.
- Fixed a bug in function subtract, when subtracting a complex number from a
  real number.


## 2013-05-10, version 0.8.1

- Fixed an npm warning when installing mathjs globally.


## 2013-05-10, version 0.8.0

- Implemented a command line interface. When math.js is installed globally via
  npm, the application is available on your system as 'mathjs'.
- Implemented `end` keyword for index operator, and added support for implicit
  start and end (expressions like `a(2,:)` and `b(2:end,3:end-1)` are supported
  now).
- Function math.eval is more flexible now: it supports variables and multi-line
  expressions.
- Removed the read-only option from Parser and Scope.
- Fixed non-working unequal operator != in the parser.
- Fixed a bug in resizing matrices when replacing a subset.
- Fixed a bug in updating a subset of a non-existing variable.
- Minor bug fixes.


## 2013-05-04, version 0.7.2

- Fixed method unequal, which was checking for equality instead of inequality.
  Thanks @FJS2.


## 2013-04-27, version 0.7.1

- Improvements in the parser:
  - Added support for chained arguments.
  - Added support for chained variable assignments.
  - Added a function remove(name) to remove a variable from the parsers scope.
  - Renamed nodes for more consistency and to resolve naming conflicts.
  - Improved stringification of an expression tree.
  - Some simplifications in the code.
  - Minor bug fixes.
- Fixed a bug in the parser, returning NaN instead of throwing an error for a
  number with multiple decimal separators like `2.3.4`.
- Fixed a bug in Workspace.insertAfter.
- Fixed: math.js now works on IE 6-8 too.


## 2013-04-20, version 0.7.0

- Implemented method `math.eval`, which uses a readonly parser to evaluate
  expressions.
- Implemented method `xgcd` (extended eucledian algorithm). Thanks Bart Kiers
  (@bkiers).
- Improved math.format, which now rounds values to a maximum number of digits
  instead of decimals (default is 5 digits, for example `math.format(math.pi)`
  returns `3.1416`).
- Added examples.
- Changed methods square and cube to evaluate matrices element wise (consistent
  with all other methods).
- Changed second parameter of method import to an object with options.
- Fixed method math.typeof on IE.
- Minor bug fixes and improvements.


## 2013-04-13, version 0.6.0

- Implemented chained operations via method math.select(). For example
  `math.select(3).add(4).subtract(2).done()` will return `5`.
- Implemented methods gcd and lcm.
- Implemented method `Unit.in(unit)`, which creates a clone of the unit with a
  fixed representation. For example `math.unit('5.08 cm').in('inch')` will
  return a unit which string representation always is in inch, thus `2 inch`.
  `Unit.in(unit)` is the same as method `math.in(x, unit)`.
- Implemented `Unit.toNumber(unit)`, which returns the value of the unit when
  represented with given unit. For example
  `math.unit('5.08 cm').toNumber('inch')` returns the number `2`, as the
  representation of the unit in inches has 2 as value.
- Improved: method `math.in(x, unit)` now supports a string as second parameter,
  for example `math.in(math.unit('5.08 cm'), 'inch')`.
- Split the end user documentation of the parser functions from the source
  files.
- Removed function help and the built-in documentation from the core library.
- Fixed constant i being defined as -1i instead of 1i.
- Minor bug fixes.


## 2013-04-06, version 0.5.0

- Implemented data types Matrix and Range.
- Implemented matrix methods clone, concat, det, diag, eye, inv, ones, size,
  squeeze, transpose, zeros.
- Implemented range operator `:`, and transpose operator `'` in parser.
- Changed: created construction methods for easy object creation for all data
  types and for the parser. For example, a complex value is now created
  with `math.complex(2, 3)` instead of `new math.Complex(2, 3)`, and a parser
  is now created with `math.parser()` instead of `new math.parser.Parser()`.
- Changed: moved all data types under the namespace math.type, and moved the
  Parser, Workspace, etc. under the namespace math.expr.
- Changed: changed operator precedence of the power operator:
  - it is now right associative instead of left associative like most scripting
    languages. So `2^3^4` is now calculated as `2^(3^4)`.
  - it has now higher precedence than unary minus most languages, thus `-3^2` is
    now calculated as `-(3^2)`.
- Changed: renamed the parsers method 'put' into 'set'.
- Fixed: method 'in' did not check for units to have the same base.


## 2013-03-16, version 0.4.0

- Implemented Array support for all methods.
- Implemented Array support in the Parser.
- Implemented method format.
- Implemented parser for units, math.Unit.parse(str).
- Improved parser for complex values math.Complex.parse(str);
- Improved method help: it now evaluates the examples.
- Fixed: a scoping issue with the Parser when defining functions.
- Fixed: method 'typeof' was not working well with minified and mangled code.
- Fixed: errors in determining the best prefix for a unit.


## 2013-03-09, version 0.3.0

- Implemented Workspace
- Implemented methods cot, csc, sec.
- Implemented Array support for methods with one parameter.


## 2013-02-25, version 0.2.0

- Parser, Scope, and expression tree with Nodes implemented.
- Implemented method import which makes it easy to extend math.js.
- Implemented methods arg, conj, cube, equal, factorial, im, largereq,
  log(x, base), log10, mod, re, sign, smallereq, square, unequal.


## 2013-02-18, version 0.1.0

- Reached full compatibility with Javascripts built-in Math library.
- More functions implemented.
- Some bugfixes.


## 2013-02-16, version 0.0.2

- All constants of Math implemented, plus the imaginary unit i.
- Data types Complex and Unit implemented.
- First set of functions implemented.


## 2013-02-15, version 0.0.1

- First publish of the mathjs package. (package is still empty)
