mirror of
https://github.com/josdejong/mathjs.git
synced 2026-01-18 14:59:29 +00:00
0db42306ec
* initial implementation of multidimensional std and var * consolidated std function into var, cleaned up the interface for var, fixed bias correction * added documentation of variable axis for std and var * updated documentation for std and var * changed the order of normalization and dimension for a three parameter input in the functions * updated documentation for var and std * add transform expressions for std and var with variable axis * added test coverage for std and var with a variable axis * update to documentation * change n dim std to use apply function * fixed tests, removed unnecessary code, updated docs * fixed typo in docs * update docs to remove a type * changed location of apply function * updated tests to use deepStrictEqual to pass linter * adding test coverage for var.transform and std.transform
2.0 KiB
2.0 KiB
Function var
Compute the variance of a matrix or a list with values. In case of a (multi dimensional) array or matrix, the variance over all elements will be calculated.
Additionally, it is possible to compute the variance along the rows or columns of a matrix by specifying the dimension as the second argument.
Optionally, the type of normalization can be specified as the final
parameter. The parameter normalization can be one of the following values:
- 'unbiased' (default) The sum of squared errors is divided by (n - 1)
- 'uncorrected' The sum of squared errors is divided by n
- 'biased' The sum of squared errors is divided by (n + 1)
Note that older browser may not like the variable name var. In that
case, the function can be called as math['var'](...) instead of
math.var(...).
Syntax
math.var(a, b, c, ...)
math.var(A)
math.var(A, normalization)
math.var(A, dimension)
math.var(A, dimension, normalization)
Parameters
| Parameter | Type | Description |
|---|---|---|
array |
Array | Matrix | A single matrix or or multiple scalar values |
normalization |
string | Determines how to normalize the variance. Choose 'unbiased' (default), 'uncorrected', or 'biased'. Default value: 'unbiased'. |
Returns
| Type | Description |
|---|
- | The variance
Examples
math.var(2, 4, 6) // returns 4
math.var([2, 4, 6, 8]) // returns 6.666666666666667
math.var([2, 4, 6, 8], 'uncorrected') // returns 5
math.var([2, 4, 6, 8], 'biased') // returns 4
math.var([[1, 2, 3], [4, 5, 6]]) // returns 3.5
math.var([[1, 2, 3], [4, 6, 8]], 0) // returns [4.5, 8, 12.5]
math.var([[1, 2, 3], [4, 6, 8]], 1) // returns [1, 4]
math.var([[1, 2, 3], [4, 6, 8]], 1, 'biased') // returns [0.5, 2]