multidim-array-index
maps multidimensional array indices to monodimensional array index
Table Of Contents:
Installation
With npm do
npm install multidim-array-index
Examples
All code in the examples below is intended to be contained into a single file.
var multiDimArrayIndex = require('multidim-array-index')
1th-order
In the monodimensional case, it just returns the index itself.
var i3 = multiDimArrayIndex.bind(null, [3])
i3([0]) // 0
i3([1]) // 1
i3([2]) // 2
2th-order
For a two dimensional case, for instance a matrix, it is equivalent to the
function (i, j, numCols) => j + i * numCols
var i2x3 = multiDimArrayIndex.bind(null, [2, 3])
i2x3([0, 0]) // 0
i2x3([0, 1]) // 1
i2x3([0, 2]) // 2
i2x3([1, 0]) // 3
i2x3([1, 1]) // 4
i2x3([1, 2]) // 5
3th-order
var i2x3x4 = multiDimArrayIndex.bind(null, [2, 2, 2])
i2x3x4([0, 0, 0]) // 0
i2x3x4([0, 0, 1]) // 1
i2x3x4([0, 0, 2]) // 2
i2x3x4([0, 0, 3]) // 3
i2x3x4([0, 1, 0]) // 4
i2x3x4([0, 1, 1]) // 5
i2x3x4([0, 1, 2]) // 6
i2x3x4([0, 1, 3]) // 7
i2x3x4([1, 0, 0]) // 8
i2x3x4([1, 0, 1]) // 9
i2x3x4([1, 0, 2]) // 10
i2x3x4([1, 0, 3]) // 11
i2x3x4([1, 1, 0]) // 12
i2x3x4([1, 1, 1]) // 13
i2x3x4([1, 1, 2]) // 14
i2x3x4([1, 1, 3]) // 15
i2x2x2([0, 0, 0]) //// 0
i2x2x2([0, 0, 1]) // 1
i2x2x2([0, 1, 0]) // 2
i2x2x2([0, 1, 1]) // 3
i2x2x2([1, 0, 0]) // 4
i2x2x2([1, 0, 1]) // 5
i2x2x2([1, 1, 0]) // 6
i2x2x2([1, 1, 1]) // 7
API
multiDimArrayIndex(dimension, indices)
- @param
{Array}dimensions defines the shape of the multi dimensional array - @param
{Array}indices to transform - @returns
{Number}index of an equivalent mono dimensional array
Given dimensions d_1, d_2, d_3 .. d_n and indices i_1, i_2, i_3 .. i_n index
is computed by formula
index = i_n + i_(n-1) * d_n + i_(n-2) * d_n * d_(n-1) + ... + i_2 * d_n * d_(n-1) * ... * d_3 + i_1 * d_n * ... * d_2
multiDimArrayIndex.error
An object exposing the following error messages:
- outOfBoundIndex
For example, the following snippets will throw
// outOfBoundIndex
i3([11])
i2x3x4([2, 3, 5])