71 lines
2.1 KiB
Markdown
71 lines
2.1 KiB
Markdown
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<!-- Note: This file is automatically generated from source code comments. Changes made in this file will be overridden. -->
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# Function diff
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Create a new matrix or array of the difference between elements of the given array
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The optional dim parameter lets you specify the dimension to evaluate the difference of
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If no dimension parameter is passed it is assumed as dimension 0
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Dimension is zero-based in javascript and one-based in the parser and can be a number or bignumber
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Arrays must be 'rectangular' meaning arrays like [1, 2]
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If something is passed as a matrix it will be returned as a matrix but other than that all matrices are converted to arrays
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## Syntax
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```js
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math.diff(arr)
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math.diff(arr, dim)
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```
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### Parameters
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Parameter | Type | Description
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--------- | ---- | -----------
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`arr` | Array | Matrix | An array or matrix
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`dim` | number | Dimension
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### Returns
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Type | Description
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---- | -----------
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Array | Matrix | Difference between array elements in given dimension
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### Throws
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Type | Description
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---- | -----------
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## Examples
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```js
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const arr = [1, 2, 4, 7, 0]
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math.diff(arr) // returns [1, 2, 3, -7] (no dimension passed so 0 is assumed)
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math.diff(math.matrix(arr)) // returns math.matrix([1, 2, 3, -7])
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const arr = [[1, 2, 3, 4, 5], [1, 2, 3, 4, 5], [9, 8, 7, 6, 4]]
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math.diff(arr) // returns [[0, 0, 0, 0, 0], [8, 6, 4, 2, -1]]
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math.diff(arr, 0) // returns [[0, 0, 0, 0, 0], [8, 6, 4, 2, -1]]
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math.diff(arr, 1) // returns [[1, 1, 1, 1], [1, 1, 1, 1], [-1, -1, -1, -2]]
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math.diff(arr, math.bignumber(1)) // returns [[1, 1, 1, 1], [1, 1, 1, 1], [-1, -1, -1, -2]]
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math.diff(arr, 2) // throws RangeError as arr is 2 dimensional not 3
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math.diff(arr, -1) // throws RangeError as negative dimensions are not allowed
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// These will all produce the same result
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math.diff([[1, 2], [3, 4]])
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math.diff([math.matrix([1, 2]), math.matrix([3, 4])])
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math.diff([[1, 2], math.matrix([3, 4])])
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math.diff([math.matrix([1, 2]), [3, 4]])
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// They do not produce the same result as math.diff(math.matrix([[1, 2], [3, 4]])) as this returns a matrix
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```
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## See also
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[sum](sum.md),
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[subtract](subtract.md),
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[partitionSelect](partitionSelect.md)
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