diag

Extract diagonal from a matrix when extract is set to true. More...

Functions
AFAPI array	diag (const array &in, const int num=0, const bool extract=true)
AFAPI af_err	af_diag_create (af_array *out, const af_array in, const int num)
AFAPI af_err	af_diag_extract (af_array *out, const af_array in, const int num)

Detailed Description

Extract diagonal from a matrix when extract is set to true.

Create a diagonal matrix from input array when extract is set to false

// Extraction
array a = randu(dim4(4, 3));
// a [4 3 1 1]
// 0.0000     0.5328     0.6793
// 0.1315     0.2190     0.9347
// 0.7556     0.0470     0.3835
// 0.4587     0.6789     0.5194
 
array b = diag(a);
// b [3 1 1 1]
// 0.0000
// 0.2190
// 0.3835
 
array c = diag(a, 1);
// c [2 1 1 1]
// 0.5328
// 0.9347
 
// Creation
array a = randu(4);
// a [4 1 1 1]
// 0.0000
// 0.1315
// 0.7556
// 0.4587
 
array b = diag(a, 0, false);
// b [4 4 1 1]
// 0.0000     0.0000     0.0000     0.0000
// 0.0000     0.1315     0.0000     0.0000
// 0.0000     0.0000     0.7556     0.0000
// 0.0000     0.0000     0.0000     0.4587
 
array b = diag(a, -1, false);
// c [5 5 1 1]
// 0.0000     0.0000     0.0000     0.0000     0.0000
// 0.0000     0.0000     0.0000     0.0000     0.0000
// 0.0000     0.1315     0.0000     0.0000     0.0000
// 0.0000     0.0000     0.7556     0.0000     0.0000
// 0.0000     0.0000     0.0000     0.4587     0.0000

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Function Documentation

af_diag_create()

AFAPI af_err af_diag_create	(	af_array *	out,
		const af_array	in,
		const int	num
	)

Parameters

[out]	out	is the array created from the input array in
[in]	in	is the input array which is the diagonal
[in]	num	is the diagonal index

af_diag_extract()

AFAPI af_err af_diag_extract	(	af_array *	out,
		const af_array	in,
		const int	num
	)

Parameters

[out]	out	is the num -th diagonal of in
[in]	in	is the input matrix
[in]	num	is the diagonal index

diag()

AFAPI array diag	(	const array &	in,
		const int	num = 0,
		const bool	extract = true
	)

Parameters

[in]	in	is the input array
[in]	num	is the diagonal index
[in]	extract	when true returns an array containing diagonal of tha matrix and when false returns a matrix with in as diagonal

Returns

an array with either the diagonal or the matrix based on extract