diag

Extract the diagonal from an array. More...

Functions
AFAPI array	diag (const array &in, const int num=0, const bool extract=true)
	C++ Interface to extract the diagonal from an array. More...
AFAPI af_err	af_diag_create (af_array *out, const af_array in, const int num)
	C Interface to create a diagonal matrix from an extracted diagonal array. More...
AFAPI af_err	af_diag_extract (af_array *out, const af_array in, const int num)
	C Interface to extract the diagonal from an array. More...

Detailed Description

Extract the diagonal from an array.

If extract is true, an array is extracted containing diagonal of the matrix, while a false condition returns a diagonal matrix.

// 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
	)

C Interface to create a diagonal matrix from an extracted diagonal array.

See also, af_diag_extract.

Parameters

[out]	out	diagonal matrix
[in]	in	diagonal array
[in]	num	diagonal index

Returns

AF_SUCCESS, if function returns successfully, else an af_err code is given

af_diag_extract()

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

C Interface to extract the diagonal from an array.

See also, af_diag_create.

Parameters

[out]	out	num-th diagonal array
[in]	in	input array
[in]	num	diagonal index

Returns

AF_SUCCESS, if function returns successfully, else an af_err code is given

diag()

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

C++ Interface to extract the diagonal from an array.

Parameters

[in]	in	input array
[in]	num	diagonal index
[in]	extract	if true, returns an array containing diagonal of the matrix; if false, returns a diagonal matrix

Returns

diagonal array (or matrix)