matfaust::proj::sptril Class Reference

Functor for the SPTRIL projector. More...

Public Member Functions
function	sptril (shape, k, varargin)
Public Member Functions inherited from matfaust::proj::proj_gen
function	subsref (self, S)

Additional Inherited Members
Protected Attributes inherited from matfaust::proj::proj_gen
Property	constraint

Detailed Description

Functor for the SPTRIL projector.

A, the image matrix, is such that the upper triangular part is 0 and \( \| A \|_0 = k, \| A\|_F = 1 \) (if normalized == True).

Usage

    sptril(shape, k): returns a SPTRIL projector (functor), shape defines the size of the input matrix (e.g. [1, 10]), k defines the sparsity of the output matrix (k nnz coefficients).
    sptril(shape,k,'normalized', bool,'pos', bool): the optional parameters are set. By default both normalized and pos are false.

Parameters

shape	vector of size 2, to define the size of the input matrix.
k	the sparsity parameter (the number of nonzeros of the projection image.
'normalized',true	normalizes the projection image according to its Frobenius norm.
'normalized',false	(the default) no normalization.
'pos',true	skips the negative values (replaced by zero) of the input matrix.
'pos',false	(the default) negative values are not skipped.

Return values

proj	the sptril projector.

Example

>> import matfaust.proj.sptril
>> rng(42) % reproducibility
>> M = rand(5, 5);
>> p = sptril(size(M), 2);
>> p(M)
 
ans =
 
         0         0         0         0         0
    0.7392         0         0         0         0
         0    0.6735         0         0         0
         0         0         0         0         0
         0         0         0         0         0
 
>>

see also matfaust.proj.sptriu

Constructor & Destructor Documentation

sptril()

function matfaust::proj::sptril::sptril	(	shape	,
		k	,
		varargin
	)

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The documentation for this class was generated from the following file:

• sptril.m