matfaust::proj::spsymm Class Reference

Functor for the SPSYMM projector. More...

Public Member Functions
function	spsymm (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 SPSYMM projector.

A, the image matrix of M, is such that A is symmetric and \( k \le \| A \|_0 \le k + 1, \| A\|_F = 1 \) (if normalized == True), assuming that \(\| M \|_0 >= k\).

Usage

    spsymm(shape, k): returns a SPSYMM 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).
    spsymm(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. The result might be k+1 nonzeros in case of an odd number of nonzeros on the diagonal.
'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 spsymm projector.

Example

>> import matfaust.proj.spsymm
>> rng(42) % for reproducibility
>> M = rand(5, 5);
>> p = spsymm(size(M), 2);
>> p(M)
 
ans =
 
         0         0         0         0         0
         0         0    0.7071         0         0
         0    0.7071         0         0         0
         0         0         0         0         0
         0         0         0         0         0
 
>>

Constructor & Destructor Documentation

spsymm()

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

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

• spsymm.m