mp.m

来自「％ Atomizer Main Directory, Version .802 」· M 代码 · 共 65 行

function coef = MP(x, NameOfDict, par1, par2, par3, natom, frac)
% MP.m -- Matching Pursuit
%  Usage
%	coef = MP(x, NameOfDict, par1, par2, par3[, natom, frac])
%  Input
%	x		1-d signal; n-by-1 column vector
%	NameOfDict	string; name of the dictionary
%	par1,par2,par3	parameters of the dictionary
%	natom    	max # of atoms desired, default = n
%	frac     	min fraction total signal energy to enter, default=1e-2
%
%	Use 'help dictionary' for dictionary objects: NameOfDict,par1,par2,par3
%  Outputs
%	coef		coef of the MP representation; column vector
%  Description
%	1. natom controls the maximum number of atoms MP can select
%	2. Selected atoms must have coefficients greater than a certain
%	   fraction of total signal energy, defined by the parameter
%	   frac, in order to be enter.
%  See Also
%	OMP, MP_Matrix, OMP_Matrix
%

x = x(:);
n = length(x);

if nargin < 7,
	frac = 1e-2;
end
if nargin < 6,
	natom = n;
end


[m L] = SizeOfDict(n, NameOfDict, par1, par2, par3);
zerosm = zeros(m,1);
nrm = norm(x);
amp = nrm;

residule = x;
coef = [];
index = [];
k = 0;
fprintf('\nMP:\n');
while (amp > frac*nrm) & (k < natom),
	c = FastA(residule, NameOfDict, par1, par2, par3);
	[amp i] = max(abs(c));
	i = i(1);
	index = [index; i];
	coefnew = c(i);
	coef = [coef; coefnew];
	temp = zerosm; temp(i) = 1;
	residule = residule - coefnew * FastS(temp, n, NameOfDict, par1, par2, par3);
	k = k + 1;
	disp(sprintf('Step%4g:  select = %5g     coef = %10.2e',k,i,coefnew));
end

h = length(coef);
coefbest = zeros(m, 1);
for i = 1:h,
	coefbest(index(i)) = coefbest(index(i)) + coef(i);
end
coef = coefbest;