calcxnu.m

来自「一种基于压缩感知技术的图像重建程序」· M 代码 · 共 31 行

function xnu = CalcXnu(nu)
% xnu = CalcXnu(nu)
% solve (1-nu)/nu = 2 G(xnu) xnu/g(xnu)  
% G is PDF of halfnormal with variance 1/2. i.e. erf!
% Eqn (4.2) of HDCSPwNP2N

% check that nu is in range.
if max(nu(:)) >= 1 | min( nu(:)) <= 0,
    disp(' Error in CalcXnu: nu outside (0,1) ')
end

% build table 
xxnu = linspace(0,12,500);
pnu = erf(xxnu);
eden = 2.*exp(-xxnu.^2)./sqrt(pi);    % density of erf
gxnu = xxnu .* pnu ./eden  ;          % left side of (4.2)*2
wnu = (1-nu)./(2.*nu);                % right side of (4.2)/2
xnu = interp1(gxnu,xxnu,wnu);         % x making left = right 

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% Copyright (c) 2006. David Donoho
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% Part of SparseLab Version:100
% Created Tuesday March 28, 2006
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