view general/numerical/scalar/safe_exp2.m @ 61:eff6bddf82e3 tip

Finally implemented perceptual brightness thing.

function [y,k]=safe_exp2(x,l)
% safe_exp2 - high dynamic range exponential
%
% safe_exp2 :: X:[[N,M]], L:real -> [[N,M]], [[1,M]].
%
% returns y and k such that exp(X) = y * exp(k) and
% maximum value in y is exp(L).
% Maximum sensible value of L is log(realmax)=709.78.

k=max(x,[],1)-l; 
y=exp(x-repmat(k,size(x,1),1));