/usr/share/psychtoolbox-3/PsychSignal/BoolFromSNR.m is in psychtoolbox-3-common 3.0.11.20131230.dfsg1-1build1.
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1 2 3 4 5 6 7 8 9 10 11 12 | function q = BoolFromSNR(SNR,n)
% creates a boolean (selection) vector from an SNR (Signal-to-Noise Ratio)
% q = BoolFromSNR(SNR,n)
% 2008 DN Wrote it.
% compute which proportion is signal for this SNR
prop = (SNR)/(SNR+1);
% a percentage will be randomized to achieve the SNR
inds = NRandPerm(n,round(n.*(1-prop)));
q = ismember([1:n],inds);
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