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Matlab-Code-for-Rep-Prog-Phys/

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Matlab-Code-for-Rep-Prog-Phys/**logNsamplin.m**

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% function [xp yp] = logNsamp(x,f,N) | |

% x is the x-data with even linear spacing | |

% f is the function value for the x values | |

% NOTE: f should be on linear scale, because logNsample takes log(f) | |

% N is the number of divisions | |

% | |

% xp is evenly spaced on log | |

% yp is function value on xp | |

% NOTE: Size of xp and yp is 1:N+1 which includes the endpoints | |

% xp(1) = log(x(1)) and xp(N+1) = log(x(szx)) | |

% | |

% See also logevendist.m | |

function [xp yp] = logNsamplin(x,f,N) | |

[dum sz] = size(f); | |

n = 1:N+1; % | |

logx = log(x); | |

%logf = log(f); | |

delx = x(2) - x(1); | |

delogx = diff(logx); | |

delxp = (log(x(sz)) - log(x(1)))/N; | |

xp = log(x(1)) + (n-1).*delxp; % | |

yp = zeros(size(xp)); | |

%keyboard | |

[X, I] = changesign(delxp - 2*delogx); | |

I; %cross-over location between needing to interpolate versus needing to average | |

%ind = floor(logx(I)/delxp); | |

ind = floor((logx(I)-logx(1))/delxp); | |

%keyboard | |

yplo = intersamp(logx(1:I+1),f(1:I+1),xp(1:ind+1)); | |

yphi = avgsamp(logx(I+1:sz),f(I+1:sz),xp(ind+1:N)); | |

%keyboard | |

yp(1:ind+1) = (yplo(1:ind+1)); | |

yp(ind+2) = (0.5*(yplo(ind+1)+ yphi(2))); | |

yp(ind+3:N+1) = (yphi(2:(N-ind))); | |

%keyboard | |

function [X, I] = changesign(a) | |

[dum sz1] = size(a); | |

b(1:(sz1-1)) = a(2:sz1); | |

tst = a(1:(sz1-1)).*b; | |

[X, Itmp] = min(tst); | |

I = Itmp + 1; | |

function y = intersamp(x,f,xp) | |

y = interp1(x,f,xp,'linear','extrap'); | |

function y = avgsamp(x,f,xp) | |

[dum szx] = size(x); | |

[dum szp] = size(xp); | |

delxp = xp(2) - xp(1); | |

%keyboard | |

fcum = zeros(1,szp); | |

cnt = zeros(1,szp); | |

for loop = 1:szx | |

bin = ceil((x(loop)-(xp(1) + 0.5*delxp))/delxp); % | |

%keyboard | |

if bin>0 | |

fcum(bin) = fcum(bin) + f(loop); | |

cnt(bin) = cnt(bin) + 1; | |

end | |

end | |

for loop = 1:szp | |

if cnt(loop) ~=0 | |

fav(loop) = fcum(loop)/cnt(loop); | |

else | |

fav(loop) = 0; | |

end | |

end | |

y = fav; | |