/usr/share/octave/packages/nan-2.8.1/normpdf.m is in octave-nan 2.8.1-1ubuntu2.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 | function p = normpdf(x,m,s)
% NORMPDF returns normal probability density
%
% pdf = normpdf(x,m,s);
%
% Computes the PDF of a the normal distribution
% with mean m and standard deviation s
% default: m=0; s=1;
% x,m,s must be matrices of same size, or any one can be a scalar.
%
% see also: NORMCDF, NORMINV
% Reference(s):
% $Id: normpdf.m 9033 2011-11-08 20:58:07Z schloegl $
% Copyright (C) 2000-2003,2010,2011 by Alois Schloegl <alois.schloegl@gmail.com>
% This function is part of the NaN-toolbox
% http://pub.ist.ac.at/~schloegl/matlab/NaN/
% This program is free software; you can redistribute it and/or modify
% it under the terms of the GNU General Public License as published by
% the Free Software Foundation; either version 2 of the License, or
% (at your option) any later version.
%
% This program is distributed in the hope that it will be useful,
% but WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
% GNU General Public License for more details.
%
% You should have received a copy of the GNU General Public License
% along with this program; If not, see <http://www.gnu.org/licenses/>.
if nargin==1,
m=0;s=1;
elseif nargin==2,
s=1;
end;
% allocate output memory and check size of argument
z = (x-m)./s; % if this line causes an error, input arguments do not fit.
%p = ((2*pi)^(-1/2))*exp(-z.^2/2)./s;
SQ2PI = 2.5066282746310005024157652848110;
p = exp(-z.^2/2)./(s*SQ2PI);
p((x==m) & (s==0)) = inf;
p(isinf(z)~=0) = 0;
p(isnan(x) | isnan(m) | isnan(s) | (s<0)) = nan;
%!assert(sum(isnan(normpdf([-inf,-2,-1,-.5,0,.5,1,2,3,inf,nan]',2,0))),1)
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