yf2num.m

JLAB is a set of Matlab functions I have written or co-written over the past fifteen years for the p

function[num]=yf2num(yf)
%YF2NUM  Convert date in 'year.fraction' format to 'datenum' format.
%
%   YF2NUM(YF) where YF is an array of dates in 'year.fraction' format
%   returns the array in Matlab's 'datenum' format.
%
%   See also NUM2YF, DATENUM, DATEVEC
%   __________________________________________________________________
%   This is part of JLAB --- type 'help jlab' for more information
%   (C) 2000, 2004 J.M. Lilly --- type 'help jlab_license' for details  
    
if strcmp(yf, '--t')
  yf2num_test,return
end

y=floor(yf);

%Number of days in this year?
d0=datenum(y-1,12,31);
d1=datenum(y,12,31);
nd=d1-d0;
num=d0+nd.*(yf-y)+1;

function[]=yf2num_test

yearf=[1850:(1/360):2004]';
num=yf2num(yearf);
yearf2=num2yf(num);
bool=maxmax(abs(yearf-yearf2))<1e-10;
reporttest('YF2NUM and NUM2YF, daily resolution, 1e-10 cutoff',bool)

yearf=[1990:(1/360/24):2004]';
%yearf=[1850:(1/360/24):2004]';
num=yf2num(yearf);
yearf2=num2yf(num);
bool=maxmax(abs(yearf-yearf2))<1e-10;
reporttest('YF2NUM and NUM2YF, hourly resolution, 1e-10 cutoff',bool)

%yearf=[1990:(1/360/24):2004]';
%yearf=[1850:(1/360/24):2004]';
%num2yearf(yf2num(1990))