[Octave-bug-tracker] [bug #43753] datevec returns negative dates with integer datenum

[Avinoam Kalma]

Follow-up Comment #2, bug #43753 (project octave):

Hi,

Maybe a better solution is to use another variable for double(date):


    date0 = double(date);
    date0 = date0(:);

    ## Move day 0 from midnight -0001-12-31 to midnight 0000-3-1
    z = floor (date0) - 60;
    ## Calculate number of centuries; K1 = 0.25 is to avoid rounding
problems.
    a = floor ((z - 0.25) / 36524.25);
    ## Days within century; K2 = 0.25 is to avoid rounding problems.
    b = z - 0.25 + a - floor (a / 4);
    ## Calculate the year (year starts on March 1).
    y = floor (b / 365.25);
    ## Calculate day in year.
    c = fix (b - floor (365.25 * y)) + 1;
    ## Calculate month in year.
    m = fix ((5 * c + 456) / 153);
    d = c - fix ((153 * m - 457) / 5);
    ## Move to Jan 1 as start of year.
    ++y(m > 12);
    m(m > 12) -= 12;

    ## Convert hour-minute-seconds.  Attempt to account for precision of
    ## datenum format.

    fracd = date0 - floor (date0);
    tmps = abs (eps*86400*date0);


Avinoam

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