Re: 30-year time offset reading nonuniform matrix %s input

[Ethan M. <merritt@u.washington.edu>]

On Thursday, April 04, 2013 08:08:08 am Petr Mikulik wrote:
> Tait wrote:
> >> In the first case, the year is correctly set to 2013. In the second,
> >> it is displayed as 2043. This seems to be a mistake in the nonuniform
> >> matrix time input?
> 
> Ethan wrote:
> > This probably fixes it, but the possible consequences elsewhere are not
> > certain.  At a minimum it makes all references to the year 2000 in the
> > manual incorrect, since it resets the epoch boundary to 1970.

Petr wrote:
> What about adding
>  	set datafile epoch 2000
> so that the year can be set by the user?

The epoch affects time calculation throughout the program, so tying 
it to "set datafile" would be misleading.  For example
gnuplot> print time(0)
prints number of seconds since the epoch boundary without any 
data file being accessed.

Or did you mean that we should add a per-datafile option that
would temporarily override the program's default epoch only 
for the purpose of reading that one file?  That would be
possible, but I am not sure that it solves any real-world problem.
If the data file contains time represented as a number of raw seconds,
which is I think the only case this would affect, then you can
already read it in as a plain number and convert to time/date using 
whatever epoch adjustment you like.  Right?  Or maybe not? I don't
normally use the time format routines so I am kind of hazy on what
they can or can't do.

I'd still like to know what the origianl rationale was for 
choosing 2000 rather than 1970.  I know plenty of problems that
this choice caused, but what problems did it solve?
Are they still relevant?

	Ethan

-- 
Ethan A Merritt
Biomolecular Structure Center,  K-428 Health Sciences Bldg
University of Washington, Seattle 98195-7742