Re: what is the use of "u" in tabulated output?

[sfeam <sf...@us...>]

On Wednesday, 23 April 2014 09:06:15 PM pl...@pi... wrote:
> On 04/23/14 20:47, Ethan A Merritt wrote:
> >
> > On Sunday, 20 April, 2014 10:48:10 pl...@pi... wrote:
> >>    HI,
> >>
> >>
> >> I often use conditional using clauses to plot part of a range of data
> >>
> >> plot datafile using   (($1<=1995.55)?$1:NaN):(2*fcos1($1))
> >>
> >> I tried this when writing to a file specified with "set table"  and
> >> instead of cutting off the output, it appends garbage data with a "u".
> >>
> >> help table tells me this means "undefined"
> >>
> >> I see two problems here. I did not ask for undefined output , I
> >> specified NaN.
> >>
> >> Secondly , what is the possible use of "undefined" values in a data file?
> >>
> >> 1995.46  1.00914  i
> >> 1995.54  1.10947  i
> >> 1.98547e-81  4.74363e+170  u
> >> 3.75845e+174  7.52884e-24  u
> >> 0  2.122e-314  u
> >> 0  0  u
> >> 0  0  u
> >> 1.9771e+161  1.44402e+214  u
> >> -1.22337e-44  1.1735e-319  u
> >> 1.01887e+189  7.49746e+247  u
> >> 5.35166e+199  2.10124e+88  u
> >
> > I do not know what the original idea was,
> > nor do I know if there are existing scripts that depend on the 'u'.
> > It does seem pointless to write out total junk values as in your example.
> >
> > If it helps, version 5 has a new mode "with table" that does what you want.

As of yesterday, the version 5 code has been changed to store the actual input
values even if some value on the line is NaN, causing the whole line to be
marked "undefined".  Since the values are stored, they are available for 
output in a table.  Also they are available to be used in a "refresh" command.

I can't think of anything this would break, but it is definitely a change
in the version 4 behavior.

	Ethan