Re: multiple plot lines with plot '-'

[Allin C. <cot...@wf...>]

On Wed, 16 May 2012, Ethan A Merritt wrote:

> On Wednesday, May 16, 2012 01:17:22 pm Allin Cottrell wrote:
>
>>>> Just a notion, but what if gnuplot's syntax permitted defining a matrix
>>>> (either "inline" with some nice, simple syntax or by reading from a
>>>> file), and you could then say something like
>>>>
>>>> plot matrix "foo" using ...
>>>>
>>>> as many times as you wanted, using whichever columns?
>>
>> The way I'm thinking about this, no look-ahead is needed. All
>> gnuplot has to do is store the given matrix (all of it), then draw
>> on it as and when specified.
>
> There is a significant subset of gnuplot users for whom it is a key
> feature that gnuplot can handle large data sets.  Here "large"
> means millions of points.  It can do this exactly because it does
> not store the entire contents of the data file prior to processing.

Fine, understood. But that need not rule out the possibility of 
storing a reasonably sized matrix to serve as the target for 
repeated plot commands, for those who want to do that sort of thing.

>> I'm mooting this as an extension of the way that gnuplot can
>> currently store scalars (and complex numbers) for future use,
>> without having any idea at the time what they'll be used for.
>
> Sorry, you lost me there.  What are you refering to?

Nothing mysterious, just

d = 1.3257
c = {1.5, 3.1}

and so on. I'm envisaging, say,

m = {1,2,3; 4,5,6; 7,8,9}

where (just for illustration) I'm assuming a matrix syntax in which 
',' is the column separator and ';' is the row separator.

> It's been suggested before.  For example, Feature Request #1957568
> https://sourceforge.net/tracker/index.php?func=detail&aid=1957568&group_id=2055&atid=352055

OK, I see what you mean, but please note that I'm _not_ requesting
that "calculations can be done with the [matrix] data". That, it 
seems to me, is not gnuplot's job.

> I'd like to see a more fully-developed proposal before seriously
> considering it.

Or a patch; I'm not just requesting that someone else does this for 
me.

> You can bet that the moment we provided a way to read in a matrix, 
> people would start clamoring for math library support to do matrix 
> operations.

FWIW you'd have my full support in resisting that sort of bloat. All 
I'm interested in is a more efficient way to "inline" plottable data 
in a gnuplot command file.

Allin Cottrell