C,D labels



--- James Frye <frye@cs.unr.edu> wrote:

> Both.  It's all pretty non-obvious to me, starting with the use of C
> and D as input & output labels :-)  I can see the point of getting 
> previous input to edit, in case I make a mistake or want to make
minor
> changes, but IMHO that's much easier to do with the normal command 
> recovery - just hit the up-arrow key a few times.

Right, but IIRC when Maxima was originally written computers didn't
have that ability.

> As for the outputs, maybe this is just my ignorance showing, but it
> seems that maxima seldom if ever returns results in a form that could

> be used directly in another expression, or easily edited.

Um.  You mean things like diff(D2,x); don't work for you?

> > Another useful thing about saving the inputs is that Maxima can
> > pretty-print them for you, which helps in finding errors sometimes,
> > or simply in showing them to others.  Unfortunately, Maxima's
> > pretty-printer could be better, but....
> 
> How?  I've tried doing TEX (expression), and then feeding the result
> into Latex, but it seldom works.  Don't know if it's me, or what.

You might try using the emaxima package - it is what I am using to
write the Maxmia Book.  That so far has worked surprisingly well.

> > In other words, I don't know in advance which results will be
> > useful and which will not -- most *might* be useful, and even if I 
> > abandon one line of work temporarily, I may go back to it later.  
> > Even in the days when Maxima ran in 1 MB of memory, we found it 
> > useful to save results. Nowadays, with basically unlimited memory,
I 
> > see no reason at all to throw away results.

I agree.  The question is whether or not there is a better way than C
and D labels.  Actually, the ability to change inchar and outchar
raises  an important programming principle we should put down,
particularly for the share packages.  When programming, do not program
in such a way that the correct behavior of the program depends on the
value of inchar or outchar being C, D, or any particular value.

There's a principle we can add to the "ANSI Common Lisp" principle Jim
:-).
 
> Which is one reason I've been doing the edit file, then batch thing.
> Plain Maxima doesn't seem to have any way to save interaction in a
> readable format, and xmaxima doesn't seem to have working
> command-line editing & recovery, so what I wind up doing is using 
> plain Maxima with batch, and possibly some interactive modification
to 
> experiment.  Then when I have a final result I'm satisfied with, I 
> re-run the batch file in xmaxima, save the output to a file, which I 
> then edit & print. 

Um.  I believe there are commands in maxima to write all inputs and
outputs to a file.  Would that do what you want?

You might also want to explore emaxima a bit - I've found it quite
useful.

> > I do STRONGLY believe we can improve on Maxima's interaction
> > paradigm -- something better than both C1/D1 and workbooks -- but I

> > am still working on that....  

I would be very curious to see any such advances.

CY

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