Use of erf(x); read text file; command to display available functions

Hi Charles!

It seems you are regularly asking questions on the maxima ML. Perhaps
you should consider subscribing to this ML. This would have the
advantage, that you get faster replies because you don't need to
wait until one of the list moderators approves your message.

> Is there a function that returns the size of a matrix: for example, if
> M is a matrix of dimension nxm, the function size(M) would return the
> list [n,m]? Such a function does not appear in the reference manual
> matrix chapter.

m:matrix([x,y,z],[a,b,c]);
[length(m),length(m[1])]; -> [2, 3]

> Apparently, plot2d will not plot a matrix that is 1xn or mx1; it only
> plots lists (or functions). So, to plot a matrix, for example
> columnwise, it is necessary to write a separate function to pick off
> the columns, convert them to lists, and plot one-by-one. Am I missing
> something? 

Yes, lambda expressions.

> It would be good to make plotting work with any data type in
> Maxima. 

I don't think there is a canonical meaning of plotting a matrix.
I'm not sure what you are proposing.

> That avoids writing special functions for conversions and makes
> use of the tool more uniform.

Actually maxima is very uniform because it is a functional programming
language where you can write conversions on the fly easily.


HTH,
Harald

P.S.: If I've totally misunderstood your proposal, perhaps you should
explain it by suggesting an actual algorithm. Right now you mail
somewhat reads like "It should do what I want.", which leaves lots of
space for interpretation.