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

Barton Willis willisb at unk.edu
Tue Aug 14 08:12:34 CDT 2007


-----maxima-bounces at math.utexas.edu wrote: -----

>Why doesn't erf(5) produce a numerical result, whereas
>sin(.3) or gamma(.2) do?

Because Maxima returns a floating point approximation to
most functions only when the function receives a floating
input or the option variable 'numer' is true; for example

(%i4) erf(5.0);
(%o4) 0.99999999999846

(%i5) numer : true$
(%i6) erf(5);

(%o6) 0.99999999999846
(%i7) numer : false$

(%i8) erf(5);
(%o8) erf(5)

>--------------------
>
>Can Maxima read a text file containing a column of
>numbers?
>

Yes, at a Maxima command line, try this

(%o2) ? read_matrix

Maxima should show you the user documentation for
'read_matrix' Maybe 'read_matrix' will do what you want.


>Is there a function to display available functions -
>not just those defined by a user?
>

Oh, not really. But if you can guess the function name, try entering
a question mark followed by your guess; for example

(%o3) ? erf

If you don't find what you are looking for and you are using wxMaxima,
you'll get a dialog box that will allow you to search the user
documentation.

Maybe this helps -- let us know if you have more questions.


Barton


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