[Maxima-discuss] weird behavior of apply

[Dimiter P. <dim...@gm...>]

Hello,

I define a function

dy(y):=if y#0 and y#0.0 then  1/(2*y)   else 'nan;

Then I wanted to substitute it's first argument by a value. The idea is to
use pass a function having a variable number of arguments as a method
parameter and then to evaluate it only on certain arguments.


I stumbled on the following weird behavior:

apply(dy, [y=0]);
expt: undefined: 0 to a negative exponent.
 -- an error.

also here

at(dy(y),[y=0]);

expt: undefined: 0 to a negative exponent.
 -- an error.

while  dy(0) correctly evaluates to 'nan

best regards,

Dimiter