How Can I Use plot2d code for presence of singularities?

cute, using compiler type inference.not exactly easy to access.


There are interval packages that might be easier to use.  I have probably
3 myself, of varying sophistication, written in Common Lisp.
One, in the generic package, even has some code for Maxima to implement
interval evaluation.  (see 
http://www.cs.berkeley.edu/~fateman/lisp/generic )
RJF


On 12/24/2012 5:04 PM, Raymond Toy wrote:
>>>>>> "Richard" == Richard Fateman <fateman at eecs.berkeley.edu> writes:
>      Richard> How about evaluating the expression in interval arithmetic and seeing
>      Richard> if it is bounded or not.
>      Richard> If it is unbounded, bisect the range.  Etc.
>
> That would probably work.  I don't have any interval package for
> maxima, but you can get an idea with cmucl and sbcl:
>
> to_lisp();
> (defun foo (x)
>    (declare (type (double-float 0.0d0 1d0)) x)
>    (values (/ x (expt (- 1/2 x) 3)) (expt (- 1/2 x) 3)))
>
> (compile 'foo)
> (describe 'foo) ->
>
> Function arguments:
>    (x)
> Its defined argument types are:
>    ((DOUBLE-FLOAT 0.0d0 1.0d0))
> Its result type is:
>    (VALUES DOUBLE-FLOAT (DOUBLE-FLOAT -0.125d0 0.125d0))
>
> So, indeed, the first expression is unbounded (plain double-float
> means unbounded), and we can see that (1/2-x)^3 contains 0 because the
> interval is -1/8 to 1/8.
>
> Ray
>
>
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