> Hi Martin,
>
> Here is my ztrans.input file in its current diabolical form - all the
> cleverness is yours and Themos's; the extra hack work is my own. It does
> forward transforms pretty well (of powers, exponential functions and
> mixtures thereof), but inverse transforms are less well handled. For
> example,
>
> ex:=ztrans(n^5,n,z)
>
> produces a formidable polynomial quotient; to invert it you need to apply
> partial fractions to ex/z, and apply the inverse transform to each
> individual fractional term multiplied by z. This is not happening right
> now.
>
> As well, I need to implement shifts:
>
> ztrans(f(n-k),n,z) == z^(-b)*ztrans(f(n),n,z)
>
> and for f(n+k).
>
Have you looked at laplace.spad.pamphlet? Computing Laplace transform
is related to computing ztransforms. In particular essentially all that
inverseLaplace currently do is to decompose rational function into
partial fractions and apply rule to each term separately.
--
Waldek Hebisch
[EMAIL PROTECTED]
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