dastew at sympatico.ca
Sat Feb 14 13:15:13 CST 2009
Robert Dodier wrote:
> On 2/14/09, Doug Stewart <dastew at sympatico.ca> wrote:
>> I see some work was done on Z Transforms in 2007, but I can't find it now.
>> I am using Maxima 5.13.0 in Ubuntu.
>> How do I get it to work?
> I recently worked on the z-transform stuff again and made some progress.
> I've committed the z_transform.mac program and rtest_z_transform.mac
> test script. You should be able to see them here:
> They will be in the next release (due in April).
> random example:
> load (z_transform);
> apply_z_transform (z_transform (1 + kron_delta (m, x), m, u));
> => 1/u^x+u/(u-1)
> batch (rtest_z_transform, test);
> => (... lots o' stuff ...) 24/24 tests passed.
> Hope this helps. I';ll be glad to hear any comments. There are
> doubtless many more transform rules that can be implemented,
> maybe we can get going on that. By the way, I'll recommend
> getting the most recent version of Maxima (5.17.1).
> Robert Dodier
Thank You !!!!
here is one example that needs a little polish :-)
with the "-" in the exponential it doesn't work
(%i77) apply_z_transform (z_transform (a+b*(e^(-p*T))^(m) , m, z));
a z 1
----- + b z_transform(-------, m, z)
z - 1 p T m
But without the "-" it works.
(%i76) apply_z_transform (z_transform (a+b*(e^(p*T))^(m) , m, z));
b z a z
-------- + -----
p T z - 1
z - e
A happy Doug
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