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I defined my own AltGamma[z], how to stop 'matica using its Gamma[z] rules?

Posted 10 years ago

I've defined an entire Gamma function. It does not match the negative axis of the Euler Gamma[z], and so the transforms of the Gamma built in are not appropriate. How do I disable the built in rules for Gamma[z], so that I can actually do maths using my functional definition?

POSTED BY: Simon Jackson
3 Replies

I suggest you call your function myGamma and use it that way. The built-in function might be used for other calculations.

POSTED BY: Frank Kampas

You don't want to redefine Gamma. Changing it might break anything built on top of it. Having warned about that, you can change Gamma with the Unprotect and Protect expressions. For example:

Unprotect[Gamma]
Gamma[x_] := x*2
Protect[Gamma]

Frank Kampas's suggestion is the correct one.

POSTED BY: Sean Clarke
Posted 10 years ago

Thanks for the info. I do actually want to redefine gamma. I know this may break things in a particular notebook, but the purpose of the notebook is to use this alternate gamma. I think the functional equation is different, and so I would want to remove all transform rules to a un gamma ed state. This includes cutting back all function rules which use it. I realize this may break things in some way, in this particular notebook, this full elimination is what is required.

Gamma[z_] := Cgamma Exp[Sum[1/(n+1) Sum[(-1)^(k+1) Binomial[n, k] Log[k+z], {k, 0, n}], {n, 0, Infinity}]]

The aim being to deduce replacement functionality based on this definition of Gamma. The research being about this alternate gamma, needs any conflict of definition removed.

EDIT: an alternate method maybe to wrap reals so that no gamma operation is performed on the ungammaed reals, apart from the ones I define, such that Gamma is still available if need be. Any info on how to do this?

EDIT2: I am getting distracted by the FIASCO codec in the Netpbm library.

POSTED BY: Simon Jackson
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