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Polygamma function in cycle

ptc-4871036
1-Newbie

Polygamma function in cycle

Good day,

I have a problem with the psi(1,y) function.

y_i are the Maxwell random variables, which I generate.

Program is attached.

I would be happy for your answers.

6 REPLIES 6
StuartBruff
23-Emerald III
(To:ptc-4871036)

The Psi function only takes one parameter; try just Psi(y).

Stuart

Stuart,

The digamma function, Psi(x), is defined to be the derivative of the natural logarithm of the Gamma function Γ(x).

The polygamma function, Psi(k, x), is defined to be the kth derivative of the Gamma function.

Pic_1.PNG

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StuartBruff
23-Emerald III
(To:VladimirN)

That will teach me to read the documentation instead of just looking at the error message (... well, it won't. Unfortunately, I have never been possessed of 100 % hindsight and am perfectly capable of replicating the same error )

Stuart

That's ok.

RichardJ
19-Tanzanite
(To:ptc-4871036)

Mathcad has two processors: one for symbolic math, and one for numeric math. The Psi function is only defined for symbolic math. That's easily remedied though.

U saved me!

That was really easy, this was my first idea but without vectorization...and it didn't work...

Thx a lot one more time

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