Factorial function?

Is there a factorial function in VB? I found a factorial Grasshopper component, but I'd like to write an equation using factorials, as opposed to forming the equation from components.

I want to calculate n choose k, as seen in below image.

Replies to This Discussion

Permalink Reply by jon kontuly on January 27, 2010 at 8:32pm

Do you mean this?

Attachments:

factorial[autosave].gh, 4 KB

Permalink Reply by Chris Wilkins on January 27, 2010 at 8:36pm

I tried that, but I need (0!) to be defined as 1. It is turning up null using that expression.

Permalink Reply by Chris Wilkins on January 27, 2010 at 8:33pm

Here's the component version:

Permalink Reply by jon kontuly on January 27, 2010 at 8:54pm

could you just insert a vb component in between n-k and (n-k)! that checks if its 0 and if so sets it to 1

Attachments:

factorial[autosave].gh, 6 KB

Permalink Reply by Chris Wilkins on January 28, 2010 at 4:37am

No. That way will calculate n=0 or n=k to be equal to the same result as n=1 or n=k-1, but n=0 and n=k should evaluate to 1. See above example.

I'm sure it's easy to write a VB function to do it, but I was just hoping there was one already.

thx

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