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**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,673

I did use my function:

Input:

```
list : [6,6,6,6]$
expand(CombOGF(list)/6^4);
```

Output:

```
x^24/1296+x^23/324+(5*x^22)/648+(5*x^21)/324+(35*x^20)/1296+(7*x^19)/162+(7*x^18)/108+(29*x^17)/324+(149*x^16)/1296+(5*x^15)/36+(103*x^14)/648+(14*x^13)/81+(77*x^12)/432+(14*x^11)/81+
(103*x^10)/648+(5*x^9)/36+(149*x^8)/1296+(29*x^7)/324+(7*x^6)/108+(7*x^5)/162+(35*x^4)/1296+(5*x^3)/324+(5*x^2)/648+x/324+1/1296
```

And the term with exponent 20 has the coefficient of 35/1296.

*Last edited by anonimnystefy (2012-04-30 08:00:36)*

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**bobbym****Administrator**- From: Bumpkinland
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Now supposing 2 die had faces of 2,4,6,8,10,12 and 2 other die had faces of 1,3,5,7,9,11.

All four die are thrown once. What is the probability of them summing to 20 or more?

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**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
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493/648?

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
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That is not correct.

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**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

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**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
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Thought so.

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
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What did you have a problem with?

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**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
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Altering the code to acompany the numbers on the dice.

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**bobbym****Administrator**- From: Bumpkinland
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There is a rather succinct method to do that in mathematics. It is called

summation notation. It is perfect. It is implemented in Maxima. That is why I suggested you use

math commands to do math tasks.

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**anonimnystefy****Real Member**- From: The Foundation
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I did use the summation un a part of my code.

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**bobbym****Administrator**- From: Bumpkinland
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But you did not use parameters with the summation. Then the code is simple, fast and

complete.

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**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
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Iwill try today you function. But I do not like that I have to type everything agin to make a GF for more dice.Here for 100 dice,I could just make code (agin to your disliking) to make me a list of 100 omes. I just put that list into my function and I am done.

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**bobbym****Administrator**- From: Bumpkinland
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You are misunderstanding my reasoning. It is not an arbitrary decision. It is not bobbym's

function.

1) Built in functions are faster and use less memory than procedural code.

2) Your function can not handle gf's that increment by more than one. Remember yours

did not get the right answer.

3) Supposing you were throwing 10 million die? Do you want to create a list of

10 million numbers? My function does not grow in size when the problem does

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**anonimnystefy****Real Member**- From: The Foundation
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The first one is right.

The second one is not correct. I made a new one that uses the parameter n for the increment.

Third one is also right.

4)Is yyour function applicable to dice with more sides?

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**bobbym****Administrator**- From: Bumpkinland
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Of course!

About 2) Your new function is probably larger, uses more memory and is slightly slower.

In mine it easy to do things like that with no overhead increase. Bet it took you a couple of hours to

add your addition. In mine additions are part of the notation.

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**anonimnystefy****Real Member**- From: The Foundation
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Nope,just one multiplication by n.

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**bobbym****Administrator**- From: Bumpkinland
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But I hope you can see that the one I want you to use is smaller.

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**anonimnystefy****Real Member**- From: The Foundation
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Yes,I will try your way.

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**bobbym****Administrator**- From: Bumpkinland
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Is there something done?

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**anonimnystefy****Real Member**- From: The Foundation
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Not yet. No access to Maxima yet.

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**anonimnystefy****Real Member**- From: The Foundation
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Hi bobbym

Check out this link:A pdf file on GFs in counting problems

It isn't very much,but does explain some crucial things.

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**bobbym****Administrator**- From: Bumpkinland
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Hi anonimnystefy;

I disagree it is quite good.

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**anonimnystefy****Real Member**- From: The Foundation
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Who said it wasn't good. Everything that you need is in there. Maybe a few more solved harder examples and it would be even better.

Hay,I found somewhere a GF for partitions of a number but I disagree with the formula. Could you post the partition GF you think is right?

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**bobbym****Administrator**- From: Bumpkinland
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Depends on what you are partitioning.

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**anonimnystefy****Real Member**- From: The Foundation
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Partitions of a number.

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**bobbym****Administrator**- From: Bumpkinland
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Which numbers?

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