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## #1 2014-03-03 17:16:14

Agnishom
Real Member
From: Riemann Sphere
Registered: 2011-01-29
Posts: 23,761
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### Optimising Ackermann Recursions

How can I have a method that calculates Ackermann Functions very fast?

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.

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## #2 2014-03-04 05:10:02

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 104,196

### Re: Optimising Ackermann Recursions

Hi;

It would be extremely fast because the numbers grow very large, very quickly, so even with M you could only compute the first few.

For instance:

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
A number by itself is useful, but it is far more useful to know how accurate or certain that number is.

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## #3 2014-03-04 15:02:03

Agnishom
Real Member
From: Riemann Sphere
Registered: 2011-01-29
Posts: 23,761
Website

### Re: Optimising Ackermann Recursions

Suppose I am interested in the last 4 digits of A(4,4)?

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.

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## #4 2014-03-04 16:13:50

anonimnystefy
Real Member
From: Harlan's World
Registered: 2011-05-23
Posts: 16,015

### Re: Optimising Ackermann Recursions

Then I'd either find a very fast and powerful computer or do a lot of number theory.

Here lies the reader who will never open this book. He is forever dead.
Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

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## #5 2014-03-04 16:14:52

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 104,196

### Re: Optimising Ackermann Recursions

You can probably get the last 4 digits.

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
A number by itself is useful, but it is far more useful to know how accurate or certain that number is.

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