8 replies to this topic

[debroy]

I want to develop a Program in C# that :

Find out all possible way to express a number(Suppose 42) with numbers from 1-9(not 0) and operators(+,-,*,/)(Operators can be used only once).
ex: 42 = 4 * 9 + 8 - 4/2 or 42 = 4*9 + 6 etc.

Can someone post any guide??

[WingedPanther]

Well, it doesn't have anything to do with Genetic Algorithms. I'd probably use a recursive algorithm.

[debroy]

That is not important. What I am wanting to know is how to write Genetic Algorithm in C#?

[debroy]

And Again How can I do it with Recursive Algorithm??

[WingedPanther]

To write a genetic algorithm, you first need a problem to solve where a genetic algorithm is appropriate. The details will vary somewhat, but you need an evaluation algorithm and a combination algorithm.

For recursive, I would have the algorithm process n-1 remaining items in an array, and the target value, with each of the operations and return a count of how many ways it can combine the new targets. (not sure if that makes sense)

[debroy]

Could u please explain it more?? And What type of problem should I need to solve with Genetic Algorithm

[anotheruser]

Do you realize that this problem has an infinite amount of solution?

for instance:
6 * 7 is a solution
each of the two factors can be split up like this:
(9 - 3) * (3+4)
as often as you want, creating an infinitely growing tree of possible solutions

You might be able to write a program that shows you all possible mathematical building-blocks to extend a given solution if you only allow natural numbers to be used.

You could also limit the degree how much mathematical functions may split, but I can't see how this would be possible otherwise.

[debroy]

Actually I am using Natural Nums 1-9.and Only + - * / these 4 operators can be used only once each. But the nums can repeat.

Ex : 11+ 31 = 42 is not applicable. And 40 + 1+1 = 42 is also Not Applicable;
but 6*6 + 6 = 42 is applicable;

anotheruser said:

Do you realize that this problem has an infinite amount of solution?

for instance:
6 * 7 is a solution
each of the two factors can be split up like this:
(9 - 3) * (3+4) -> This is N/A because after simplification it becomes 27 - 9 + 36 - 12 Here not only used Natural Nums > 9 but also two operator is used more than once.

I think you understand the Rules:
Rule1 = Only Natural Numbers 1-9 (!0) can be used and they can be used more than once
Rule2 = +,-,*,/ these 4 operators can be used and only once each. Brackets is N/A

as often as you want, creating an infinitely growing tree of possible solutions

You might be able to write a program that shows you all possible mathematical building-blocks to extend a given solution if you only allow natural numbers to be used.

You could also limit the degree how much mathematical functions may split, but I can't see how this would be possible otherwise.

So please give me some idea about Genetic Algo

Edited by Alexander, 25 October 2010 - 04:53 PM.
Merged three posts.

[WingedPanther]

If you are only using each operation once, nested for loops would make more sense, with the different orders as different loops. Why do you want genetic algorithms for this?

Note: a genetic algorithm should be selected as a solution when appropriate. It seems like you have a solution strategy in search of a problem, instead of the other way around.