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Topic: Help with creating a function
Replies: 12   Last Post: Nov 19, 2013 3:48 AM

 Messages: [ Previous | Next ]
 quasi Posts: 12,067 Registered: 7/15/05
Re: Help with creating a function
Posted: Nov 18, 2013 6:57 AM

quasi wrote:
>Robert Crandal wrote:
>>
>>Suppose I have the following X-Y data set:
>>
>>X Y
>>-- --
>>0 1
>>1 1
>>2 2
>>3 3
>>. .
>>. .
>>N N
>>
>>Can this be represented with a math function?
>>
>>(Only consider positive integers >= 0)

>
>It's already a function since for each x in the domain, there
>is a unique y.
>
>Presumably you want a "formula".
>
>The function f defined on the set of nonnegative integers
>by the formula
>
> f(x) = ((x-1)*(((2*x-1)/abs(2*x-1))+1)/2)+1
>
>is not pretty but it works.

Here's a simple one based on the floor function.

f(x) = x + floor(1/(x+1))

quasi

Date Subject Author
11/18/13 Robert Crandal
11/18/13 quasi
11/18/13 Robert Crandal
11/18/13 quasi
11/18/13 David Hartley
11/18/13 quasi
11/18/13 Roland Franzius
11/18/13 quasi
11/18/13 quasi
11/19/13 quasi
11/18/13 Richard Tobin
11/18/13 Stuart M Newberger
11/18/13 Peter Percival