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## Re: [*] Re: [Help-gsl] Approximate Comparison of Floating Point Numbers

**From**: |
Awhan Patnaik |

**Subject**: |
Re: [*] Re: [Help-gsl] Approximate Comparison of Floating Point Numbers |

**Date**: |
Thu, 18 Jun 2009 11:28:51 +0530 |

On Fri, Jun 5, 2009 at 7:14 PM, Brian Gough <address@hidden> wrote:
>* At Tue, 2 Jun 2009 13:34:39 +0530,*
>* Awhan Patnaik wrote:*
>* >*
>* > With reference to int gsl_fcmp (double x, double y, double*
>* > epsilon) is there a default choice of epsilon that will work for*
>* > ``almost" all situations ?*
>
>
>* I think this really depends on the context, there is a discussion in*
>* Knuth which is the starting point and is worth checking out.*
>
According to the definition of DBL_EPSILON
"Difference between 1 and the least value greater than 1 that is
representable. ". I was hoping that this would be a generic choice of
epsilon that would allow any computer to resolve between two floating point
numbers.
I have a code where I have to compare a lot of floating point numbers. In
most of the previous cases the ranges were in the > 1.0 range but I soon
ran into a situation where I had to compare numbers of the order 1e-6 and
there I began to worry about the accuracy of my code.
Is there a way in which one can choose a context independent epsilon ?
-awhan