R help - Feb 2010 - machine precision problem

Dear all,

I am analysising a set of gene expression data using multiplicative Gaussian
Kernel function. I calculated the kernels between two gene sets with 20000
genes for each set. The kernels are less than 1, therefore the product of
the kernels is out of the minimum precision in R. I wonder if there is a way
to lowering the minimum double precision in R. I am using R version 2.10.1. 

Thank you in advance.
Wendy 
-- 
View this message in context:
http://n4.nabble.com/machine-precision-problem-tp1563732p1563732.html
Sent from the R help mailing list archive at Nabble.com.

On Feb 21, 2010, at 1:37 PM, wendy wrote:
>
> Dear all,
>
> I am analysising a set of gene expression data using multiplicative  
> Gaussian
> Kernel function. I calculated the kernels between two gene sets with  
> 20000
> genes for each set. The kernels are less than 1, therefore the  
> product of
> the kernels is out of the minimum precision in R. I wonder if there  
> is a way
> to lowering the minimum double precision in R. I am using R version  
> 2.10.1.
>
Have you considered other strategies, e.g. summing the logs and  
exponentiating?

Your proposed solution would involve rewriting R. There is no switch  
to throw that would increase the width of doubles.

-- 
David