[R] Huge number

[jim holtman]

If you want to compute (157+221)! then sum up the log:

> a <- 1:(157+221)
> sum(log10(a))
[1] 811.8165

This is about 6.55e811 which exceeds the range of floating point
numbers (1.797693e+308).  You might check out the Brobdingnag package.

On Feb 18, 2008 6:23 PM, Hyojin Lee <hyojinl at bcgsc.ca> wrote:
> Hi,
> I'm trying to calculate p-value to findout definitely expressed genes
> compare A to B situation.
> I got this data(this is a part of data) from whole organism , and each
> number means each expression values (that means, we could think 'a' gene
> is 13 in A situation, and it turns 30 in B situation)
> To findout probability, I'm going to use Audic - Claverie Method. ( The
> significance of digital gene expression profiles. 1997)
>
> But using this equation p(x|y), I have to calculate (x+y)!  first. but I
> can't  calculate (157+221)! or (666+1387)! in R.
> That's probabily the handling problem of huge number, How could I
> calculate p value in this data with R?
>
>
>                         A             B
> Total    5874641         6295980
> a        13      30
> b        36      39
> c        0       5
> d        40      61
> e        16      20
> f        13      11
> g        3       3
> h        9       5
> i        12      35
> j        157     221
> k        17      39
> l        6       17
> m        666     1387
> n        2       5
>
>
>
>
>
>
>
>
>
> The significance of digital gene expression profiles.
>
> Audic S
> <http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22A
> udic%20S%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_Result
> sPanel.Pubmed_RVAbstractPlusDrugs1> , Claverie JM
> <http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22C
> laverie%20JM%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_Re
> sultsPanel.Pubmed_RVAbstractPlusDrugs1> .
>
>        [[alternative HTML version deleted]]
>
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>



-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem you are trying to solve?