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precision of double in R
2 messages · Burkhard Heil, Duncan Murdoch
On 11/11/2005 9:55 AM, Burkhard Heil wrote:
Hello Everybody! I'm working on biological sequences and their alignements. I can't get around calculating something in the size of choose(1000,500) or 0.02^250. The result is either INF or 0 in the latter case. Is their any data type in R to calculate these things. Or some other solution?
Use logs. log(0.02^250) is easy to calculate as 250*log(0.02). There's also an lchoose() function; it gives > lchoose( 1000, 500) [1] 689.4673 without complaining. Duncan Murdoch