Hi All,
I am using the function fractions() and cognates from MASS. I would
like to be able to tell if some calculations I am doing on some
rationals are transformed into floats and then retransformed into
rationals.
For instance I suspect that
as.fractions(1/8) + as.fractions(1/4)
does transform into floats and back, while I know
1/as.fractions(8) + 1/as.fractions(4)
does not. Since I am using sum() and doing a number of
multiplications I would like to know so I can intervene.
For instance, what's happening here?
> pun
[,1] [,2]
[1,] 1 1
[2,] 4 4
> library(MASS)
> pun[1,]/as.fractions(pun[2,])
[1] 1/4 1/4
> sum(pun[1,]/as.fractions(pun[2,]))
[1] 1/2
Best,
Federico
--
Federico C. F. Calboli
Department of Epidemiology and Public Health
Imperial College, St. Mary's Campus
Norfolk Place, London W2 1PG
Tel +44 (0)20 75941602 Fax +44 (0)20 75943193
f.calboli [.a.t] imperial.ac.uk
f.calboli [.a.t] gmail.com