Conversion Utilities gmp <-> Rmpfr
.bigz2mpfr(x, precB = NULL, rnd.mode = c('N','D','U','Z','A'))
.bigq2mpfr(x, precB = NULL, rnd.mode = c('N','D','U','Z','A'))
.mpfr2bigz(x, mod = NA)x |
an R object of class |
precB |
precision in bits for the result. The default,
|
rnd.mode |
a 1-letter string specifying how rounding
should happen at C-level conversion to MPFR, see details of
|
mod |
a possible modulus, see |
Note that we also provide the natural (S4) coercions,
as(x, "mpfr") for x inheriting from class "bigz"
or "bigq".
a numeric vector of the same length as x, of the desired class.
S <- gmp::Stirling2(50,10)
show(S)
SS <- S * as.bigz(1:3)^128
stopifnot(all.equal(log2(SS[2]) - log2(S), 128, tolerance=1e-15),
identical(SS, .mpfr2bigz(.bigz2mpfr(SS))))
.bigz2mpfr(S) # 148 bit precision
.bigz2mpfr(S, precB=256) # 256 bit
## rational --> mpfr:
sq <- SS / as.bigz(2)^100
MP <- as(sq, "mpfr")
stopifnot(identical(MP, .bigq2mpfr(sq)),
SS == MP * as(2, "mpfr")^100)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.