phypers {DPQ}  R Documentation 
The Four (4) Symmetric 'phyper()' Calls
Description
Compute the four (4) symmetric phyper()
calls which
mathematically would be identical but in practice typically slightly
differ numerically.
Usage
phypers(m, n, k, q = .suppHyper(m, n, k), tol = sqrt(.Machine$double.eps))
Arguments
m 
the number of white balls in the urn. 
n 
the number of black balls in the urn. 
k 
the number of balls drawn from the urn, hence must be in

q 
vector of quantiles representing the number of white balls
drawn without replacement from an urn which contains both black and
white balls. By default all “nontrivial” abscissa values
i.e., for which the mathematical value is strictly inside 
tol 
a nonnegative number, the 
Value
a list
with components
q 
Description of 'comp1' 
phyp 
a numeric 
Author(s)
Martin Maechler
References
Johnson et al
See Also
R's phyper
. In package DPQmpfr,
phyperQ()
uses (package gmp based) exact
rational arithmetic, summing up dhyperQ()
, terms
computed by chooseZ()
, exact (long integer) arithmetic
binomial coefficients.
Examples
## The function is defined as
function(m,n,k, q = .suppHyper(m,n,k), tol = sqrt(.Machine$double.eps)) {
N < m+n
pm < cbind(ph = phyper(q, m, n , k), # 1 = orig.
p2 = phyper(q, k, Nk, m), # swap m <> k (keep N = m+n)
## "lower.tail = FALSE" <==> 1  p..(..)
Ip2= phyper(m1q, Nk, k, m, lower.tail=FALSE),
Ip1= phyper(k1q, n, m, k, lower.tail=FALSE))
## check that all are (approximately) the same :
stopifnot(all.equal(pm[,1], pm[,2], tolerance=tol),
all.equal(pm[,2], pm[,3], tolerance=tol),
all.equal(pm[,3], pm[,4], tolerance=tol))
list(q = q, phyp = pm)
}
str(phs < phypers(20, 47, 31))
with(phs, cbind(q, phyp))
with(phs,
matplot(q, phyp, type = "b"), main = "phypers(20, 47, 31)")
## differences:
with(phs, phyp[,1]  phyp[,1])
## *relative*
relE < with(phs, { phM < rowMeans(phyp); 1  phyp/phM })
print.table(cbind(q = phs$q, relE / .Machine$double.eps), zero.print = ".")