Fast functions for dealing with prime numbers, such as testing
whether a number is prime and generating a sequence prime numbers.
Additional functions include finding prime factors and Ruth-Aaron pairs,
finding next and previous prime numbers in the series, finding or estimating
the nth prime, estimating the number of primes less than or equal to an
arbitrary number, computing primorials, prime k-tuples (e.g., twin primes),
finding the greatest common divisor and smallest (least) common multiple,
testing whether two numbers are coprime, and computing Euler's totient
function. Most functions are vectorized for speed and convenience.

S original by Trevor Hastie <trevor@research.att.com>
R port by Andreas Weingessel <Andreas.Weingessel@ci.tuwien.ac.at>
fits a principal curve to a data matrix in arbitrary
dimensions

Fits a Principal Curve in Arbitrary Dimension

S original by Trevor Hastie <trevor@research.att.com> R port by
Andreas Weingessel <Andreas.Weingessel@ci.tuwien.ac.at>

c(
person("Trevor", "Hastie", email = "trevor@research.att.com", role = "aut"),
person("Andreas", "Weingessel", email = "Andreas.Weingessel@ci.tuwien.ac.at", role = "aut"),
person("Kurt", "Hornik", email = "kurt.hornik@wu.ac.at", role = "aut"),
person("Robrecht", "Cannoodt", email = "rcannood@gmail.com", role = c("aut", "cre")))
Fitting a principal curve to a data matrix in arbitrary dimensions.
Trevor Hastie [aut],
Andreas Weingessel [aut],
Kurt Hornik [aut],
Robrecht Cannoodt [aut, cre]

c(
person("Trevor", "Hastie", email = "trevor@research.att.com", role = "aut"),
person("Andreas", "Weingessel", email = "Andreas.Weingessel@ci.tuwien.ac.at", role = "aut"),
person("Kurt", "Hornik", email = "kurt.hornik@wu.ac.at", role = "aut"),
person(
"Robrecht",
"Cannoodt",
email = "rcannood@gmail.com",
role = c("aut", "cre"),
comment = c(ORCID = "0000-0003-3641-729X", github = "rcannood")
))
Trevor Hastie [aut],
Andreas Weingessel [aut],
Kurt Hornik [aut],
Robrecht Cannoodt [aut, cre] (<https://orcid.org/0000-0003-3641-729X>,
rcannood)