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View of /pkg/inlinedocs/inst/testfiles/fermatExAttr.R

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Revision 140 - (download) (annotate)
Tue Oct 19 23:24:01 2010 UTC (7 years ago) by tdhock
File size: 4295 byte(s)
do ex in tempdir
fermat.test <- function#Test an integer for primality with Fermat's little theorem.
### Fermat's little theorem states that if \eqn{n} is a prime number
### and \eqn{a} is any positive integer less than \eqn{n}, then
### \eqn{a} raised to the \eqn{n}th power is congruent to \eqn{a\
### modulo\ n}{a modulo n}.
##references<< \url{http://en.wikipedia.org/wiki/Fermat's_little_theorem}
(n ##<< the integer to test for primality.
 ){
  a <- floor(runif(1,min=1,max=n))
  ##note<< \code{fermat.test} doesn't work for integers above
  ##approximately 15 because modulus loses precision.
  a^n %% n == a
### Whether the integer passes the Fermat test for a randomized
### \eqn{0<a<n}
}
is.pseudoprime <- structure(function
### A number is pseudo-prime if it is probably prime, the basis of
### which is the probabalistic Fermat test; if it passes two such
### tests, the chances are better than 3 out of 4 that \eqn{n} is
### prime.
##references<< Abelson, Hal; Jerry Sussman, and Julie
##Sussman. Structure and Interpretation of Computer
##Programs. Cambridge: MIT Press, 1984.
(n, ##<< the integer to test for pseudoprimality.
 times ##<< the number of Fermat tests to perform
){
  if(times==0)TRUE
  ##seealso<< \code{\link{fermat.test}}
  else if(fermat.test(n)) is.pseudoprime(n,times-1)
  else FALSE
### Whether the number is pseudoprime.
},ex=function(){
  is.pseudoprime(13,4)
})

.result <- 
 list(fermat.test = list(format="",definition = "fermat.test <- function#Test an integer for primality with Fermat's little theorem.\n### Fermat's little theorem states that if \\eqn{n} is a prime number\n### and \\eqn{a} is any positive integer less than \\eqn{n}, then\n### \\eqn{a} raised to the \\eqn{n}th power is congruent to \\eqn{a\\\n### modulo\\ n}{a modulo n}.\n##references<< \\url{http://en.wikipedia.org/wiki/Fermat's_little_theorem}\n(n ##<< the integer to test for primality.\n ){\n  a <- floor(runif(1,min=1,max=n))\n  ##note<< \\code{fermat.test} doesn't work for integers above\n  ##approximately 15 because modulus loses precision.\n  a^n %% n == a\n### Whether the integer passes the Fermat test for a randomized\n### \\eqn{0<a<n}\n}",  
     title = "Test an integer for primality with Fermat's little theorem.",  
     description = "Fermat's little theorem states that if \\eqn{n} is a prime number\nand \\eqn{a} is any positive integer less than \\eqn{n}, then\n\\eqn{a} raised to the \\eqn{n}th power is congruent to \\eqn{a\\\nmodulo\\ n}{a modulo n}.",  
     value = "Whether the integer passes the Fermat test for a randomized\n\\eqn{0<a<n}",  
     references = "\\url{http://en.wikipedia.org/wiki/Fermat's_little_theorem}",  
     `item{n}` = "the integer to test for primality.", note = "\\code{fermat.test} doesn't work for integers above\napproximately 15 because modulus loses precision."),  
     is.pseudoprime = list(definition = "is.pseudoprime <- structure(function\n### A number is pseudo-prime if it is probably prime, the basis of\n### which is the probabalistic Fermat test; if it passes two such\n### tests, the chances are better than 3 out of 4 that \\eqn{n} is\n### prime.\n##references<< Abelson, Hal; Jerry Sussman, and Julie\n##Sussman. Structure and Interpretation of Computer\n##Programs. Cambridge: MIT Press, 1984.\n(n, ##<< the integer to test for pseudoprimality.\n times ##<< the number of Fermat tests to perform\n){\n  if(times==0)TRUE\n  ##seealso<< \\code{\\link{fermat.test}}\n  else if(fermat.test(n)) is.pseudoprime(n,times-1)\n  else FALSE\n### Whether the number is pseudoprime.\n},ex=function(){\n  is.pseudoprime(13,4)\n})",
         description = "A number is pseudo-prime if it is probably prime, the basis of\nwhich is the probabalistic Fermat test; if it passes two such\ntests, the chances are better than 3 out of 4 that \\eqn{n} is\nprime.",
       title="is pseudoprime",
         references = "Abelson, Hal; Jerry Sussman, and Julie\nSussman. Structure and Interpretation of Computer\nPrograms. Cambridge: MIT Press, 1984.",  
         `item{n}` = "the integer to test for pseudoprimality.",  
         `item{times}` = "the number of Fermat tests to perform",  
         seealso = "\\code{\\link{fermat.test}}", examples = "\nis.pseudoprime(13,4)\n",  
         value = "Whether the number is pseudoprime.",format="")) 

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