R help - Jun 2014 - hypergeometric integral

Dear all,

I am trying to make a numerical integral of a Hypergeometrical function 2F1
but it is not working. I dont know how to pass the arguments to my
function. Thank you beforehand.
Chuse.

Here is my code:

H <- 0.7;

t <- 1;
s <- seq(0,t,0.1);
x <- 1-t/s;

library(gsl)
Gauss2F1 <- function(H,x){
  a <- H-1/2;
  b <- 1/2-H;
  c <- H+1/2;
#  if(x>=0 & x<1){
#    hyperg_2F1(a,b,c,x)
#  }else{
    hyperg_2F1(c-a,b,c,1-1/(1-x))/(1-x)^b
#  }
}

F <- Gauss2F1(a,b,c,x)

integrate(F,lower=-1,upper=1,H=0.7)

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#First, correct your code
H <- 0.7;

t <- 1;
s <- seq(0,t,0.1);
x <- 1-t/s;

library(gsl)
Gauss2F1 <- function(H,x){
  a <- H-1/2;
  b <- 1/2-H;
  c <- H+1/2;
  #  if(x>=0 & x<1){
  #    hyperg_2F1(a,b,c,x)
  #  }else{
  hyperg_2F1(c-a,b,c,1-1/(1-x))/(1-x)^b
  #  }
}

#Here
#F <- Gauss2F1(a,b,c,x)
#and here
#integrate(F,lower=0,upper=1,H=0.7)

integrate(Gauss2F1,lower=0,upper=1,H=0.7)

Error in integrate(Gauss2F1, lower = 0, upper = 1, H = 0.7) : 
  non-finite function value

#Then note that
Gauss2F1(H,x)
 [1]      Inf 1.143016 1.083553 1.056065 1.039444 1.028055 1.019653 
1.013143 1.007920 1.003618
[11] 1.000000
#whereupon you find your second problem.
#Joe



Xuse Chuse <chuse22@gmail.com> 
Sent by: r-help-bounces@r-project.org
06/17/2014 08:32 AM

To
r-help <r-help@r-project.org>, 
cc

Subject
[R] hypergeometric integral






Dear all,

I am trying to make a numerical integral of a Hypergeometrical function 
2F1
but it is not working. I dont know how to pass the arguments to my
function. Thank you beforehand.
Chuse.

Here is my code:

H <- 0.7;

t <- 1;
s <- seq(0,t,0.1);
x <- 1-t/s;

library(gsl)
Gauss2F1 <- function(H,x){
  a <- H-1/2;
  b <- 1/2-H;
  c <- H+1/2;
#  if(x>=0 & x<1){
#    hyperg_2F1(a,b,c,x)
#  }else{
    hyperg_2F1(c-a,b,c,1-1/(1-x))/(1-x)^b
#  }
}

F <- Gauss2F1(a,b,c,x)

integrate(F,lower=-1,upper=1,H=0.7)

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