Dear R users, I'm porting a piece of Matlab code to R, but I'm now stuck with the following: I need an equivalent of besselJ(x, nu) that can handle a complex argument x. I couldn't find any R implementation. I did find a possible fortran solution in SLATEC (< http://www.netlib.org/slatec/ > , CBESJ-C), however I've never tried to use external C or Fortran code together with my R code, so I'm not sure where to go for a simple solution. Any advice welcome, Best regards baptiste _____________________________ Baptiste Augui? Physics Department University of Exeter Stocker Road, Exeter, Devon, EX4 4QL, UK Phone: +44 1392 264187 http://newton.ex.ac.uk/research/emag http://projects.ex.ac.uk/atto
Bessel functions of complex argument
3 messages · Baptiste Auguie, robin hankin
Hello Baptiste Bessel functions with complex arguments are not supported in R. Neither matlab nor the Gnu Scientific Library support them either. . . . but . . . the pari/gp system (released on the GPL) does: ? besselj(1+I,3) %3 = 0.6919067491368555819808728680 + 0.4484268613977010268818252591*I ? You can access some pari/gp functionality from within R by using the elliptic package, although unfortunately its wrapper function, P.pari(), is not quite flexible enough to deal with besselj(). I'd be happy to discuss this offline; P.pari() will need only minor changes to accommodate besselj(). HTH Robin
On 9 Mar 2008, at 13:44, baptiste Augui? wrote:
Dear R users, I'm porting a piece of Matlab code to R, but I'm now stuck with the following: I need an equivalent of besselJ(x, nu) that can handle a complex argument x. I couldn't find any R implementation. I did find a possible fortran solution in SLATEC (< http://www.netlib.org/slatec/
, CBESJ-C), however I've never tried to use external C or Fortran
code together with my R code, so I'm not sure where to go for a simple solution. Any advice welcome, Best regards baptiste
_____________________________ Baptiste Augui? Physics Department University of Exeter Stocker Road, Exeter, Devon, EX4 4QL, UK Phone: +44 1392 264187 http://newton.ex.ac.uk/research/emag http://projects.ex.ac.uk/atto ______________________________________________ R-help at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
-- Robin Hankin Uncertainty Analyst and Neutral Theorist, National Oceanography Centre, Southampton European Way, Southampton SO14 3ZH, UK tel 023-8059-7743
2 days later
Many thanks for this information! I'm pretty sure Matlab can handle complex argument in besselj, although i haven't checked myself, < http://www.mathworks.com/access/helpdesk/help/techdoc/index.html?/ access/helpdesk/help/techdoc/ref/besselj.html > After some more thinking, it turns out my code doesn't need a complex argument at the moment, i can live with the simplest case where it is real. Good to know where to go if this is to change in the future, though. Thanks again, baptiste
On 10 Mar 2008, at 08:49, Robin Hankin wrote:
Hello Baptiste Bessel functions with complex arguments are not supported in R. Neither matlab nor the Gnu Scientific Library support them either. . . . but . . . the pari/gp system (released on the GPL) does: ? besselj(1+I,3) %3 = 0.6919067491368555819808728680 + 0.4484268613977010268818252591*I ? You can access some pari/gp functionality from within R by using the elliptic package, although unfortunately its wrapper function, P.pari(), is not quite flexible enough to deal with besselj(). I'd be happy to discuss this offline; P.pari() will need only minor changes to accommodate besselj(). HTH Robin On 9 Mar 2008, at 13:44, baptiste Augui? wrote:
Dear R users, I'm porting a piece of Matlab code to R, but I'm now stuck with the following: I need an equivalent of besselJ(x, nu) that can handle a complex argument x. I couldn't find any R implementation. I did find a possible fortran solution in SLATEC (< http://www.netlib.org/ slatec/
, CBESJ-C), however I've never tried to use external C or Fortran
code together with my R code, so I'm not sure where to go for a simple solution. Any advice welcome, Best regards baptiste
_____________________________ Baptiste Augui? Physics Department University of Exeter Stocker Road, Exeter, Devon, EX4 4QL, UK Phone: +44 1392 264187 http://newton.ex.ac.uk/research/emag http://projects.ex.ac.uk/atto ______________________________________________ R-help at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting- guide.html and provide commented, minimal, self-contained, reproducible code.
-- Robin Hankin Uncertainty Analyst and Neutral Theorist, National Oceanography Centre, Southampton European Way, Southampton SO14 3ZH, UK tel 023-8059-7743
_____________________________ Baptiste Augui? Physics Department University of Exeter Stocker Road, Exeter, Devon, EX4 4QL, UK Phone: +44 1392 264187 http://newton.ex.ac.uk/research/emag http://projects.ex.ac.uk/atto