R/vswf.pwe.r

In wendellopes/rvswf: RVSWF: Expansion in Vector Spherical Wave Functions written in R

#' Partial Wave Expansion in Vector Spherical Harmonics.
#' 
#' @details Calculate the electromagnetic fields \eqn{\bm{E}} and \eqn{Z\bm{H}} 
#' as functions of \eqn{G^{TE}_{lm}} and \eqn{G^{TM}_{lm}} for a given position
#' and from 0 to lmax.
#' @param k The module of the wave vector.
#' @param x The component \eqn{x} of the position vector.
#' @param y The component \eqn{y} of the position vector.
#' @param z The component \eqn{z} of the position vector.
#' @param lmax The maximum value of \eqn{l}.
#' @param gte One of the components of the expansion.
#' @param gtm The oder component of the expansion.
#' @return A list with the input values, the position and the
#' values of the electromagnetic fields.
#' @export
#' @examples
#' lambda=.5e-6
#' k=2*pi/lambda
#' lmax<-20
#' a=lambda
#' NP=200
#' z<-seq(-a,a,2*a/(NP-1))
#-------------------------------------------------------------------------------
#' xo<-sample(z,1)
#' yo<-sample(z,1)
#' zo<-sample(z,1)
#-------------------------------------------------------------------------------
#' Em<-exp(1i*k*zo)
#' Ez<-0
#' Ep<-0
#-------------------------------------------------------------------------------
#' Hm<--1i*Em
#' Hz<--1i*Ez
#' Hp<--1i*Ep
#'#-------------------------------------------------------------------------------
#'# MIE PLANE WAVE
#'#-------------------------------------------------------------------------------
#' v<-vswf.hmp(k,xo,yo,zo,lmax)
#' u<-vswf.mpw(lmax,norm=TRUE)
#'#-------------------------------------------------------------------------------
#' Em.pweZ<-sum(u$GTE*v$M.m-u$GTM*v$N.m)
#' Ez.pweZ<-sum(u$GTE*v$M.z-u$GTM*v$N.z)
#' Ep.pweZ<-sum(u$GTE*v$M.p-u$GTM*v$N.p)
#' 
#' Hm.pweZ<-sum(u$GTM*v$M.m+u$GTE*v$N.m)
#' Hz.pweZ<-sum(u$GTM*v$M.z+u$GTE*v$N.z)
#' Hp.pweZ<-sum(u$GTM*v$M.p+u$GTE*v$N.p)
#' #-------------------------------------------------------------------------------
#' # GENERIC PLANE WAVE
#' #-------------------------------------------------------------------------------
#' w<-vswf.gpw(0,0,k,1/sqrt(2),1i/sqrt(2),0,lmax)
#' 
#' Em.pweK<-sum(w$GTE*v$M.m-w$GTM*v$N.m)
#' Ez.pweK<-sum(w$GTE*v$M.z-w$GTM*v$N.z)
#' Ep.pweK<-sum(w$GTE*v$M.p-w$GTM*v$N.p)
#' 
#' Hm.pweK<-sum(w$GTM*v$M.m+w$GTE*v$N.m)
#' Hz.pweK<-sum(w$GTM*v$M.z+w$GTE*v$N.z)
#' Hp.pweK<-sum(w$GTM*v$M.p+w$GTE*v$N.p)
#' #-------------------------------------------------------------------------------
#' # CHECKING
#' #-------------------------------------------------------------------------------
#' b<-data.frame(DEF=c(Em,Ez,Ep,Hm,Hz,Hp),
#'               row.names=c("Em","Ez","Ep","Hm","Hz","Hp"))
#' b$MPW<-c(Em.pweZ,Ez.pweZ,Ep.pweZ,Hm.pweZ,Hz.pweZ,Hp.pweZ)
#' b$GPW<-c(Em.pweK,Ez.pweK,Ep.pweK,Hm.pweK,Hz.pweK,Hp.pweK)
#' print(b)
vswf.pwe<-function(k,x,y,z,lmax,gte,gtm)
{
x[x==0]<-.Machine$double.xmin
y[y==0]<-.Machine$double.xmin
z[z==0]<-.Machine$double.xmin
nx<-length(x)
ny<-length(y)
nz<-length(z)
dummy<-rep(0,nx*ny*nz)
.C("vswf_pwe",
   k=as.double(k),
   x=as.double(x),
   y=as.double(y),
   z=as.double(z),
   lmax=as.integer(lmax),
   nx=as.integer(nx),
   ny=as.integer(ny),
   nz=as.integer(nz),
   GTE=as.complex(gte),
   GTM=as.complex(gtm),
   rx=as.double(dummy),
   ry=as.double(dummy),
   rz=as.double(dummy),
   Em=as.complex(dummy),
   Ez=as.complex(dummy),
   Ep=as.complex(dummy),
   Hm=as.complex(dummy),
   Hz=as.complex(dummy),
   Hp=as.complex(dummy)
   )
}