R/embeddingR6_vecs.R

In mrparker909/MGLMRiem: Multivariate Generalized Linear Models on Riemannian Manifolds

# function Vnew = embeddingR6_vecs(p,V)
# %EMBEDDINGR6_VECS embeds a set of tangnet vectors V in TpM onto R6. This transports V from TpM to T_{I}M.
# %
# %   This will be replaced later with the group action for n x n spd matrix and a vectorization. 
# %    
# %   Vnew = EMBEDDINGR6_VECS(p,V)
# %
# %   See also INVEMBEDDINGR6_VECS, LOGMAP_SPD
# 
# %   Hyunwoo J. Kim
# %   $Revision: 0.1 $  $Date: 2014/06/23 15:16:53 
# 
# if length(size(V)) == 2
# Vnew = embeddingR6(p, V);
# return;
# elseif length(size(V)) == 3
# nmx = size(V,3);
# Vnew = zeros(6,nmx);
# for i=1:nmx
# Vnew(:,i) = embeddingR6(p, V(:,:,i));
# end
# else
#   error('V is wrong input.');
# end

#' @export
embeddingR6_vecs <- function(p,V) {
#EMBEDDINGR6_VECS embeds a set of tangnet vectors V in TpM onto R6. This transports V from TpM to T_{I}M.
#
#   This will be replaced later with the group action for n x n spd matrix and a vectorization. 
#    
#   Vnew = EMBEDDINGR6_VECS(p,V)
#
#   See also INVEMBEDDINGR6_VECS, LOGMAP_SPD

#   Hyunwoo J. Kim
#   $Revision: 0.1 $  $Date: 2014/06/23 15:16:53 

#   Migrated to R by Matthew RP Parker
#   $Revision: 0.2 $  $Date: 2019/06/17 $ 
  
  if(length(sizeR(V)) == 2) {
    Vnew = embeddingR6(p, V)
  } else if(length(sizeR(V)) == 3) {
    nmx = sizeR(V,3)
    Vnew = array(0, dim=c(6,nmx))
    for(i in 1:nmx) {
      Vnew[,i] = embeddingR6(p, v = V[,,i])
    }
  } else {
    stop('V is wrong input.')
  }

  return(Vnew)
}