fem_scalar_component.m

function [scalar_dofs, scalar_df_info] = fem_scalar_component(dofs,ncomp,df_info)
%function [scalar_dofs, scalar_df_info] = fem_scalar_component(dofs,ncomp,df_info)
%
% extract single component ncomp of vectorial discrete function and 
% generate new scalar fem function dof vector of same degree.
%
% params must provide params.pdeg, params.nelements, params.dimrange
% params.ndofs

% Bernard Haasdonk 12.1.2011

indices = (0:(df_info.ndofs/df_info.dimrange-1))*df_info.dimrange + ncomp;
scalar_dofs = dofs(indices)';
scalar_params = [];
scalar_params.dimrange = 1;
scalar_params.pdeg = df_info.pdeg;
% perhaps need more in scalar_params
scalar_df_info = feminfo(scalar_params,df_info.grid);