% ATMDATA_DIMADD expands dimensionality of atmdata
%
%   The function adds dimensions to data having
%   the atmdata structure, by a simple expansion 
%   of the data.
%   0-Dimension (0-D) data can be expanded to
%   1-D, 2-D, or 3-D data.
%   1-D data can be expanded to 2-D or 3-D. 
%   2-D data can be expaned to 3-D.
%
%   FORMAT [Gout]=atmdata_dimadd(G,grids)
%
%   IN    G       an atmdata structure
%         grids   a cell array of the new grids
%         to be used for the expansion. 
%         grids{1} is assumed to be the first
%         dimension to be added. 
%
%   OUT   Gout an atmdata structure with
%         new data dimensionallity.
%
%   Example usage:
%   Here is an example how to expand 0-D data
%   to 1-D:
%   G0D = atmdata_scalar( 0.7814 ); %0-D data
%   G0D.NAME = 'N2';
%   G0D.DATA_NAME = 'Volume mixing ratio';
%   G0D.DATA_UNIT = '-';
%   p_grid = vec2col(z2p_simple([-1e3:1e3:25e3 30e3:5e3:70e3]));
%   grids = {p_grid};
%   [G1D]=atmdata_dimadd(G0D,grids); % 1-D data
%   We will now expand this data to 3-D
%   lat_grid = vec2col([-4:0.5:4]);
%   lon_grid = vec2col([23:0.5:27]);
%   grids = {lat_grid, lon_grid};
%   [G3D]=atmdata_dimadd(G1D,grids); 

function [Gout]=atmdata_dimadd(G,grids)

strictAssert = atmlab('STRICT_ASSERT');

if strictAssert; 
  rqre_datatype( G, @isatmdata );
  if ~iscell(grids);
    error('grids must be a cell array.')
  end
  if length(grids)>4;
    error('length of grids must be less than 5.')
  end
  for i=1:length(grids);
    if ~isvector(grids{i});
      error('the elements of grids should be a vector.')
    end
  end 
  if G.DIM>2;
    error('This function does not handle G.DIM>2.')
  end
end

newdim = G.DIM + length(grids);

Gout = atmdata_empty(newdim);
Gout.NAME = G.NAME;
Gout.DATA_NAME = G.DATA_NAME;
Gout.DATA_UNIT = G.DATA_UNIT;
Gout.SOURCE = G.SOURCE; 
if newdim==4;
  Gout.GRID4_NAME='MJD';
  Gout.GRID4_UNIT='mjd';
end

%write new grids to Gnew 
mapdata=[];
for i=1:G.DIM;
   Gout.(sprintf('GRID%d',i))=vec2col(G.(sprintf('GRID%d',i)));
   mapdata(i)=length(Gout.(sprintf('GRID%d',i)));
end
for i=1:length(grids)
  Gout.(sprintf('GRID%d',G.DIM+i))=vec2col(grids{i});
  mapdata(G.DIM+i)=length(grids{i});
end


if G.DIM==1;
  mapdata(1)=1;
end
if G.DIM==2;
  mapdata(1)=1;
  mapdata(2)=1;
end
mapdata(end+1)=1;

Gout.DATA=repmat(G.DATA,mapdata);