function var = ns_t6_var_set ( element_num, element_node, node_num, ...
var_node, var_num )
%*****************************************************************************80
%
%% ns_t6_var_set() sets the Navier Stokes variables on a T6 grid.
%
% Discussion:
%
% We are given a mesh of T6 elements, and asked to create the natural
% list of indices for Navier-Stokes variables associated with each node.
% In particular, every node has two velocity variables associated with
% it, but only a node that is a vertex of the element will also have
% an associated pressure variable.
%
% The hard work has been done for us alread, because the variables
% have been counted, and the pointers to the occurrence of the
% first variable associated with each node have been created.
%
% The indexing of the nodes can be arbitrary, although a bad
% indexing will result in a miserably large bandwidth (if band
% storage is being tried for the stiffness matrix). Here, we
% simply try to natural ordering, that is, the variables are
% numbered in order of the node with which they are associated.
%
% For the Navier Stokes problem on a T6 grid, we take it as
% understood that each node has either 2 or 3 variables associated
% with it, that the first two are always the horizontal and
% then vertical velocity coefficients, and that the third, if
% present, is a pressure coefficient.
%
% In other settings, it might be necessary not merely to assign
% the variables an index, but also to identify them as to type.
%
% Licensing:
%
% This code is distributed under the MIT license.
%
% Modified:
%
% 14 February 2003
%
% Author:
%
% John Burkardt
%
% Input:
%
% integer ELEMENT_NUM, the number of elements.
%
% integer ELEMENT_NODE(ELEMENT_ORDER,ELEMENT_NUM);
% ELEMENT_NODE(I,J) is the global index of local node I in element J.
%
% integer NODE_NUM, the number of nodes.
%
% integer VAR_NODE(NODE_NUM+1), used to find the variables
% associated with a given node, which are in VAR in locations
% VAR_NODE(NODE) to VAR_NODE(NODE+1)-1. Note that the last entry of
% this array points to the location just after the last location in VAR.
%
% integer VAR_NUM, the number of variables.
%
% Output:
%
% integer VAR(VAR_NUM), the indexes of the variables, which
% are simply 1, 2, 3, ..., VAR_NUM.
%
for i = 1 : var_num
var(i) = i;
end
return
end