UDXappend2Ddata(filename,p,t,u,attr_name,attr_rank,attr_shape)

Apends data to a file in DX form.
Only one variable can be written to the file
variable must be a scalar, vector or tensor of doubles
mesh data in the file must be consistent with this variable

x
attr_name  = name of the variable                   (type string)
attr_rank  = rank of variable data                  (0 for scalar, 1 for vector, etc.)
attr_shape = number of components of variable data  (assumed 1 for scalar)