bandwidth.m: Add new function. * NEWS: Announce new function. * scripts/linear-algebra/module.mk: New function added to the build system. * scripts/help/__unimplemented__.m: New function removed from unimplemented. * scripts/linear-algebra/isbanded.m: New function added as documentation reference. * scripts/linear-algebra/isdiag.m: New function added as documentation reference. * scripts/linear-algebra/istril.m: New function added as documentation reference. * scripts/linear-algebra/istriu.m: New function added as documentation reference. * scripts/linear-algebra/bandwidth.m: New function. * linalg.txi: Add bandwidth function to manual.

#include <octave/oct.h>

DEFUN_DLD (addtwomatrices, args, , "Add A to B")
{
  int nargin = args.length ();

  if (nargin != 2)
    print_usage ();
  else
    {
      NDArray A = args(0).array_value ();
      NDArray B = args(1).array_value ();
      if (! error_state)
        return octave_value (A + B);
    }

  return octave_value_list ();
}