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## -*- texinfo -*-
## @deftypefn {} {retval =} AbsRel_norm (@var{x}, @var{x_old}, @var{AbsTol}, @var{RelTol}, @var{normcontrol}, @var{y})
## Undocumented internal function.
## @end deftypefn

function retval = AbsRel_norm (x, x_old, AbsTol, RelTol, normcontrol, y = zeros (size (x)))

  if (normcontrol)
    sc = max (AbsTol(:), RelTol * max (sqrt (sumsq (x)), sqrt (sumsq (x_old))));
    retval = sqrt (sumsq ((x - y))) / sc;
  else
    sc = max (AbsTol(:), RelTol .* max (abs (x), abs (x_old)));
    retval = max (abs (x - y) ./ sc);
  endif

endfunction