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function: smooth_val $steps
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keyboard equivalent: none

The "vo" (val-only) radio button (lower right on
the larger F3 panel) causes the "SMOOTH" button
to smooth real (or complex) data without
smoothing the stat mask field.

If real-valued data, surface-smooth the val field
(vertex[i].val).

If complex-valued data (complexvalflag=1),
surface-smooth both val and val2 fields
(vertex[i].val and vertex[i].val2).

The stat mask field will *not* be smoothed, even
if it is loaded (use the "val" radio button to
also smooth the stat field if loaded).

Here are tcl script commands for 10 steps (~3 mm
FWHM) of surface-smoothing of already-read-in
complex data (what SMOOTH button does with
complex data):

  swap_val_val2
  smooth_val 10
  swap_val_val2
  smooth_val 10

Here is the equivalent command executed for
real-valued data:

  smooth_val 10
