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Subsets

  Spock allows the user to define subsets of atoms and surfaces and give those subsets names. Those subsets can later be referenced by the given name. The command subdef= discussed in § 5.2.7 may be used to create a subset, and the selection string sub=NAME5.3.2) may be used to select a subset. For vertex subsets, the corresponding commands are vsubdef and vsub=. Note that in spock, atom and vertex subsets are entirely separate, and do not share the same name space. You may define an atom and a vertex subset with the same name, but the vertex subset will refer only to vertices and the atom subset will refer only to atoms. Subset definitions are static, in that once defined, a subset remains constant, even if the values on which the defining expression depend change.

The subset menu expands on the subset commands and provides a more convenient user interface for subsetting commands. Up to 28 user-defined atom subsets may be active at one time. (The upper limit is because subsets are stored internally as one bit of a 32-bit integer array, and bits 0 through 3 are reserved for internal use.) Up to 26 surface subsets may be defined. (Bits 0 through 5 are reserved.) An individual atom or vertex may belong to any number of subsets. Subsets may also be referred to by number in a selection string (e.g. bc=0,sub=1). Subsets are numbered sequentially starting with 1. Again, atom and vertex subsets are separate, so there is a atom subset numbered 1 and a distinct vertex subset numbered 1 if they have been created. If you delete a subset, all following subsets are renumbered so that there are no gaps in the numbering sequence.         It is also possible to graphically define vertex (surface) subsets via the ``Surface selection'' commands of the ``Graphics tex2html_wrap_inline6800 Mouse bindings'' menu, as described in §6.11.3. There are two names that are reserved for graphically defined vertex subsets, vsub=MARKED and vsub=FILLED. These names should not be used for any other user-defined surface subsets.

The menu options to control subsets are similar for atoms and surfaces, and are described in general terms below:

 
next up gif contents index
Next: Picking Up: Menus Previous: Modeling

Jon Christopher
Tue Sep 14 16:44:48 CDT 1999