schrodinger.trajectory.atomselection.FrameAslSelection

init(self, asl_expr, is_dynamic=None)
(Constructor)

x.__init__(...) initializes x; see help(type(x)) for signature

Overrides: object.__init__: (inherited documentation)

isDynamic(self)

Returns:: A bool indicating whether this selection changes from frame to frame.

getAtomIndices(self, frame)

Returns:: A selection as a sequence of integers, using one based indexing so it can be used with a Structure.

getOffsets(self, frame)

Returns:: A selection as a sequence of integers, using zero based indexing so it can be used with a numpy array.

getArraySelection(self, frame)

Returns:: A selection as a sequence of integers, using zero based indexing so it can be used with a numpy array.

createIndexSelection(self, frame, cmp=None, key=None)

Create a FrameIndexSelection from this instance.

Because FrameAslSelections do not imply an ordering of atoms, two methods of ordering the new selection are available. The first is to provide a cmp method. This method should expect two _StructureAtom instances as arguments and should behave like the cmp argument to the sort method of the built-in list. The second ordering method is to specify a _StructureAtom attribute on which to sort.

If neither of these is specified, the selection will be returned in order of atom indices. In this case, the frame instance is not needed and can be specified as None.

Raises a ValueError if the FrameAslSelection is dynamic.

Parameters:

cmp (callable) - A comparison function expecting two _StructureAtom instances.
key (str) - A _StructureAtom attribute on which to order the selection.
frame (_DesmondFrame)

Returns: FrameIndexSelection

A FrameIndexSelection with the same atom selection as the current instance.