For molecular modelers, managing complex molecular configurations efficiently can often feel like navigating a labyrinth. One specific challenge is filtering and specifying path-related properties within molecular systems. Here’s where SAMSON’s Path Attributes in the Node Specification Language (NSL) can make a difference. This guide will introduce you to key aspects of Path Attributes, helping you simplify and accelerate your modeling workflow.
What Are Path Attributes?
Path Attributes belong to the path attribute space (with the short name p) in SAMSON’s NSL. They are specifically designed to match conformation nodes and include inherited attributes from the general node attribute space as well as path-specific attributes. By understanding and utilizing these attributes, you can target particular subsets of your molecular model, ensuring more precise analyses or modifications.
Inherited Path Attributes
The following attributes are inherited from the general node attribute space:
- name (
n): Matches paths based on their string name. For example:p.n "A": Matches paths namedA.p.n "L*": Matches paths with names starting with"L".
- selected: Matches paths based on whether they are part of the selection. Examples include:
p.selected: Matches paths currently selected.not p.selected: Matches paths that are not selected.
- selectionFlag (
sf): Filters paths based on their selection flag. For instance:p.sf false: Matches paths with the selection flag set asfalse.p.sf: Matches paths where the flag exists (true by default).
Path-Specific Attributes
Beyond inherited attributes, the path attribute space introduces its unique attribute:
- numberOfAtoms (
nat): This attribute is essential for managing paths with specific atom counts. Examples include:p.nat > 100: Matches paths containing more than 100 atoms.p.nat 100:200: Matches paths with atom counts between 100 and 200.
The numberOfAtoms attribute is particularly useful for filtering paths in large systems, enabling streamlined workflows when dealing with multi-conformer scenarios.
How to Use Path Attributes Effectively
Understanding how to compose expressions with these attributes can transform how you analyze molecular systems. By combining inherited and unique Path Attributes, you could:
- Focus only on specific molecular conformers of interest (e.g., those sharing a common naming scheme).
- Quickly filter out paths that don’t meet a desired selection or count threshold.
- Develop NSL scripts to automate commonly used path queries, saving time across iterative workflows.
Pairing these attributes with SAMSON’s broader capabilities will empower you to model and analyze molecular systems more precisely and efficiently.
To delve deeper, explore the official SAMSON documentation on the Path Attributes page.
*Note: SAMSON and all SAMSON Extensions are free for non-commercial use. You can download SAMSON at https://www.samson-connect.net.