Mastering Path Attributes in SAMSON’s Node Specification Language (NSL)

For molecular modelers who regularly use SAMSON for integrative molecular design, efficiently querying and manipulating molecular structures is essential. One of the common challenges is specifying paths with precise characteristics, such as the number of atoms or selection status. This blog post dives into the path attribute space within SAMSON’s Node Specification Language (NSL), offering insights into its capabilities and how it can make your modeling tasks more efficient.

Understanding Path Attributes

The path attribute space in NSL (short name: p) is designed to match conformation nodes with specific properties. Whether you’re interested in working with paths based on the number of atoms, selection status, or other inherited attributes, the path space provides powerful tools for precise queries within SAMSON.

Key Path Attributes

The attributes in the path space can be divided into two categories:

  • Inherited attributes: These are attributes shared with the node space, such as name, selected, and selectionFlag.
  • Specific attributes: Attributes unique to the path space, like numberOfAtoms.

Applying Path Attributes

Let’s explore some practical applications of the key path attributes:

1. The name Attribute

The name attribute (p.n) lets you select paths based on their names. You can use exact matches or pattern-based searches. For example:

  • p.n "A": Selects paths named “A”.
  • p.n "L*": Matches paths with names starting with “L”.

This is especially useful for identifying specific conformations or structural components in large molecular systems.

2. The numberOfAtoms Attribute

This attribute (p.nat) allows you to match paths based on the number of atoms they contain. For instance:

  • p.nat > 100: Matches paths with more than 100 atoms.
  • p.nat 100:200: Selects paths containing between 100 and 200 atoms.

This is ideal for refining your modeling focus by selecting paths that fit specific size criteria.

3. The selected and selectionFlag Attributes

The selected attribute and selectionFlag (p.sf) provide tools for working with selection states:

  • p.selected: Matches paths that are currently selected.
  • not p.selected: Matches paths that are not selected.
  • p.sf false: Matches paths with selectionFlag set to false.

Selection attributes are particularly helpful for managing workflows involving multiple conformations or when focusing on highlighted regions of a model.

Why Use Path Attributes?

The path attribute space enhances your ability to efficiently filter and manipulate molecular structures. Instead of sifting through all nodes manually, targeted expressions using attributes like p.name, p.nat, or p.sf save time and reduce errors in large-scale projects.

Learn More

For a deeper dive into all attributes and their usage, check out the complete path attributes reference on the documentation page.

SAMSON and all SAMSON Extensions are free for non-commercial use. You can get SAMSON at SAMSON Connect.

Comments are closed.