Demystifying Path Attributes in SAMSON’s Node Specification Language

Molecular modelers often need efficient ways to specify and filter molecular structures when working with a large dataset. This is where understanding and utilizing path attributes in SAMSON’s Node Specification Language (NSL) becomes crucial. These attributes help in targeting specific molecular nodes, particularly conformation nodes, with precision. In this blog post, we’ll walk through the key path attributes to streamline your molecular modeling workflows.

1. What’s Special About Path Attributes?

The path attribute space is a dedicated system in SAMSON’s NSL that applies specifically to conformation nodes. It comes with its own tailored set of attributes and examples, allowing molecular modelers to conduct highly-specific attribute-based searches and selections. This can save time and effort, especially when working with extensive molecular structures.

Some of these attributes are inherited from the general node attribute space, while others are unique to path. Let’s explore both categories.

2. Key Path Attributes

Here, we summarize the key attributes of the path attribute space to illustrate how they can be leveraged in your projects.

Attributes Inherited from node:

  • name: Use path.name (short form: p.n) to filter by string-based names, for example, p.n "A" or p.n "L*", where L* uses a wildcard to match names starting with ‘L’.
  • selected: path.selected matches nodes that are selected in the current workspace. You can also exclude selected nodes using expressions like not path.selected.
  • selectionFlag: This attribute, with short form sf, specifies whether nodes are marked with a selection flag. For example, you can use path.sf false to exclude selection-flagged nodes.

Attributes Unique to path:

  • numberOfAtoms: Use the attribute path.numberOfAtoms (short form: p.nat) to target paths based on atom count. For instance:
    • p.nat > 100: Matches paths with more than 100 atoms.
    • p.nat 100:200: Matches paths with atoms numbering between 100 and 200.

3. Why These Attributes Matter

Imagine working on a molecular modeling project where you need to filter conformations exceeding a specific number of atoms or isolate selected paths marked by a flag. Instead of manually navigating and inspecting data, path attributes allow you to automate these operations with concise expressions. This can significantly improve efficiency in molecular modeling and reduce human error.

4. Quickstart Examples

To get you started, here are some practical examples of how you might use path attributes in SAMSON:

  • path.n "Ligand1" – Locate paths named ‘Ligand1’.
  • not path.selected – Isolate paths that are currently not selected.
  • path.sf true – Focus on paths flagged with the selection flag.
  • path.nat > 150 – Filter paths with more than 150 atoms.

Such use cases demonstrate the versatility of path attributes to refine searches and tailor workflows for specific goals in molecular modeling.

5. Learn More

To dive deeper into the details of path attributes and NSL, you can explore the full documentation page here.

SAMSON and all SAMSON Extensions are free for non-commercial use. To get started, visit SAMSON.

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