Laygo architecture

../_images/architecture.pngLaygo package structure

Laygo package has 10 submodules, classified into 4 categories; Generator, Database, Object, and IO.

  • Generator modules interact with user input (scripts) and command database and IO modules to do actual layout generation jobs. There are 2 generator modules implemented in laygo.

    • BaseLayoutGenerator: generates layout on physical grids.
    • GridLayoutGenerator: generates layout on abstract grids.
    • GridLayoutGenerator2: improved version of GridLayoutGenerator. Not backward compatible.

    Since the GridLayoutGenerator class is based on BaseLayoutGenerator, users may instantiate the GridLayoutGenerator even for physical grid tasks.

  • Database modules store the design hierarchary (as a form of Python dictionary). 3 types of Database modules are used.

    • LayoutDB: stores layout data (Rects, Instances, Pins, …)
    • TemplateDB: stores template data for placements
    • GridDB: stores grid data for placements and routings

  • Object modules compose the database module and implement actual layout/template/grid components.

    • LayoutObject: implements layout objects. Supported types are Rect, Pin, Text, and Instance.
    • TemplateObject: implements templates.
    • GridObject: implements grids. The GridObject class has PlacementGrid and RouteGrid as derived classes.

  • IO modules import/export generated layout data in various formats. While template and grid IO functions are embedded in TemplateDB and GridDB classes, separate modules are implemented for layout objects for their complexity.

    • LayoutIO is used for importing / exporting layout data. Currently it supports 2 options: BAG and GDS. Yaml/OA/Skill/pyplot options will be supported in later versions.
    • GDSIO is a dedicated class for GDS file support.