09c7633a76
This change introduces methods to cache and load the computed stiffness matrix and nodal masses for flex elements. The cache key is generated based on material properties (Young's modulus, Poisson's ratio), interpolation order, and the bounding box of the flex. This avoids redundant expensive computations when compiling models with identical flex definitions. PiperOrigin-RevId: 874689771 Change-Id: I6d1e299baf294a984b507e2a2602b2c068610536