Methods

{
  "name": "MechanicalProjectVelocityVisitor",
  "namespace": "sofa::simulation::mechanicalvisitor",
  "module": "Sofa.framework.Simulation.Core",
  "include": "sofa/simulation/mechanicalvisitor/MechanicalProjectVelocityVisitor.h",
  "doc": "",
  "inherits": [
    "MechanicalVisitor"
  ],
  "templates": [],
  "data_fields": [],
  "links": [],
  "methods": [
    {
      "name": "fwdMechanicalMapping",
      "return_type": "Result",
      "params": [
        {
          "name": "",
          "type": "simulation::Node *"
        },
        {
          "name": "map",
          "type": "sofa::core::BaseMapping *"
        }
      ],
      "is_virtual": true,
      "is_pure_virtual": false,
      "is_static": false,
      "access": "public"
    },
    {
      "name": "fwdProjectiveConstraintSet",
      "return_type": "Result",
      "params": [
        {
          "name": "",
          "type": "simulation::Node *"
        },
        {
          "name": "c",
          "type": "sofa::core::behavior::BaseProjectiveConstraintSet *"
        }
      ],
      "is_virtual": true,
      "is_pure_virtual": false,
      "is_static": false,
      "access": "public"
    },
    {
      "name": "getInfos",
      "return_type": "int",
      "params": [],
      "is_virtual": false,
      "is_pure_virtual": false,
      "is_static": false,
      "access": "public"
    },
    {
      "name": "isThreadSafe",
      "return_type": "bool",
      "params": [],
      "is_virtual": true,
      "is_pure_virtual": false,
      "is_static": false,
      "access": "public"
    }
  ],
  "description": "<p>The <code>MechanicalProjectVelocityVisitor</code> is a visitor class in the SOFA simulation framework, inheriting from <code>MechanicalVisitor</code>. Its primary role is to handle velocity projection in mechanical simulations.</p><p>This component interacts with other parts of the SOFA ecosystem through its inherited and overridden methods. Specifically:</p><ul><li>The <code>fwdMechanicalMapping</code> method, which is part of the visitor pattern, handles forward mapping for mechanical elements but returns <code>RESULT_PRUNE</code>.</li><li>The <code>fwdProjectiveConstraintSet</code> method projects velocity using constraints from a <code>BaseProjectiveConstraintSet</code>, and it continues the processing with <code>RESULT_CONTINUE</code>.</li></ul><p>The component is designed to be thread-safe, as indicated by its <code>isThreadSafe</code> method returning true. This makes it suitable for parallelized simulation processes.</p><p>Its initialization includes setting a time value and velocity identifier. The visitor's role can be understood from the context of mechanical simulations where projecting velocities accurately is crucial for maintaining physical realism in dynamic scenarios.</p>",
  "maths": "The `MechanicalProjectVelocityVisitor` is a specialized visitor in the SOFA framework that facilitates the projection of velocities within mechanical simulations. This component plays a crucial role in ensuring consistency and accuracy during dynamic scenarios, particularly in the context of velocity projections.\n\n### Governing Equations or Operators\n\nThis component does not directly implement traditional FEM operators such as mass matrix $M$, stiffness matrix $K$, internal force $\textbf{f}_{int}$, or residual $\textbf{R}$. Instead, its primary role is to handle the projection of velocities according to constraints and mappings. The key method involved in this process is `fwdProjectiveConstraintSet`, which interfaces with a `BaseProjectiveConstraintSet` to project velocities.\n\nThe velocity projection can be understood as solving for consistent velocities under constraints:\n\\[\textbf{v}_{proj} = \\Pi(\\textbf{v})\n\\]\nwhere $\\textbf{v}$ is the original velocity vector and $\\Pi$ represents a projection operator that ensures the velocities satisfy any imposed constraints.\n\n### Constitutive or Kinematic Laws\n\nThe `MechanicalProjectVelocityVisitor` does not directly involve specific constitutive laws (e.g., stress-strain relationships, hyperelastic potentials) or kinematic measures. Instead, it operates on the level of enforcing physical consistency through velocity projection under mechanical constraints and mappings.\n\n### Role in the Global FEM Pipeline\n\nIn the context of the global FEM pipeline, this component is involved in the constraint handling phase:\n1. **Constraint Handling**: The `fwdProjectiveConstraintSet` method projects velocities to ensure they satisfy any constraints defined by the mechanical model (e.g., contact constraints, boundary conditions). This ensures that the solution remains physically consistent.\n2. **Thread Safety and Parallelization**: Since the component is designed to be thread-safe (`isThreadSafe()` returns `true`), it can be efficiently utilized in parallelized simulation processes.\n\n### Numerical Methods or Discretization Choices\n\nThe projection of velocities does not involve explicit discretization choices such as finite element shape functions or numerical integration schemes. Instead, the focus is on ensuring that velocity updates are consistent with mechanical constraints and mappings within the broader SOFA simulation framework.\n\n### Integration into Variational / Lagrangian Mechanics Framework\n\nIn a variational mechanics context, this component ensures that velocities are projected consistently under constraints, which can be viewed as enforcing the consistency of solutions in terms of generalized coordinates $q$. For example, if constraints are applied to the displacements or velocities, ensuring that these constraints are satisfied is critical for maintaining the physical integrity of the simulation.\n\n\\[\textbf{v}_{proj} = \\Pi(\\dot{\\textbf{q}})\n\\]\nwhere $\\dot{\\textbf{q}}$ represents generalized velocities and $\\Pi$ ensures that these velocities satisfy any imposed constraints. This ensures that the solution remains physically consistent within the Lagrangian mechanics framework.",
  "abstract": "The `MechanicalProjectVelocityVisitor` handles velocity projection within mechanical simulations by enforcing consistency with constraints and mappings, ensuring physical realism in dynamic scenarios.",
  "sheet": "# MechanicalProjectVelocityVisitor\n\n## Overview\n\nThe `MechanicalProjectVelocityVisitor` is a specialized visitor that handles the projection of velocities within mechanical simulations. It inherits from `MechanicalVisitor`, implementing methods for forward mapping (`fwdMechanicalMapping`) and projecting velocities using constraints (`fwdProjectiveConstraintSet`). This component ensures thread safety, making it suitable for parallelized simulation processes.\n\n## Mathematical Model\n\nThe primary role of the `MechanicalProjectVelocityVisitor` is to project velocities under mechanical constraints. The velocity projection can be understood as solving for consistent velocities under constraints:\n\n\begin{equation}\n\\textbf{v}_{proj} = \\Pi(\\textbf{v})\n\\end{equation}\n\nwhere $\\textbf{v}$ is the original velocity vector and $\\Pi$ represents a projection operator that ensures the velocities satisfy any imposed constraints. In a variational mechanics context, this can be viewed as enforcing consistency of solutions in terms of generalized coordinates $q$:\n\n\begin{equation}\n\\textbf{v}_{proj} = \\Pi(\\dot{\\textbf{q}})\n\\end{equation}\n\nwhere $\\dot{\\textbf{q}}$ represents generalized velocities and $\\Pi$ ensures that these velocities satisfy any imposed constraints.\n\n## Practical Notes\n\nThe `MechanicalProjectVelocityVisitor` is designed to be thread-safe (`isThreadSafe()` returns `true`), making it suitable for parallelized simulation processes. This component does not involve explicit discretization choices or numerical integration schemes but focuses on ensuring that velocity updates are consistent with mechanical constraints and mappings within the broader SOFA simulation framework."
}