chrono::ChVariablesGeneric Class Reference

Description

Specialized class for representing a N-DOF item for a system, that is an item with mass matrix and associate variables.

The main difference from the base class ChVariables is that the base class does not create any mass matrix, while this minimal specialization at least creates a NxN mass matrix. Of course a generic (uncompressed) NxN matrix is used. This means that, for example, this class could be used for 3D rigid bodies if N=6, however it would be better to implement a more optimized class which does not create a full 6x6 matrix (since only few elements on the diagonal would be different from 0 in case of rigid bodies), so use the ChVariablesBody in this case..

#include <ChVariablesGeneric.h>

Inheritance diagram for chrono::ChVariablesGeneric:
Collaboration diagram for chrono::ChVariablesGeneric:

Public Member Functions

 ChVariablesGeneric (unsigned int dof=1)
 
ChVariablesGenericoperator= (const ChVariablesGeneric &other)
 Assignment operator: copy from other object.
 
ChMatrixDynamicGetMass ()
 Access the inertia matrix.
 
ChMatrixDynamicGetInvMass ()
 Access the inverted inertia matrix.
 
virtual void ComputeMassInverseTimesVector (ChVectorRef result, ChVectorConstRef vect) const override
 Compute the product of the inverse mass matrix by a given vector and store in result. More...
 
virtual void AddMassTimesVector (ChVectorRef result, ChVectorConstRef vect) const override
 Compute the product of the mass matrix by a given vector and increment result. More...
 
virtual void AddMassTimesVectorInto (ChVectorRef result, ChVectorConstRef vect, const double ca) const override
 Add the product of the mass submatrix by a given vector, scaled by ca, to result. More...
 
virtual void AddMassDiagonalInto (ChVectorRef result, const double ca) const override
 Add the diagonal of the mass matrix, as a vector scaled by ca, to result. More...
 
virtual void PasteMassInto (ChSparseMatrix &mat, unsigned int start_row, unsigned int start_col, const double ca) const override
 Write the mass submatrix for these variables into the specified global matrix at the offsets of each variable. More...
 
- Public Member Functions inherited from chrono::ChVariables
 ChVariables (unsigned int dof)
 
ChVariablesoperator= (const ChVariables &other)
 Assignment operator: copy from other object.
 
void SetDisabled (bool mdis)
 Deactivates/freezes the variable (these variables won't be modified by the system solver).
 
bool IsDisabled () const
 Check if the variables have been deactivated (these variables won't be modified by the system solver).
 
bool IsActive () const
 Check if these variables are currently active. More...
 
unsigned int GetDOF () const
 The number of scalar variables in the vector qb (dof=degrees of freedom).
 
ChVectorRef State ()
 Get a reference to the differential states encapsulated by these variables. More...
 
ChVectorRef Force ()
 Get a reference to the generalized force corresponding to these variables. More...
 
void SetOffset (unsigned int moff)
 Set offset in the global state vector. More...
 
unsigned int GetOffset () const
 Get offset in the global state vector.
 
virtual void ArchiveOut (ChArchiveOut &archive_out)
 
virtual void ArchiveIn (ChArchiveIn &archive_in)
 

Additional Inherited Members

- Protected Attributes inherited from chrono::ChVariables
unsigned int offset
 offset in global q state vector (needed by some solvers)
 
unsigned int ndof
 number of degrees of freedom (number of contained scalar variables)
 

Member Function Documentation

◆ AddMassDiagonalInto()

void chrono::ChVariablesGeneric::AddMassDiagonalInto ( ChVectorRef  result,
const double  ca 
) const
overridevirtual

Add the diagonal of the mass matrix, as a vector scaled by ca, to result.

Note: 'result' is a system-level vector of appropriate size. This function must index into this vector using the offsets of each variable.

Implements chrono::ChVariables.

◆ AddMassTimesVector()

void chrono::ChVariablesGeneric::AddMassTimesVector ( ChVectorRef  result,
ChVectorConstRef  vect 
) const
overridevirtual

Compute the product of the mass matrix by a given vector and increment result.

This function must perform the operation result += M * vect for a vector of same size as the variables state.

Implements chrono::ChVariables.

◆ AddMassTimesVectorInto()

void chrono::ChVariablesGeneric::AddMassTimesVectorInto ( ChVectorRef  result,
ChVectorConstRef  vect,
const double  ca 
) const
overridevirtual

Add the product of the mass submatrix by a given vector, scaled by ca, to result.

Note: 'result' and 'vect' are system-level vectors of appropriate size. This function must index into these vectors using the offsets of each variable.

Implements chrono::ChVariables.

◆ ComputeMassInverseTimesVector()

void chrono::ChVariablesGeneric::ComputeMassInverseTimesVector ( ChVectorRef  result,
ChVectorConstRef  vect 
) const
overridevirtual

Compute the product of the inverse mass matrix by a given vector and store in result.

This function must calculate result = M^(-1) * vect for a vector of same size as the variables state.

Implements chrono::ChVariables.

◆ PasteMassInto()

void chrono::ChVariablesGeneric::PasteMassInto ( ChSparseMatrix mat,
unsigned int  start_row,
unsigned int  start_col,
const double  ca 
) const
overridevirtual

Write the mass submatrix for these variables into the specified global matrix at the offsets of each variable.

The masses will be scaled by the given factor 'ca'. The (start_row, start_col) pair specifies the top-left corner of the system-level mass matrix in the provided matrix. Assembling the system-level sparse matrix is required only if using a direct sparse solver or for debugging/reporting purposes.

Implements chrono::ChVariables.


The documentation for this class was generated from the following files:
  • /builds/uwsbel/chrono/src/chrono/solver/ChVariablesGeneric.h
  • /builds/uwsbel/chrono/src/chrono/solver/ChVariablesGeneric.cpp