Description
Specialized class for representing a NDOF 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>
Public Member Functions  
ChVariablesGeneric (int m_ndof=1)  
ChVariablesGeneric &  operator= (const ChVariablesGeneric &other) 
Assignment operator: copy from other object.  
ChMatrix &  GetMass () 
Access the inertia matrix.  
ChMatrix &  GetInvMass () 
Access the inverted inertia matrix.  
virtual int  Get_ndof () const override 
The number of scalar variables in the vector qb (dof=degrees of freedom)  
virtual void  Compute_invMb_v (ChMatrix< double > &result, const ChMatrix< double > &vect) const override 
Computes the product of the inverse mass matrix by a vector, and add to result: result = [invMb]*vect.  
virtual void  Compute_inc_invMb_v (ChMatrix< double > &result, const ChMatrix< double > &vect) const override 
Computes the product of the inverse mass matrix by a vector, and increment result: result += [invMb]*vect.  
virtual void  Compute_inc_Mb_v (ChMatrix< double > &result, const ChMatrix< double > &vect) const override 
Computes the product of the mass matrix by a vector, and set in result: result = [Mb]*vect.  
virtual void  MultiplyAndAdd (ChMatrix< double > &result, const ChMatrix< double > &vect, const double c_a) const override 
Computes the product of the corresponding block in the system matrix (ie. More...  
virtual void  DiagonalAdd (ChMatrix< double > &result, const double c_a) const override 
Add the diagonal of the mass matrix scaled by c_a, to 'result'. More...  
virtual void  Build_M (ChSparseMatrix &storage, int insrow, int inscol, const double c_a) override 
Build the mass matrix (for these variables) scaled by c_a, storing it in 'storage' sparse matrix, at given column/row offset. More...  
Public Member Functions inherited from chrono::ChVariables  
ChVariables (int m_ndof)  
ChVariables &  operator= (const ChVariables &other) 
Assignment operator: copy from other object.  
void  SetDisabled (bool mdis) 
Deactivates/freezes the variable (these 'frozen', variables won't be modified by the system solver). More...  
bool  IsDisabled () const 
Tells if the variables have been deactivated (these 'frozen', variables won't be modified by the system solver). More...  
bool  IsActive () const 
Tells if these variables are currently active, in general, that is tells if they must be included into the system solver or not. More...  
ChMatrix &  Get_qb () 
Returns reference to qb, bodyrelative part of degrees of freedom q in system:  M Cq'*q  f= 0 , c>0, l>0, l*r=0;  Cq 0  l b c.  
virtual void  Compute_fb () 
Compute fb, bodyrelative part of known vector f in system. More...  
ChMatrix &  Get_fb () 
Returns reference to fb, bodyrelative part of known vector f in system. More...  
void  SetOffset (int moff) 
Set offset in global q vector (set automatically by ChSystemDescriptor)  
int  GetOffset () const 
Get offset in global q vector.  
virtual void  ArchiveOUT (ChArchiveOut &marchive) 
virtual void  ArchiveIN (ChArchiveIn &marchive) 
Additional Inherited Members  
Protected Attributes inherited from chrono::ChVariables  
int  offset 
offset in global q state vector (needed by some solvers)  
Member Function Documentation

overridevirtual 
Build the mass matrix (for these variables) scaled by c_a, storing it in 'storage' sparse matrix, at given column/row offset.
Note, most iterative solvers don't need to know mass matrix explicitly.
Implements chrono::ChVariables.

overridevirtual 
Add the diagonal of the mass matrix scaled by c_a, to 'result'.
NOTE: the 'result' vector must already have the size of system unknowns, ie the size of the total variables&constraints in the system; the procedure will use the ChVariable offset (that must be already updated) as index.
Implements chrono::ChVariables.

overridevirtual 
Computes the product of the corresponding block in the system matrix (ie.
the mass matrix) by 'vect', scale by c_a, and add to 'result'. NOTE: the 'vect' and 'result' vectors must already have the size of the total variables&constraints in the system; the procedure will use the ChVariable offsets (that must be already updated) to know the indexes in result and vect.
Implements chrono::ChVariables.