chrono::ChLoadCustom Class Reference


Loads acting on a single ChLoadable item.

Differently form ChLoad, this does not use the ChLoader interface, so one must inherit from this and implement ComputeQ() directly. The ComputeQ() must write the generalized forces Q into the "load_Q" vector of this object.

#include <ChLoad.h>

Inheritance diagram for chrono::ChLoadCustom:
Collaboration diagram for chrono::ChLoadCustom:

Public Member Functions

 ChLoadCustom (std::shared_ptr< ChLoadable > mloadable)
virtual int LoadGet_ndof_x () override
 Gets the number of DOFs affected by this load (position part)
virtual int LoadGet_ndof_w () override
 Gets the number of DOFs affected by this load (speed part)
virtual void LoadGetStateBlock_x (ChState &mD) override
 Gets all the current DOFs packed in a single vector (position part)
virtual void LoadGetStateBlock_w (ChStateDelta &mD) override
 Gets all the current DOFs packed in a single vector (speed part)
virtual void LoadStateIncrement (const ChState &x, const ChStateDelta &dw, ChState &x_new) override
 Increment a packed state (ex. More...
virtual int LoadGet_field_ncoords () override
 Number of coordinates in the interpolated field, ex=3 for a tetrahedron finite element or a cable, = 1 for a thermal problem, etc.
virtual void ComputeJacobian (ChState *state_x, ChStateDelta *state_w, ChMatrixRef mK, ChMatrixRef mR, ChMatrixRef mM) override
 Compute jacobians (default fallback). More...
virtual void LoadIntLoadResidual_F (ChVectorDynamic<> &R, const double c) override
 Adds the internal loads Q (pasted at global nodes offsets) into a global vector R, multiplied by a scaling factor c, as R += forces * c.
virtual void CreateJacobianMatrices () override
 Create the jacobian loads if needed, and also set the ChVariables referenced by the sparse KRM block.
virtual ChVectorDynamicGetQ ()
 Access the generalized load vector Q.
- Public Member Functions inherited from chrono::ChLoadBase
virtual void ComputeQ (ChState *state_x, ChStateDelta *state_w)=0
 Compute Q, the generalized load(s). More...
ChLoadJacobiansGetJacobians ()
 Access the jacobians (if any, i.e. if this is a stiff load)
virtual void Update (double time)
 Update: this is called at least at each time step. More...
virtual bool IsStiff ()=0
 Report if this is load is stiff. More...
virtual void InjectKRMmatrices (ChSystemDescriptor &mdescriptor)
 Tell to a system descriptor that there are item(s) of type ChKblock in this object (for further passing it to a solver) Basically does nothing, but inherited classes must specialize this.
virtual void KRMmatricesLoad (double Kfactor, double Rfactor, double Mfactor)
 Adds the current stiffness K and damping R and mass M matrices in encapsulated ChKblock item(s), if any. More...
- Public Member Functions inherited from chrono::ChObj
 ChObj (const ChObj &other)
virtual ChObjClone () const =0
 "Virtual" copy constructor. More...
int GetIdentifier () const
 Gets the numerical identifier of the object.
void SetIdentifier (int id)
 Sets the numerical identifier of the object.
double GetChTime () const
 Gets the simulation time of this object.
void SetChTime (double m_time)
 Sets the simulation time of this object.
const char * GetName () const
 Gets the name of the object as C Ascii null-terminated string -for reading only!
void SetName (const char myname[])
 Sets the name of this object, as ascii string.
std::string GetNameString () const
 Gets the name of the object as C Ascii null-terminated string.
void SetNameString (const std::string &myname)
 Sets the name of this object, as std::string.
void MFlagsSetAllOFF (int &mflag)
void MFlagsSetAllON (int &mflag)
void MFlagSetON (int &mflag, int mask)
void MFlagSetOFF (int &mflag, int mask)
int MFlagGet (int &mflag, int mask)
virtual void ArchiveOUT (ChArchiveOut &marchive)
 Method to allow serialization of transient data to archives.
virtual void ArchiveIN (ChArchiveIn &marchive)
 Method to allow de-serialization of transient data from archives.
virtual std::string & ArchiveContainerName ()

Public Attributes

std::shared_ptr< ChLoadableloadable
ChVectorDynamic load_Q

Additional Inherited Members

- Protected Attributes inherited from chrono::ChLoadBase
- Protected Attributes inherited from chrono::ChObj
double ChTime
 the time of simulation for the object

Member Function Documentation

◆ ComputeJacobian()

void chrono::ChLoadCustom::ComputeJacobian ( ChState state_x,
ChStateDelta state_w,
ChMatrixRef  mK,
ChMatrixRef  mR,
ChMatrixRef  mM 

Compute jacobians (default fallback).

Uses a numerical differentiation for computing K, R, M jacobians, if stiff load. If possible, override this with an analytical jacobian. Compute the K=-dQ/dx, R=-dQ/dv , M=-dQ/da jacobians. Called automatically at each Update().

state_xstate position to evaluate jacobians
state_wstate speed to evaluate jacobians
mKresult dQ/dx
mRresult dQ/dv
mMresult dQ/da

Implements chrono::ChLoadBase.

◆ LoadStateIncrement()

void chrono::ChLoadCustom::LoadStateIncrement ( const ChState x,
const ChStateDelta dw,
ChState x_new 

Increment a packed state (ex.

as obtained by LoadGetStateBlock_x()) by a given packed state-delta. Compute: x_new = x + dw. Ex. this is called by the BDF numerical differentiation routine that computes jacobian in the default ComputeJacobian() fallback, if not overriding ComputeJacobian() with an analytical form.

Implements chrono::ChLoadBase.

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