IncrementalIntegrator


# IncrementalIntegrator

#include <analysis/integrator/IncrementalIntegrator.h>

class IncrementalIntegrator: public Integrator

MovableObject
Integrator


IncrementalIntegrator is an abstract class. A subclass of it is used when performing a static or transient analysis using an incremental displacement approach. Subclasses of IncrementalIntegrators provide methods informing the FE_Element and DOF_Group objects how to build the tangent and residual matrices and vectors. They also provide the method for updating the response quantities at the DOFs with appropriate values; these values being some function of the solution to the linear system of equations.

// Constructor


// Destructor


// Public Methods






// Public Method added for Domain Decomposition


// Protected Methods




The integer classTag is passed to the Integrator classes constructor. Pointers to the AnalysisModel and LinearSOE are set to \(0\).


Does nothing.


Invoked by the Analysis object to set up the links the IncrementalIntegrator objects needs to perform its operations. Sets the pointers to the AnalysisModel and LinearSOE objects to point to theAnalaysisModel and theSOE.

virtual int formTangent(void);

Invoked to form the structure tangent matrix. The method first loops over all the FE_Elements in the AnalysisModel telling them to form their tangent and then it loops over the FE_Elements again adding the tangent to the LinearSOE objects A matrix. It performs the following:

while ̄ while w̄hile ̄ FE_EleIter &theEles = theAnalysisModel.getFEs();
theSOE.zeroA();
while((elePtr = theEles1()) \(\neq\) 0)
if (theSOE.addA(elePtr-\(>\)getTangent(this), elePtr-\(>\)getID(), \(1.0\)) \(<\) 0)
return \(-1\);

Returns \(0\) if successful, otherwise an error message is printed an a \(-1\) is returned if setLinks() has not been called, or \(-2\) if failure to add an FE_Elements tangent to the LinearSOE. The two loops are introduced to allow for efficient parallel programming. THIS MAY CHANGE TO REDUCE MEMORY DEMANDS.

virtual int formUnbalance(void);

Invoked to form the unbalance. The method fist zeros out the \(B\) vector of the LinearSOE object and then invokes formElementResidual() and formNodalUnbalance() on itself.

while ̄ while w̄hile ̄ theSOE.zeroB();
this-\(>\)fromElementResidual();
this-\(>\)formNodalUnbalance()

If an error occurs in either of these two methods or if setLinks() has not been called, an error message is printed and a negative number is returned. Returns \(0\) if successful.

To inform the FE_Element how to build its tangent matrix for addition to the system of equations. The subclasses must provide the implementation of this method.

virtual int formEleResidual(FE_Element \*theEle) =0;

To inform the FE_Element how to build its residual vector for addition to the system of equations. The subclasses must provide the implementation of this method.

virtual int formNodTangent(DOF_Group \*theDof) =0;

To inform the DOF_Group how to build its tangent matrix for addition to the system of equations. The subclasses must provide the implementation of this method. This is required in transient analysis as th Node objects have mass. THIS MAY CHANGE.

virtual int formNodUnbalance(DOF_Group \*theDof) =0;

To inform the DOF_Group how to build its residual vector for addition to the system of equations. The subclasses must provide the implementation of this method.

virtual int update(const Vector &$\Delta U$) =0;

When invoked causes the integrator object to update the DOF_Group responses with the appropriate values based on the computed solution to the system of equation object. The subclasses must provide an implementation of this method.

virtual int commit(void) =0;

Invoked by the SolutionAlgorithm to inform the Integrator that current state of domain is on solution path. Returns the result of invoking commitDomain() on the AnalysisModel object associated with the Integrator.


Returns in result values for the last solution to the system of equation object whose location in the solution vector is given by id. For a location specified by a negative integer in id 0.0 will be returned in result. Returns a \(0\) if successful, a warning message and a negative number is returned if an error occurs. \(-1\) if setSize() has not been called and a \(-2\) if location in id is greater than \(order-1\) of \(b\) vector.


A const member function which returns a pointer to the LinearSOE associated with the IncrementalIntegrator object, i.e. theSOE passed in setLinks().

AnalysisModel \*getAnalysisModelPtr(void) const;

A const member function which returns a pointer to the AnalysisModel associated with the IncrementalIntegrator object, i.e. theModel passed in setLinks().

virtual int formNodalUnbalance(void);

The method first loops over all the DOF_Group objects telling them to form their unbalance and then adds this Vector to the \(b\) vector of the LinearSOE object, i.e. it performs the following:

while ̄ while w̄hile ̄ DOF_EleIter &theDofs = theAnalysisModel.getDOFs();
theSOE.zeroB();
while((dofPtr = theDofs()) \(\neq\) 0)
theSOE.addB(dofPtr-\(>\)getUnbalance(theIntegrator), dofPtr-\(>\)getID())

Returns \(0\) if successful, otherwise a negative number is returned and a warning message is printed if an error occurred. Note, no test is made to ensure setLinks() has been invoked.

virtual int formElementResidual(void);

Invoked to form residual vector (the C vector in theSOE). The method iterates twice over the FE_elements in the AnalysisModel, the first time telling the FE_Elements top form their residual and the second time to add this residual to the LinearSOE objects \(b\) vector, i.e. it performs the following:

while ̄ while w̄hile ̄ FE_EleIter &theEles = theAnalysisModel.getFEs();
while((elePtr = theEles()) \(\neq\) 0) {
theSOE.addA(elePtr-\(>\)getResidual(this), elePtr-\(>\)getID())

Returns \(0\) if successful, otherwise a warning message is printed and a negative number is returned if an error occurs. Note, no test is made to ensure setLinks() has been invoked.

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