/*!\file Numericalflux.c
 * \brief: implementation of the Numericalflux object
 */

/*Headers:*/
/*{{{*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#else
#error "Cannot compile with HAVE_CONFIG_H symbol! run configure first!"
#endif

#include <stdio.h>
#include <string.h>
#include "../../../EnumDefinitions/EnumDefinitions.h"
#include "../../../shared/shared.h"
#include "../../../include/include.h"
#include "../../classes.h"
/*}}}*/	

/*Load macros*/
#define NUMVERTICES_INTERNAL 4
#define NUMVERTICES_BOUNDARY 2

/*Numericalflux constructors and destructor*/
/*FUNCTION Numericalflux::Numericalflux(){{{*/
Numericalflux::Numericalflux(){
	this->inputs=NULL;
	this->parameters=NULL;
	this->helement=NULL;
	this->element=NULL;
	this->hnodes=NULL;
	this->nodes=NULL;
}
/*}}}*/
/*}}}*//*FUNCTION Numericalflux::Numericalflux(int id, int i, IoModel* iomodel, int analysis_type) {{{*/
Numericalflux::Numericalflux(int numericalflux_id,int i, IoModel* iomodel, int in_analysis_type){

	/* Intermediary */
	int  e1,e2;
	int  i1,i2;
	int  j;
	int  pos1,pos2,pos3,pos4;
	int  num_nodes;
	int  num_elems;

	/*numericalflux constructor data: */
	int   numericalflux_elem_ids[2];
	int   numericalflux_mparid;
	int   numericalflux_node_ids[4];
	int   numericalflux_type;

	int    numberofelements;

	/*Fetch parameters: */
	iomodel->Constant(&numberofelements,MeshNumberofelementsEnum);

	/* Get MatPar id */
	numericalflux_mparid=numberofelements+1; //matlab indexing

	/*First, see wether this is an internal or boundary edge (if e2=-1)*/
	if (iomodel->Data(MeshEdgesEnum)[4*i+3]==-1.){ //edges are [node1 node2 elem1 elem2]
		/* Boundary edge, only one element */
		e1=reCast<int>(iomodel->Data(MeshEdgesEnum)[4*i+2]);
		e2=reCast<int>(UNDEF);
		num_elems=1;
		num_nodes=2;
		numericalflux_type=BoundaryEnum;
		numericalflux_elem_ids[0]=e1;
	}
	else{
		/* internal edge: connected to 2 elements */
		e1=reCast<int>(iomodel->Data(MeshEdgesEnum)[4*i+2]);
		e2=reCast<int>(iomodel->Data(MeshEdgesEnum)[4*i+3]);
		num_elems=2;
		num_nodes=4;
		numericalflux_type=InternalEnum;
		numericalflux_elem_ids[0]=e1;
		numericalflux_elem_ids[1]=e2;
	}

	/*1: Get vertices ids*/
	i1=reCast<int>(iomodel->Data(MeshEdgesEnum)[4*i+0]);
	i2=reCast<int>(iomodel->Data(MeshEdgesEnum)[4*i+1]);

	if (numericalflux_type==InternalEnum){

		/*Now, we must get the nodes of the 4 nodes located on the edge*/

		/*2: Get the column where these ids are located in the index*/
		pos1=pos2=pos3=pos4=UNDEF;
		for(j=0;j<3;j++){
			if (iomodel->Data(MeshElementsEnum)[3*(e1-1)+j]==i1) pos1=j+1;
			if (iomodel->Data(MeshElementsEnum)[3*(e1-1)+j]==i2) pos2=j+1;
			if (iomodel->Data(MeshElementsEnum)[3*(e2-1)+j]==i1) pos3=j+1;
			if (iomodel->Data(MeshElementsEnum)[3*(e2-1)+j]==i2) pos4=j+1;
		}
		_assert_(pos1!=UNDEF && pos2!=UNDEF && pos3!=UNDEF && pos4!=UNDEF);

		/*3: We have the id of the elements and the position of the vertices in the index
		 * we can compute their dofs!*/
		numericalflux_node_ids[0]=iomodel->nodecounter+3*(e1-1)+pos1;
		numericalflux_node_ids[1]=iomodel->nodecounter+3*(e1-1)+pos2;
		numericalflux_node_ids[2]=iomodel->nodecounter+3*(e2-1)+pos3;
		numericalflux_node_ids[3]=iomodel->nodecounter+3*(e2-1)+pos4;
	}
	else{

		/*2: Get the column where these ids are located in the index*/
		pos1=pos2=UNDEF;
		for(j=0;j<3;j++){
			if (iomodel->Data(MeshElementsEnum)[3*(e1-1)+j]==i1) pos1=j+1;
			if (iomodel->Data(MeshElementsEnum)[3*(e1-1)+j]==i2) pos2=j+1;
		}
		_assert_(pos1!=UNDEF && pos2!=UNDEF);

		/*3: We have the id of the elements and the position of the vertices in the index
		 * we can compute their dofs!*/
		numericalflux_node_ids[0]=iomodel->nodecounter+3*(e1-1)+pos1;
		numericalflux_node_ids[1]=iomodel->nodecounter+3*(e1-1)+pos2;
	}

	/*Ok, we have everything to build the object: */
	this->id=numericalflux_id;
	this->analysis_type=in_analysis_type;

	/*Hooks: */
	this->hnodes  =new Hook(numericalflux_node_ids,num_nodes);
	this->helement=new Hook(numericalflux_elem_ids,1); // take only the first element for now

	//intialize  and add as many inputs per element as requested: 
	this->inputs=new Inputs();
	this->inputs->AddInput(new IntInput(TypeEnum,numericalflux_type));

	//this->parameters: we still can't point to it, it may not even exist. Configure will handle this.
	this->parameters=NULL;
	this->element=NULL;
	this->nodes=NULL;
}
/*}}}*/
/*FUNCTION Numericalflux::~Numericalflux(){{{*/
Numericalflux::~Numericalflux(){
	delete inputs;
	this->parameters=NULL;
	delete helement;
	delete hnodes;
}
/*}}}*/

/*Object virtual functions definitions:*/
/*FUNCTION Numericalflux::Echo {{{*/
void Numericalflux::Echo(void){
	_printLine_("Numericalflux:");
	_printLine_("   id: " << id);
	_printLine_("   analysis_type: " << EnumToStringx(analysis_type));
	hnodes->Echo();
	helement->Echo();
	_printLine_("   parameters: " << parameters);
	_printLine_("   inputs: " << inputs);
}
/*}}}*/
/*FUNCTION Numericalflux::DeepEcho {{{*/
void Numericalflux::DeepEcho(void){

	_printLine_("Numericalflux:");
	_printLine_("   id: " << id);
	_printLine_("   analysis_type: " << EnumToStringx(analysis_type));
	hnodes->DeepEcho();
	helement->DeepEcho();
	_printLine_("   parameters");
	if(parameters)
	 parameters->DeepEcho();
	else
	 _printLine_("      NULL");
	_printLine_("   inputs");
	inputs->DeepEcho();
	
}		
/*}}}*/
/*FUNCTION Numericalflux::Id {{{*/
int    Numericalflux::Id(void){
	return id;
}
/*}}}*/
/*FUNCTION Numericalflux::MyRank {{{*/
int    Numericalflux::MyRank(void){ 
	extern int my_rank;
	return my_rank; 
}
/*}}}*/
/*FUNCTION Numericalflux::ObjectEnum{{{*/
int Numericalflux::ObjectEnum(void){

	return NumericalfluxEnum;

}
/*}}}*/
/*FUNCTION Numericalflux::copy {{{*/
Object* Numericalflux::copy() {
	
	Numericalflux* numericalflux=NULL;

	numericalflux=new Numericalflux();

	/*copy fields: */
	numericalflux->id=this->id;
	numericalflux->analysis_type=this->analysis_type;
	if(this->inputs){
		numericalflux->inputs=(Inputs*)this->inputs->Copy();
	}
	else{
		numericalflux->inputs=new Inputs();
	}
	/*point parameters: */
	numericalflux->parameters=this->parameters;

	/*now deal with hooks and objects: */
	numericalflux->hnodes=(Hook*)this->hnodes->copy();
	numericalflux->helement=(Hook*)this->helement->copy();

	/*corresponding fields*/
	numericalflux->nodes  =(Node**)numericalflux->hnodes->deliverp();
	numericalflux->element=(Element*)numericalflux->helement->delivers();

	return numericalflux;
}
/*}}}*/

/*Load virtual functions definitions:*/
/*FUNCTION Numericalflux::Configure {{{*/
void  Numericalflux::Configure(Elements* elementsin,Loads* loadsin,Nodes* nodesin,Vertices* verticesin,Materials* materialsin,Parameters* parametersin){

	/*Take care of hooking up all objects for this element, ie links the objects in the hooks to their respective 
	 * datasets, using internal ids and offsets hidden in hooks: */
	hnodes->configure(nodesin);
	helement->configure(elementsin);

	/*Initialize hooked fields*/
	this->nodes  =(Node**)hnodes->deliverp();
	this->element=(Element*)helement->delivers();

	/*point parameters to real dataset: */
	this->parameters=parametersin;

}
/*}}}*/
/*FUNCTION Numericalflux::SetCurrentConfiguration {{{*/
void  Numericalflux::SetCurrentConfiguration(Elements* elementsin,Loads* loadsin,Nodes* nodesin,Vertices* verticesin,Materials* materialsin,Parameters* parametersin){

}
/*}}}*/
/*FUNCTION Numericalflux::CreateKMatrix {{{*/
void  Numericalflux::CreateKMatrix(Matrix* Kff, Matrix* Kfs){

	/*recover some parameters*/
	ElementMatrix* Ke=NULL;
	int analysis_type;
	this->parameters->FindParam(&analysis_type,AnalysisTypeEnum);

	/*Just branch to the correct element stiffness matrix generator, according to the type of analysis we are carrying out: */
	switch(analysis_type){
		case PrognosticAnalysisEnum:
			Ke=CreateKMatrixPrognostic();
			break;
		case BalancethicknessAnalysisEnum:
			Ke=CreateKMatrixBalancethickness();
			break;
		case AdjointBalancethicknessAnalysisEnum:
			Ke=CreateKMatrixAdjointBalancethickness();
			break;
		default:
			_error2_("analysis " << analysis_type << " (" << EnumToStringx(analysis_type) << ") not supported yet");
	}

	/*Add to global matrix*/
	if(Ke){
		Ke->AddToGlobal(Kff,Kfs);
		delete Ke;
	}

}
/*}}}*/
/*FUNCTION Numericalflux::CreatePVector {{{*/
void  Numericalflux::CreatePVector(Vector* pf){

	/*recover some parameters*/
	ElementVector* pe=NULL;
	int analysis_type;
	this->parameters->FindParam(&analysis_type,AnalysisTypeEnum);

	switch(analysis_type){
		case PrognosticAnalysisEnum:
			pe=CreatePVectorPrognostic();
			break;
		case BalancethicknessAnalysisEnum:
			pe=CreatePVectorBalancethickness();
			break;
		case AdjointBalancethicknessAnalysisEnum:
			pe=CreatePVectorAdjointBalancethickness();
			break;
		default:
			_error2_("analysis " << analysis_type << " (" << EnumToStringx(analysis_type) << ") not supported yet");
	}

	/*Add to global matrix*/
	if(pe){
		pe->AddToGlobal(pf);
		delete pe;
	}

}
/*}}}*/
/*FUNCTION Numericalflux::PenaltyCreateKMatrix {{{*/
void  Numericalflux::PenaltyCreateKMatrix(Matrix* Kff, Matrix* Kfs,IssmDouble kmax){

	/*No stiffness loads applied, do nothing: */
	return;

}
/*}}}*/
/*FUNCTION Numericalflux::PenaltyCreatePVector{{{*/
void  Numericalflux::PenaltyCreatePVector(Vector* pf,IssmDouble kmax){

	/*No penalty loads applied, do nothing: */
	return;

}
/*}}}*/
/*FUNCTION Numericalflux::InAnalysis{{{*/
bool Numericalflux::InAnalysis(int in_analysis_type){
	if (in_analysis_type==this->analysis_type) return true;
	else return false;
}
/*}}}*/

/*Numericalflux management*/
/*FUNCTION Numericalflux::CreateKMatrixPrognostic{{{*/
ElementMatrix* Numericalflux::CreateKMatrixPrognostic(void){

	int type;
	inputs->GetInputValue(&type,TypeEnum);

	switch(type){
		case InternalEnum:
			return CreateKMatrixPrognosticInternal();
		case BoundaryEnum:
			return CreateKMatrixPrognosticBoundary();
		default:
			_error2_("type not supported yet");
	}
}
/*}}}*/
/*FUNCTION Numericalflux::CreateKMatrixPrognosticInternal {{{*/
ElementMatrix* Numericalflux::CreateKMatrixPrognosticInternal(void){

	/* constants*/
	const int numdof=NDOF1*NUMVERTICES_INTERNAL;

	/* Intermediaries*/
	int        i,j,ig,index1,index2;
	IssmDouble     DL1,DL2,Jdet,dt,vx,vy,UdotN;
	IssmDouble     xyz_list[NUMVERTICES_INTERNAL][3];
	IssmDouble     normal[2];
	IssmDouble     B[numdof];
	IssmDouble     Bprime[numdof];
	IssmDouble     Ke_g1[numdof][numdof];
	IssmDouble     Ke_g2[numdof][numdof];
	GaussTria *gauss;

	/*Initialize Element matrix and return if necessary*/
	Tria*  tria=(Tria*)element;
	if(tria->IsOnWater()) return NULL;
	ElementMatrix* Ke=new ElementMatrix(nodes,NUMVERTICES_INTERNAL,this->parameters);

	/*Retrieve all inputs and parameters*/
	GetVerticesCoordinates(&xyz_list[0][0], nodes,NUMVERTICES_INTERNAL);
	parameters->FindParam(&dt,TimesteppingTimeStepEnum);
	Input* vxaverage_input=tria->inputs->GetInput(VxEnum);
	Input* vyaverage_input=tria->inputs->GetInput(VyEnum);
	GetNormal(&normal[0],xyz_list);

	/* Start  looping on the number of gaussian points: */
	index1=tria->GetNodeIndex(nodes[0]);
	index2=tria->GetNodeIndex(nodes[1]);
	gauss=new GaussTria(index1,index2,2);
	for(ig=gauss->begin();ig<gauss->end();ig++){

		gauss->GaussPoint(ig);

		tria->GetSegmentBFlux(&B[0],gauss,index1,index2);
		tria->GetSegmentBprimeFlux(&Bprime[0],gauss,index1,index2);

		vxaverage_input->GetInputValue(&vx,gauss);
		vyaverage_input->GetInputValue(&vy,gauss);
		UdotN=vx*normal[0]+vy*normal[1];
		tria->GetSegmentJacobianDeterminant(&Jdet,&xyz_list[0][0],gauss);
		DL1=gauss->weight*Jdet*dt*UdotN/2;
		DL2=gauss->weight*Jdet*dt*fabs(UdotN)/2;

		TripleMultiply(&B[0],1,numdof,1,
					&DL1,1,1,0,
					&Bprime[0],1,numdof,0,
					&Ke_g1[0][0],0);
		TripleMultiply(&B[0],1,numdof,1,
					&DL2,1,1,0,
					&B[0],1,numdof,0,
					&Ke_g2[0][0],0);

		for(i=0;i<numdof;i++) for(j=0;j<numdof;j++) Ke->values[i*numdof+j]+=Ke_g1[i][j];
		for(i=0;i<numdof;i++) for(j=0;j<numdof;j++) Ke->values[i*numdof+j]+=Ke_g2[i][j];
	}
	
	/*Clean up and return*/
	delete gauss;
	return Ke;
}
/*}}}*/
/*FUNCTION Numericalflux::CreateKMatrixPrognosticBoundary {{{*/
ElementMatrix* Numericalflux::CreateKMatrixPrognosticBoundary(void){

	/* constants*/
	const int numdof=NDOF1*NUMVERTICES_BOUNDARY;

	/* Intermediaries*/
	int        i,j,ig,index1,index2;
	IssmDouble     DL,Jdet,dt,vx,vy,mean_vx,mean_vy,UdotN;
	IssmDouble     xyz_list[NUMVERTICES_BOUNDARY][3];
	IssmDouble     normal[2];
	IssmDouble     L[numdof];
	IssmDouble     Ke_g[numdof][numdof];
	GaussTria *gauss;

	/*Initialize Element matrix and return if necessary*/
	ElementMatrix* Ke = NULL;
	Tria*  tria=(Tria*)element;
	if(tria->IsOnWater()) return NULL;

	/*Retrieve all inputs and parameters*/
	GetVerticesCoordinates(&xyz_list[0][0],nodes,NUMVERTICES_BOUNDARY);
	parameters->FindParam(&dt,TimesteppingTimeStepEnum);
	Input* vxaverage_input=tria->inputs->GetInput(VxEnum); _assert_(vxaverage_input);
	Input* vyaverage_input=tria->inputs->GetInput(VyEnum); _assert_(vyaverage_input);
	GetNormal(&normal[0],xyz_list);

	/*Check wether it is an inflow or outflow BC (0 is the middle of the segment)*/
	index1=tria->GetNodeIndex(nodes[0]);
	index2=tria->GetNodeIndex(nodes[1]);

	gauss=new GaussTria();
	gauss->GaussEdgeCenter(index1,index2);
	vxaverage_input->GetInputValue(&mean_vx,gauss);
	vyaverage_input->GetInputValue(&mean_vy,gauss);
	delete gauss;

	UdotN=mean_vx*normal[0]+mean_vy*normal[1];
	if (UdotN<=0){
		return NULL; /*(u,n)<0 -> inflow, PenaltyCreatePVector will take care of it*/
	}
	else{
		Ke=new ElementMatrix(nodes,NUMVERTICES_BOUNDARY,this->parameters);
	}

	/* Start  looping on the number of gaussian points: */
	gauss=new GaussTria(index1,index2,2);
	for(ig=gauss->begin();ig<gauss->end();ig++){

		gauss->GaussPoint(ig);

		tria->GetSegmentNodalFunctions(&L[0],gauss,index1,index2);

		vxaverage_input->GetInputValue(&vx,gauss);
		vyaverage_input->GetInputValue(&vy,gauss);
		UdotN=vx*normal[0]+vy*normal[1];
		tria->GetSegmentJacobianDeterminant(&Jdet,&xyz_list[0][0],gauss);
		DL=gauss->weight*Jdet*dt*UdotN;

		TripleMultiply(&L[0],1,numdof,1,
					&DL,1,1,0,
					&L[0],1,numdof,0,
					&Ke_g[0][0],0);

		for(i=0;i<numdof;i++) for(j=0;j<numdof;j++) Ke->values[i*numdof+j]+=Ke_g[i][j];
	} 

	/*Clean up and return*/
	delete gauss;
	return Ke;
}
/*}}}*/
/*FUNCTION Numericalflux::CreateKMatrixBalancethickness{{{*/
ElementMatrix* Numericalflux::CreateKMatrixBalancethickness(void){

	int type;
	inputs->GetInputValue(&type,TypeEnum);

	switch(type){
		case InternalEnum:
			return CreateKMatrixBalancethicknessInternal();
		case BoundaryEnum:
			return CreateKMatrixBalancethicknessBoundary();
		default:
			_error2_("type not supported yet");
	}
}
/*}}}*/
/*FUNCTION Numericalflux::CreateKMatrixBalancethicknessInternal {{{*/
ElementMatrix* Numericalflux::CreateKMatrixBalancethicknessInternal(void){

	/* constants*/
	const int numdof=NDOF1*NUMVERTICES_INTERNAL;

	/* Intermediaries*/
	int        i,j,ig,index1,index2;
	IssmDouble     DL1,DL2,Jdet,vx,vy,UdotN;
	IssmDouble     xyz_list[NUMVERTICES_INTERNAL][3];
	IssmDouble     normal[2];
	IssmDouble     B[numdof];
	IssmDouble     Bprime[numdof];
	IssmDouble     Ke_g1[numdof][numdof];
	IssmDouble     Ke_g2[numdof][numdof];
	GaussTria *gauss;

	/*Initialize Element matrix and return if necessary*/
	Tria*  tria=(Tria*)element;
	if(tria->IsOnWater()) return NULL;
	ElementMatrix* Ke=new ElementMatrix(nodes,NUMVERTICES_INTERNAL,this->parameters);

	/*Retrieve all inputs and parameters*/
	GetVerticesCoordinates(&xyz_list[0][0], nodes,NUMVERTICES_INTERNAL);
	Input* vxaverage_input=tria->inputs->GetInput(VxEnum);
	Input* vyaverage_input=tria->inputs->GetInput(VyEnum);
	GetNormal(&normal[0],xyz_list);

	/* Start  looping on the number of gaussian points: */
	index1=tria->GetNodeIndex(nodes[0]);
	index2=tria->GetNodeIndex(nodes[1]);
	gauss=new GaussTria(index1,index2,2);
	for(ig=gauss->begin();ig<gauss->end();ig++){

		gauss->GaussPoint(ig);

		tria->GetSegmentBFlux(&B[0],gauss,index1,index2);
		tria->GetSegmentBprimeFlux(&Bprime[0],gauss,index1,index2);

		vxaverage_input->GetInputValue(&vx,gauss);
		vyaverage_input->GetInputValue(&vy,gauss);
		UdotN=vx*normal[0]+vy*normal[1];
		tria->GetSegmentJacobianDeterminant(&Jdet,&xyz_list[0][0],gauss);
		DL1=gauss->weight*Jdet*UdotN/2;
		DL2=gauss->weight*Jdet*fabs(UdotN)/2;

		TripleMultiply(&B[0],1,numdof,1,
					&DL1,1,1,0,
					&Bprime[0],1,numdof,0,
					&Ke_g1[0][0],0);
		TripleMultiply(&B[0],1,numdof,1,
					&DL2,1,1,0,
					&B[0],1,numdof,0,
					&Ke_g2[0][0],0);

		for(i=0;i<numdof;i++) for(j=0;j<numdof;j++) Ke->values[i*numdof+j]+=Ke_g1[i][j];
		for(i=0;i<numdof;i++) for(j=0;j<numdof;j++) Ke->values[i*numdof+j]+=Ke_g2[i][j];
	}

	/*Clean up and return*/
	delete gauss;
	return Ke;
}
/*}}}*/
/*FUNCTION Numericalflux::CreateKMatrixBalancethicknessBoundary {{{*/
ElementMatrix* Numericalflux::CreateKMatrixBalancethicknessBoundary(void){

	/* constants*/
	const int numdof=NDOF1*NUMVERTICES_BOUNDARY;

	/* Intermediaries*/
	int        i,j,ig,index1,index2;
	IssmDouble     DL,Jdet,vx,vy,mean_vx,mean_vy,UdotN;
	IssmDouble     xyz_list[NUMVERTICES_BOUNDARY][3];
	IssmDouble     normal[2];
	IssmDouble     L[numdof];
	IssmDouble     Ke_g[numdof][numdof];
	GaussTria *gauss;

	/*Initialize Element matrix and return if necessary*/
	ElementMatrix* Ke = NULL;
	Tria*  tria=(Tria*)element;
	if(tria->IsOnWater()) return NULL;

	/*Retrieve all inputs and parameters*/
	GetVerticesCoordinates(&xyz_list[0][0],nodes,NUMVERTICES_BOUNDARY);
	Input* vxaverage_input=tria->inputs->GetInput(VxEnum);
	Input* vyaverage_input=tria->inputs->GetInput(VyEnum);
	GetNormal(&normal[0],xyz_list);

	/*Check wether it is an inflow or outflow BC (0 is the middle of the segment)*/
	index1=tria->GetNodeIndex(nodes[0]);
	index2=tria->GetNodeIndex(nodes[1]);

	gauss=new GaussTria();
	gauss->GaussEdgeCenter(index1,index2);
	vxaverage_input->GetInputValue(&mean_vx,gauss);
	vyaverage_input->GetInputValue(&mean_vy,gauss);
	delete gauss;

	UdotN=mean_vx*normal[0]+mean_vy*normal[1];
	if (UdotN<=0){
		return NULL; /*(u,n)<0 -> inflow, PenaltyCreatePVector will take care of it*/
	}
	else{
		Ke=new ElementMatrix(nodes,NUMVERTICES_BOUNDARY,this->parameters);
	}

	/* Start  looping on the number of gaussian points: */
	gauss=new GaussTria(index1,index2,2);
	for(ig=gauss->begin();ig<gauss->end();ig++){

		gauss->GaussPoint(ig);

		tria->GetSegmentNodalFunctions(&L[0],gauss,index1,index2);

		vxaverage_input->GetInputValue(&vx,gauss);
		vyaverage_input->GetInputValue(&vy,gauss);
		UdotN=vx*normal[0]+vy*normal[1];
		tria->GetSegmentJacobianDeterminant(&Jdet,&xyz_list[0][0],gauss);
		DL=gauss->weight*Jdet*UdotN;

		TripleMultiply(&L[0],1,numdof,1,
					&DL,1,1,0,
					&L[0],1,numdof,0,
					&Ke_g[0][0],0);

		for(i=0;i<numdof;i++) for(j=0;j<numdof;j++) Ke->values[i*numdof+j]+=Ke_g[i][j];
	} 

	/*Clean up and return*/
	delete gauss;
	return Ke;
}
/*}}}*/
/*FUNCTION Numericalflux::CreateKMatrixAdjointBalancethickness{{{*/
ElementMatrix* Numericalflux::CreateKMatrixAdjointBalancethickness(void){

	int type;
	inputs->GetInputValue(&type,TypeEnum);

	switch(type){
		case InternalEnum:
			return CreateKMatrixAdjointBalancethicknessInternal();
		case BoundaryEnum:
			return CreateKMatrixAdjointBalancethicknessBoundary();
		default:
			_error2_("type not supported yet");
	}
}
/*}}}*/
/*FUNCTION Numericalflux::CreateKMatrixAdjointBalancethicknessInternal {{{*/
ElementMatrix* Numericalflux::CreateKMatrixAdjointBalancethicknessInternal(void){

	ElementMatrix* Ke=CreateKMatrixBalancethicknessInternal();
	if (Ke) Ke->Transpose();
	return Ke;
}
/*}}}*/
/*FUNCTION Numericalflux::CreateKMatrixAdjointBalancethicknessBoundary {{{*/
ElementMatrix* Numericalflux::CreateKMatrixAdjointBalancethicknessBoundary(void){

	ElementMatrix* Ke=CreateKMatrixBalancethicknessBoundary();
	if(Ke) Ke->Transpose();
	return Ke;
}
/*}}}*/
/*FUNCTION Numericalflux::CreatePVectorPrognostic{{{*/
ElementVector* Numericalflux::CreatePVectorPrognostic(void){

	int type;
	inputs->GetInputValue(&type,TypeEnum);

	switch(type){
		case InternalEnum:
			return CreatePVectorPrognosticInternal();
		case BoundaryEnum:
			return CreatePVectorPrognosticBoundary();
		default:
			_error2_("type not supported yet");
	}
}
/*}}}*/
/*FUNCTION Numericalflux::CreatePVectorPrognosticInternal{{{*/
ElementVector* Numericalflux::CreatePVectorPrognosticInternal(void){

	/*Nothing added to PVector*/
	return NULL;

}
/*}}}*/
/*FUNCTION Numericalflux::CreatePVectorPrognosticBoundary{{{*/
ElementVector* Numericalflux::CreatePVectorPrognosticBoundary(void){

	/* constants*/
	const int numdof=NDOF1*NUMVERTICES_BOUNDARY;

	/* Intermediaries*/
	int        i,j,ig,index1,index2;
	IssmDouble     DL,Jdet,dt,vx,vy,mean_vx,mean_vy,UdotN,thickness;
	IssmDouble     xyz_list[NUMVERTICES_BOUNDARY][3];
	IssmDouble     normal[2];
	IssmDouble     L[numdof];
	GaussTria *gauss;

	/*Initialize Load Vector and return if necessary*/
	ElementVector* pe = NULL;
	Tria*  tria=(Tria*)element;
	if(tria->IsOnWater()) return NULL;

	/*Retrieve all inputs and parameters*/
	GetVerticesCoordinates(&xyz_list[0][0],nodes,NUMVERTICES_BOUNDARY);
	parameters->FindParam(&dt,TimesteppingTimeStepEnum);
	Input* vxaverage_input   =tria->inputs->GetInput(VxEnum);                     _assert_(vxaverage_input); 
	Input* vyaverage_input   =tria->inputs->GetInput(VyEnum);                     _assert_(vyaverage_input);
	Input* spcthickness_input=tria->inputs->GetInput(PrognosticSpcthicknessEnum); _assert_(spcthickness_input);
	GetNormal(&normal[0],xyz_list);

	/*Check wether it is an inflow or outflow BC (0 is the middle of the segment)*/
	index1=tria->GetNodeIndex(nodes[0]);
	index2=tria->GetNodeIndex(nodes[1]);

	gauss=new GaussTria();
	gauss->GaussEdgeCenter(index1,index2);
	vxaverage_input->GetInputValue(&mean_vx,gauss);
	vyaverage_input->GetInputValue(&mean_vy,gauss);
	delete gauss;

	UdotN=mean_vx*normal[0]+mean_vy*normal[1];
	if (UdotN>0){
		return NULL; /*(u,n)>0 -> outflow, PenaltyCreateKMatrix will take care of it*/
	}
	else{
		pe=new ElementVector(nodes,NUMVERTICES_BOUNDARY,this->parameters);
	}

	/* Start  looping on the number of gaussian points: */
	gauss=new GaussTria(index1,index2,2);
	for(ig=gauss->begin();ig<gauss->end();ig++){

		gauss->GaussPoint(ig);

		tria->GetSegmentNodalFunctions(&L[0],gauss,index1,index2);

		vxaverage_input->GetInputValue(&vx,gauss);
		vyaverage_input->GetInputValue(&vy,gauss);
		spcthickness_input->GetInputValue(&thickness,gauss);
		if(xIsNan<IssmDouble>(thickness)) _error2_("Cannot weakly apply constraint because NaN was provided");

		UdotN=vx*normal[0]+vy*normal[1];
		tria->GetSegmentJacobianDeterminant(&Jdet,&xyz_list[0][0],gauss);
		DL= - gauss->weight*Jdet*dt*UdotN*thickness;

		for(i=0;i<numdof;i++) pe->values[i] += DL*L[i];
	}

	/*Clean up and return*/
	delete gauss;
	return pe;
}
/*}}}*/
/*FUNCTION Numericalflux::CreatePVectorBalancethickness{{{*/
ElementVector* Numericalflux::CreatePVectorBalancethickness(void){

	int type;
	inputs->GetInputValue(&type,TypeEnum);

	switch(type){
		case InternalEnum:
			return CreatePVectorBalancethicknessInternal();
		case BoundaryEnum:
			return CreatePVectorBalancethicknessBoundary();
		default:
			_error2_("type not supported yet");
	}
}
/*}}}*/
/*FUNCTION Numericalflux::CreatePVectorBalancethicknessInternal{{{*/
ElementVector* Numericalflux::CreatePVectorBalancethicknessInternal(void){

	/*Nothing added to PVector*/
	return NULL;

}
/*}}}*/
/*FUNCTION Numericalflux::CreatePVectorBalancethicknessBoundary{{{*/
ElementVector* Numericalflux::CreatePVectorBalancethicknessBoundary(void){

	/* constants*/
	const int numdof=NDOF1*NUMVERTICES_BOUNDARY;

	/* Intermediaries*/
	int        i,j,ig,index1,index2;
	IssmDouble     DL,Jdet,vx,vy,mean_vx,mean_vy,UdotN,thickness;
	IssmDouble     xyz_list[NUMVERTICES_BOUNDARY][3];
	IssmDouble     normal[2];
	IssmDouble     L[numdof];
	GaussTria *gauss;

	/*Initialize Load Vector and return if necessary*/
	ElementVector* pe = NULL;
	Tria*  tria=(Tria*)element;
	if(tria->IsOnWater()) return NULL;

	/*Retrieve all inputs and parameters*/
	GetVerticesCoordinates(&xyz_list[0][0],nodes,NUMVERTICES_BOUNDARY);
	Input* vxaverage_input=tria->inputs->GetInput(VxEnum); _assert_(vxaverage_input); 
	Input* vyaverage_input=tria->inputs->GetInput(VyEnum); _assert_(vyaverage_input);
	Input* thickness_input=tria->inputs->GetInput(ThicknessEnum); _assert_(thickness_input);
	GetNormal(&normal[0],xyz_list);

	/*Check wether it is an inflow or outflow BC (0 is the middle of the segment)*/
	index1=tria->GetNodeIndex(nodes[0]);
	index2=tria->GetNodeIndex(nodes[1]);

	gauss=new GaussTria();
	gauss->GaussEdgeCenter(index1,index2);
	vxaverage_input->GetInputValue(&mean_vx,gauss);
	vyaverage_input->GetInputValue(&mean_vy,gauss);
	delete gauss;
	UdotN=mean_vx*normal[0]+mean_vy*normal[1];
	if (UdotN>0){
		return NULL; /*(u,n)>0 -> outflow, PenaltyCreateKMatrix will take care of it*/
	}
	else{
		pe=new ElementVector(nodes,NUMVERTICES_BOUNDARY,this->parameters);
	}

	/* Start  looping on the number of gaussian points: */
	gauss=new GaussTria(index1,index2,2);
	for(ig=gauss->begin();ig<gauss->end();ig++){

		gauss->GaussPoint(ig);

		tria->GetSegmentNodalFunctions(&L[0],gauss,index1,index2);

		vxaverage_input->GetInputValue(&vx,gauss);
		vyaverage_input->GetInputValue(&vy,gauss);
		thickness_input->GetInputValue(&thickness,gauss);

		UdotN=vx*normal[0]+vy*normal[1];
		tria->GetSegmentJacobianDeterminant(&Jdet,&xyz_list[0][0],gauss);
		DL= - gauss->weight*Jdet*UdotN*thickness;

		for(i=0;i<numdof;i++) pe->values[i] += DL*L[i];
	}

	/*Clean up and return*/
	delete gauss;
	return pe;
}
/*}}}*/
/*FUNCTION Numericalflux::CreatePVectorAdjointBalancethickness{{{*/
ElementVector* Numericalflux::CreatePVectorAdjointBalancethickness(void){

	/*No PVector for the Adjoint*/
	return NULL;
}
/*}}}*/
/*FUNCTION Numericalflux::GetNormal {{{*/
void Numericalflux:: GetNormal(IssmDouble* normal,IssmDouble xyz_list[4][3]){

	/*Build unit outward pointing vector*/
	IssmDouble vector[2];
	IssmDouble norm;

	vector[0]=xyz_list[1][0] - xyz_list[0][0];
	vector[1]=xyz_list[1][1] - xyz_list[0][1];

	norm=sqrt(pow(vector[0],2.0)+pow(vector[1],2.0));

	normal[0]= + vector[1]/norm;
	normal[1]= - vector[0]/norm;
}
/*}}}*/
