ShallowWater1DJacobian.c

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#include <mathfunctions.h>
#include <matmult_native.h>
#include <physicalmodels/shallowwater1d.h>

int ShallowWater1DJacobian(
                    double  *Jac, 
                    double  *u,   
                    void    *p,   
                    int     dir,  
                    int     nvars,
                    int     upw   
                   )
{
  ShallowWater1D  *param = (ShallowWater1D*) p;
  static double   R[_MODEL_NVARS_*_MODEL_NVARS_], D[_MODEL_NVARS_*_MODEL_NVARS_], 
                  L[_MODEL_NVARS_*_MODEL_NVARS_], DL[_MODEL_NVARS_*_MODEL_NVARS_];

  /* get the eigenvalues and left,right eigenvectors */
  _ShallowWater1DEigenvalues_      (u,D,param,0);
  _ShallowWater1DLeftEigenvectors_ (u,L,param,0);
  _ShallowWater1DRightEigenvectors_(u,R,param,0);

  int aupw = absolute(upw), k;
  k = 0; D[k] = absolute( (1-aupw)*D[k] + 0.5*aupw*(1+upw)*max(0,D[k]) + 0.5*aupw*(1-upw)*min(0,D[k]) );
  k = 3; D[k] = absolute( (1-aupw)*D[k] + 0.5*aupw*(1+upw)*max(0,D[k]) + 0.5*aupw*(1-upw)*min(0,D[k]) );

  MatMult2(2,DL,D,L);
  MatMult2(2,Jac,R,DL);

  return(0);
}