/*
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   SLEPc - Scalable Library for Eigenvalue Problem Computations
   Copyright (c) 2002-2020, Universitat Politecnica de Valencia, Spain

   This file is part of SLEPc.
   SLEPc is distributed under a 2-clause BSD license (see LICENSE).
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*/

static char help[] = "Test EPS interface functions.\n\n";

#include <slepceps.h>

int main(int argc,char **argv)
{
  Mat                A,B;         /* problem matrix */
  EPS                eps;         /* eigenproblem solver context */
  ST                 st;
  KSP                ksp;
  DS                 ds;
  PetscReal          cut,tol;
  PetscScalar        target;
  PetscInt           n=20,i,its,nev,ncv,mpd,Istart,Iend;
  PetscBool          flg,pur,track;
  EPSConvergedReason reason;
  EPSType            type;
  EPSExtraction      extr;
  EPSBalance         bal;
  EPSWhich           which;
  EPSConv            conv;
  EPSStop            stop;
  EPSProblemType     ptype;
  PetscErrorCode     ierr;
  PetscViewerAndFormat *vf;

  ierr = SlepcInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
  ierr = PetscPrintf(PETSC_COMM_WORLD,"\nDiagonal Eigenproblem, n=%D\n\n",n);CHKERRQ(ierr);

  ierr = MatCreate(PETSC_COMM_WORLD,&A);CHKERRQ(ierr);
  ierr = MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,n,n);CHKERRQ(ierr);
  ierr = MatSetFromOptions(A);CHKERRQ(ierr);
  ierr = MatSetUp(A);CHKERRQ(ierr);
  ierr = MatGetOwnershipRange(A,&Istart,&Iend);CHKERRQ(ierr);
  for (i=Istart;i<Iend;i++) {
    ierr = MatSetValue(A,i,i,i+1,INSERT_VALUES);CHKERRQ(ierr);
  }
  ierr = MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
  ierr = MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);

  /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
             Create eigensolver and test interface functions
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  ierr = EPSCreate(PETSC_COMM_WORLD,&eps);CHKERRQ(ierr);
  ierr = EPSSetOperators(eps,A,NULL);CHKERRQ(ierr);
  ierr = EPSGetOperators(eps,&B,NULL);CHKERRQ(ierr);
  ierr = MatView(B,NULL);CHKERRQ(ierr);

  ierr = EPSSetType(eps,EPSKRYLOVSCHUR);CHKERRQ(ierr);
  ierr = EPSGetType(eps,&type);CHKERRQ(ierr);
  ierr = PetscPrintf(PETSC_COMM_WORLD," Type set to %s\n",type);CHKERRQ(ierr);

  ierr = EPSGetProblemType(eps,&ptype);CHKERRQ(ierr);
  ierr = PetscPrintf(PETSC_COMM_WORLD," Problem type before changing = %d",(int)ptype);CHKERRQ(ierr);
  ierr = EPSSetProblemType(eps,EPS_HEP);CHKERRQ(ierr);
  ierr = EPSGetProblemType(eps,&ptype);CHKERRQ(ierr);
  ierr = PetscPrintf(PETSC_COMM_WORLD," ... changed to %d.",(int)ptype);CHKERRQ(ierr);
  ierr = EPSIsGeneralized(eps,&flg);CHKERRQ(ierr);
  if (flg) { ierr = PetscPrintf(PETSC_COMM_WORLD," generalized");CHKERRQ(ierr); }
  ierr = EPSIsHermitian(eps,&flg);CHKERRQ(ierr);
  if (flg) { ierr = PetscPrintf(PETSC_COMM_WORLD," hermitian");CHKERRQ(ierr); }
  ierr = EPSIsPositive(eps,&flg);CHKERRQ(ierr);
  if (flg) { ierr = PetscPrintf(PETSC_COMM_WORLD," positive");CHKERRQ(ierr); }

  ierr = EPSGetExtraction(eps,&extr);CHKERRQ(ierr);
  ierr = PetscPrintf(PETSC_COMM_WORLD,"\n Extraction before changing = %d",(int)extr);CHKERRQ(ierr);
  ierr = EPSSetExtraction(eps,EPS_HARMONIC);CHKERRQ(ierr);
  ierr = EPSGetExtraction(eps,&extr);CHKERRQ(ierr);
  ierr = PetscPrintf(PETSC_COMM_WORLD," ... changed to %d\n",(int)extr);CHKERRQ(ierr);

  ierr = EPSSetBalance(eps,EPS_BALANCE_ONESIDE,8,1e-6);CHKERRQ(ierr);
  ierr = EPSGetBalance(eps,&bal,&its,&cut);CHKERRQ(ierr);
  ierr = PetscPrintf(PETSC_COMM_WORLD," Balance: %s, its=%D, cutoff=%g\n",EPSBalanceTypes[bal],its,(double)cut);CHKERRQ(ierr);

  ierr = EPSSetPurify(eps,PETSC_FALSE);CHKERRQ(ierr);
  ierr = EPSGetPurify(eps,&pur);CHKERRQ(ierr);
  ierr = PetscPrintf(PETSC_COMM_WORLD," Eigenvector purification: %s\n",pur?"on":"off");CHKERRQ(ierr);
  ierr = EPSGetTrackAll(eps,&track);CHKERRQ(ierr);

  ierr = EPSSetTarget(eps,4.8);CHKERRQ(ierr);
  ierr = EPSGetTarget(eps,&target);CHKERRQ(ierr);
  ierr = EPSSetWhichEigenpairs(eps,EPS_TARGET_MAGNITUDE);CHKERRQ(ierr);
  ierr = EPSGetWhichEigenpairs(eps,&which);CHKERRQ(ierr);
  ierr = PetscPrintf(PETSC_COMM_WORLD," Which = %d, target = %g\n",(int)which,(double)PetscRealPart(target));CHKERRQ(ierr);

  ierr = EPSSetDimensions(eps,4,PETSC_DEFAULT,PETSC_DEFAULT);CHKERRQ(ierr);
  ierr = EPSGetDimensions(eps,&nev,&ncv,&mpd);CHKERRQ(ierr);
  ierr = PetscPrintf(PETSC_COMM_WORLD," Dimensions: nev=%D, ncv=%D, mpd=%D\n",nev,ncv,mpd);CHKERRQ(ierr);

  ierr = EPSSetTolerances(eps,2.2e-4,200);CHKERRQ(ierr);
  ierr = EPSGetTolerances(eps,&tol,&its);CHKERRQ(ierr);
  ierr = PetscPrintf(PETSC_COMM_WORLD," Tolerance = %.5f, max_its = %D\n",(double)tol,its);CHKERRQ(ierr);

  ierr = EPSSetConvergenceTest(eps,EPS_CONV_ABS);CHKERRQ(ierr);
  ierr = EPSGetConvergenceTest(eps,&conv);CHKERRQ(ierr);
  ierr = EPSSetStoppingTest(eps,EPS_STOP_BASIC);CHKERRQ(ierr);
  ierr = EPSGetStoppingTest(eps,&stop);CHKERRQ(ierr);
  ierr = PetscPrintf(PETSC_COMM_WORLD," Convergence test = %d, stopping test = %d\n",(int)conv,(int)stop);CHKERRQ(ierr);

  ierr = PetscViewerAndFormatCreate(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_DEFAULT,&vf);CHKERRQ(ierr);
  ierr = EPSMonitorSet(eps,(PetscErrorCode (*)(EPS,PetscInt,PetscInt,PetscScalar*,PetscScalar*,PetscReal*,PetscInt,void*))EPSMonitorFirst,vf,(PetscErrorCode (*)(void**))PetscViewerAndFormatDestroy);CHKERRQ(ierr);
  ierr = EPSMonitorCancel(eps);CHKERRQ(ierr);

  ierr = EPSGetST(eps,&st);CHKERRQ(ierr);
  ierr = STGetKSP(st,&ksp);CHKERRQ(ierr);
  ierr = KSPSetTolerances(ksp,1e-8,1e-35,PETSC_DEFAULT,PETSC_DEFAULT);CHKERRQ(ierr);
  ierr = STView(st,NULL);CHKERRQ(ierr);
  ierr = EPSGetDS(eps,&ds);CHKERRQ(ierr);
  ierr = DSView(ds,NULL);CHKERRQ(ierr);

  ierr = EPSSetFromOptions(eps);CHKERRQ(ierr);
  ierr = EPSSolve(eps);CHKERRQ(ierr);
  ierr = EPSGetConvergedReason(eps,&reason);CHKERRQ(ierr);
  ierr = EPSGetIterationNumber(eps,&its);CHKERRQ(ierr);
  ierr = PetscPrintf(PETSC_COMM_WORLD," Finished - converged reason = %d, its=%D\n",(int)reason,its);CHKERRQ(ierr);

  /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
                    Display solution and clean up
     - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
  ierr = EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);CHKERRQ(ierr);
  ierr = EPSDestroy(&eps);CHKERRQ(ierr);
  ierr = MatDestroy(&A);CHKERRQ(ierr);
  ierr = SlepcFinalize();
  return ierr;
}

/*TEST

   test:
      suffix: 1
      args: -eps_ncv 14
      filter: sed -e "s/00001/00000/"

TEST*/
