/*
   - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   SLEPc - Scalable Library for Eigenvalue Problem Computations
   Copyright (c) 2002-2021, 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 DSGHIEP with compact storage.\n\n";

#include <slepcds.h>

int main(int argc,char **argv)
{
  PetscErrorCode ierr;
  DS             ds;
  SlepcSC        sc;
  PetscReal      *T,*s,re,im;
  PetscScalar    *eigr,*eigi;
  PetscInt       i,n=10,l=2,k=5,ld;
  PetscViewer    viewer;
  PetscBool      verbose;

  ierr = SlepcInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
  ierr = PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);CHKERRQ(ierr);
  ierr = PetscPrintf(PETSC_COMM_WORLD,"Solve a Dense System of type GHIEP with compact storage - dimension %D.\n",n);CHKERRQ(ierr);
  ierr = PetscOptionsGetInt(NULL,NULL,"-l",&l,NULL);CHKERRQ(ierr);
  ierr = PetscOptionsGetInt(NULL,NULL,"-k",&k,NULL);CHKERRQ(ierr);
  if (l>n || k>n || l>k) SETERRQ(PETSC_COMM_WORLD,1,"Wrong value of dimensions");
  ierr = PetscOptionsHasName(NULL,NULL,"-verbose",&verbose);CHKERRQ(ierr);

  /* Create DS object */
  ierr = DSCreate(PETSC_COMM_WORLD,&ds);CHKERRQ(ierr);
  ierr = DSSetType(ds,DSGHIEP);CHKERRQ(ierr);
  ierr = DSSetFromOptions(ds);CHKERRQ(ierr);
  ld = n+2;  /* test leading dimension larger than n */
  ierr = DSAllocate(ds,ld);CHKERRQ(ierr);
  ierr = DSSetDimensions(ds,n,0,l,k);CHKERRQ(ierr);
  ierr = DSSetCompact(ds,PETSC_TRUE);CHKERRQ(ierr);

  /* Set up viewer */
  ierr = PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&viewer);CHKERRQ(ierr);
  ierr = PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO_DETAIL);CHKERRQ(ierr);
  ierr = DSView(ds,viewer);CHKERRQ(ierr);
  ierr = PetscViewerPopFormat(viewer);CHKERRQ(ierr);
  ierr = PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB);CHKERRQ(ierr);

  /* Fill arrow-tridiagonal matrix */
  ierr = DSGetArrayReal(ds,DS_MAT_T,&T);CHKERRQ(ierr);
  ierr = DSGetArrayReal(ds,DS_MAT_D,&s);CHKERRQ(ierr);
  for (i=0;i<n;i++) T[i] = (PetscReal)(i+1);
  for (i=k;i<n-1;i++) T[i+ld] = 1.0;
  for (i=l;i<k;i++) T[i+2*ld] = 1.0;
  T[2*ld+l+1] = -7; T[ld+k+1] = -7;
  /* Signature matrix */
  for (i=0;i<n;i++) s[i] = 1.0;
  s[l+1] = -1.0;
  s[k+1] = -1.0;
  ierr = DSRestoreArrayReal(ds,DS_MAT_T,&T);CHKERRQ(ierr);
  ierr = DSRestoreArrayReal(ds,DS_MAT_D,&s);CHKERRQ(ierr);
  if (l==0 && k==0) {
    ierr = DSSetState(ds,DS_STATE_INTERMEDIATE);CHKERRQ(ierr);
  } else {
    ierr = DSSetState(ds,DS_STATE_RAW);CHKERRQ(ierr);
  }
  ierr = PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n");CHKERRQ(ierr);
  ierr = DSView(ds,viewer);CHKERRQ(ierr);

  /* Solve */
  ierr = PetscCalloc2(n,&eigr,n,&eigi);CHKERRQ(ierr);
  ierr = DSGetSlepcSC(ds,&sc);CHKERRQ(ierr);
  sc->comparison    = SlepcCompareLargestMagnitude;
  sc->comparisonctx = NULL;
  sc->map           = NULL;
  sc->mapobj        = NULL;
  ierr = DSSolve(ds,eigr,eigi);CHKERRQ(ierr);
  ierr = DSSort(ds,eigr,eigi,NULL,NULL,NULL);CHKERRQ(ierr);
  if (verbose) {
    ierr = PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n");CHKERRQ(ierr);
    ierr = DSView(ds,viewer);CHKERRQ(ierr);
  }

  /* Print eigenvalues */
  ierr = PetscPrintf(PETSC_COMM_WORLD,"Computed eigenvalues =\n");CHKERRQ(ierr);
  for (i=0;i<n;i++) {
#if defined(PETSC_USE_COMPLEX)
    re = PetscRealPart(eigr[i]);
    im = PetscImaginaryPart(eigr[i]);
#else
    re = eigr[i];
    im = eigi[i];
#endif
    if (PetscAbs(im)<1e-10) {
      ierr = PetscViewerASCIIPrintf(viewer,"  %.5f\n",(double)re);CHKERRQ(ierr);
    } else {
      ierr = PetscViewerASCIIPrintf(viewer,"  %.5f%+.5fi\n",(double)re,(double)im);CHKERRQ(ierr);
    }
  }
  ierr = PetscFree2(eigr,eigi);CHKERRQ(ierr);
  ierr = DSDestroy(&ds);CHKERRQ(ierr);
  ierr = SlepcFinalize();
  return ierr;
}

/*TEST

   test:
      suffix: 1
      requires: !single
      args: -ds_method {{0 1 2}}
      filter: grep -v "solving the problem"

   test:
      suffix: 2
      args: -n 5 -k 4 -l 4 -ds_method {{0 1 2}}
      filter: grep -v "solving the problem"

TEST*/
