/*
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   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[] = "Solves a polynomial eigenproblem P(l)x = 0 with matrices loaded from a file.\n\n"
  "The command line options are:\n"
  "-A <filename1,filename2, ...> , where <filename1,.. > = matrices A0 ... files in PETSc binary form.\n\n";

#include <slepcpep.h>

#define MAX_MATRICES 40

int main(int argc,char **argv)
{
  Mat            A[MAX_MATRICES]; /* problem matrices */
  PEP            pep;             /* polynomial eigenproblem solver context */
  PetscReal      tol;
  PetscInt       nev,maxit,its,nmat=MAX_MATRICES,i;
  char*          filenames[MAX_MATRICES];
  PetscViewer    viewer;
  PetscBool      flg,terse;
  PetscErrorCode ierr;

  ierr = SlepcInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;

  /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
        Load the matrices that define the polynomial eigenproblem
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  ierr = PetscPrintf(PETSC_COMM_WORLD,"\nPolynomial eigenproblem stored in file.\n\n");CHKERRQ(ierr);
#if defined(PETSC_USE_COMPLEX)
  ierr = PetscPrintf(PETSC_COMM_WORLD," Reading COMPLEX matrices from binary files...\n");CHKERRQ(ierr);
#else
  ierr = PetscPrintf(PETSC_COMM_WORLD," Reading REAL matrices from binary files...\n");CHKERRQ(ierr);
#endif
  ierr = PetscOptionsGetStringArray(NULL,NULL,"-A",filenames,&nmat,&flg);CHKERRQ(ierr);
  if (!flg) SETERRQ(PETSC_COMM_WORLD,1,"Must indicate a comma-separated list of file names with the -A option");
  for (i=0;i<nmat;i++) {
    ierr = PetscViewerBinaryOpen(PETSC_COMM_WORLD,filenames[i],FILE_MODE_READ,&viewer);CHKERRQ(ierr);
    ierr = MatCreate(PETSC_COMM_WORLD,&A[i]);CHKERRQ(ierr);
    ierr = MatSetFromOptions(A[i]);CHKERRQ(ierr);
    ierr = MatLoad(A[i],viewer);CHKERRQ(ierr);
    ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
  }
  /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
                Create the eigensolver and set various options
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  /*
     Create eigensolver context
  */
  ierr = PEPCreate(PETSC_COMM_WORLD,&pep);CHKERRQ(ierr);

  /*
     Set matrices
  */
  ierr = PEPSetOperators(pep,nmat,A);CHKERRQ(ierr);
  /*
     Set solver parameters at runtime
  */
  ierr = PEPSetFromOptions(pep);CHKERRQ(ierr);

  /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
                      Solve the eigensystem
     - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

  ierr = PEPSolve(pep);CHKERRQ(ierr);
  ierr = PEPGetIterationNumber(pep,&its);CHKERRQ(ierr);
  ierr = PetscPrintf(PETSC_COMM_WORLD," Number of iterations of the method: %D\n",its);CHKERRQ(ierr);

  /*
     Optional: Get some information from the solver and display it
  */
  ierr = PEPGetDimensions(pep,&nev,NULL,NULL);CHKERRQ(ierr);
  ierr = PetscPrintf(PETSC_COMM_WORLD," Number of requested eigenvalues: %D\n",nev);CHKERRQ(ierr);
  ierr = PEPGetTolerances(pep,&tol,&maxit);CHKERRQ(ierr);
  ierr = PetscPrintf(PETSC_COMM_WORLD," Stopping condition: tol=%.4g, maxit=%D\n",(double)tol,maxit);CHKERRQ(ierr);

  /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
                    Display solution and clean up
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  /* show detailed info unless -terse option is given by user */
  ierr = PetscOptionsHasName(NULL,NULL,"-terse",&terse);CHKERRQ(ierr);
  if (terse) {
    ierr = PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL);CHKERRQ(ierr);
  } else {
    ierr = PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);CHKERRQ(ierr);
    ierr = PEPConvergedReasonView(pep,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
    ierr = PEPErrorView(pep,PEP_ERROR_BACKWARD,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
    ierr = PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
  }
  ierr = PEPDestroy(&pep);CHKERRQ(ierr);
  for (i=0;i<nmat;i++) {
    ierr = MatDestroy(&A[i]);CHKERRQ(ierr);
    ierr = PetscFree(filenames[i]);CHKERRQ(ierr);
  }
  ierr = SlepcFinalize();
  return ierr;
}

/*TEST

   test:
      suffix: 1
      args: -A ${SLEPC_DIR}/share/slepc/datafiles/matrices/speaker107k.petsc,${SLEPC_DIR}/share/slepc/datafiles/matrices/speaker107c.petsc,${SLEPC_DIR}/share/slepc/datafiles/matrices/speaker107m.petsc -pep_type {{toar qarnoldi linear}} -pep_nev 4 -pep_ncv 20 -pep_scale scalar -terse
      requires: double !complex !define(PETSC_USE_64BIT_INDICES)

TEST*/
