#include <petsc.h>
static char help[] = "";

int main(int argc,char **args)
{
  PetscInt  n = 2;
  Mat       array[1],B,conjugate;
  PetscBool flg = PETSC_FALSE, correct = PETSC_FALSE;

  PetscCall(PetscInitialize(&argc,&args,NULL,help));
  PetscCall(MatCreateConstantDiagonal(PETSC_COMM_WORLD,n,n,n,n,-1.0,array));
  PetscCall(MatConvert(array[0],MATDENSE,MAT_INPLACE_MATRIX,array));
  PetscCall(MatSetRandom(array[0],NULL));
  PetscCall(MatViewFromOptions(array[0],NULL,"-A_view"));
  PetscCall(PetscOptionsGetBool(NULL,NULL,"-convert",&flg,NULL));
  if (flg) {
    PetscCall(MatConvert(array[0],MATAIJ,MAT_INPLACE_MATRIX,array));
    PetscCall(PetscOptionsGetBool(NULL,NULL,"-correct",&correct,NULL));
  }
  PetscCall(MatProductCreate(array[0],array[0],NULL,&B));
  PetscCall(MatProductSetType(B,MATPRODUCT_AtB));
  PetscCall(MatProductSetFromOptions(B));
  PetscCall(MatProductSymbolic(B));
  if (PetscDefined(USE_COMPLEX)) {
    PetscCall(MatDuplicate(array[0], MAT_COPY_VALUES, &conjugate));
    PetscCall(MatConjugate(conjugate));
    if (!correct) PetscCall(MatProductReplaceMats(conjugate,array[0],NULL,B));
    else PetscCall(MatProductReplaceMats(array[0],conjugate,NULL,B));
  }
  PetscCall(MatProductNumeric(B));
  if (PetscDefined(USE_COMPLEX)) {
    PetscCall(MatDestroy(&conjugate));
    if (correct) PetscCall(MatConjugate(B));
  }
  PetscCall(MatViewFromOptions(B,NULL,"-product_view"));
  PetscCall(MatDestroy(&B));
  PetscCall(MatDestroy(array));
  PetscCall(PetscFinalize());
  return 0;
}