#include "rb_lapack.h"

extern VOID cheev_(char* jobz, char* uplo, integer* n, complex* a, integer* lda, real* w, complex* work, integer* lwork, real* rwork, integer* info);


static VALUE
rblapack_cheev(int argc, VALUE *argv, VALUE self){
  VALUE rblapack_jobz;
  char jobz; 
  VALUE rblapack_uplo;
  char uplo; 
  VALUE rblapack_a;
  complex *a; 
  VALUE rblapack_lwork;
  integer lwork; 
  VALUE rblapack_w;
  real *w; 
  VALUE rblapack_work;
  complex *work; 
  VALUE rblapack_info;
  integer info; 
  VALUE rblapack_a_out__;
  complex *a_out__;
  real *rwork;

  integer lda;
  integer n;

  VALUE rblapack_options;
  if (argc > 0 && TYPE(argv[argc-1]) == T_HASH) {
    argc--;
    rblapack_options = argv[argc];
    if (rb_hash_aref(rblapack_options, sHelp) == Qtrue) {
      printf("%s\n", "USAGE:\n  w, work, info, a = NumRu::Lapack.cheev( jobz, uplo, a, [:lwork => lwork, :usage => usage, :help => help])\n\n\nFORTRAN MANUAL\n      SUBROUTINE CHEEV( JOBZ, UPLO, N, A, LDA, W, WORK, LWORK, RWORK, INFO )\n\n*  Purpose\n*  =======\n*\n*  CHEEV computes all eigenvalues and, optionally, eigenvectors of a\n*  complex Hermitian matrix A.\n*\n\n*  Arguments\n*  =========\n*\n*  JOBZ    (input) CHARACTER*1\n*          = 'N':  Compute eigenvalues only;\n*          = 'V':  Compute eigenvalues and eigenvectors.\n*\n*  UPLO    (input) CHARACTER*1\n*          = 'U':  Upper triangle of A is stored;\n*          = 'L':  Lower triangle of A is stored.\n*\n*  N       (input) INTEGER\n*          The order of the matrix A.  N >= 0.\n*\n*  A       (input/output) COMPLEX array, dimension (LDA, N)\n*          On entry, the Hermitian matrix A.  If UPLO = 'U', the\n*          leading N-by-N upper triangular part of A contains the\n*          upper triangular part of the matrix A.  If UPLO = 'L',\n*          the leading N-by-N lower triangular part of A contains\n*          the lower triangular part of the matrix A.\n*          On exit, if JOBZ = 'V', then if INFO = 0, A contains the\n*          orthonormal eigenvectors of the matrix A.\n*          If JOBZ = 'N', then on exit the lower triangle (if UPLO='L')\n*          or the upper triangle (if UPLO='U') of A, including the\n*          diagonal, is destroyed.\n*\n*  LDA     (input) INTEGER\n*          The leading dimension of the array A.  LDA >= max(1,N).\n*\n*  W       (output) REAL array, dimension (N)\n*          If INFO = 0, the eigenvalues in ascending order.\n*\n*  WORK    (workspace/output) COMPLEX array, dimension (MAX(1,LWORK))\n*          On exit, if INFO = 0, WORK(1) returns the optimal LWORK.\n*\n*  LWORK   (input) INTEGER\n*          The length of the array WORK.  LWORK >= max(1,2*N-1).\n*          For optimal efficiency, LWORK >= (NB+1)*N,\n*          where NB is the blocksize for CHETRD returned by ILAENV.\n*\n*          If LWORK = -1, then a workspace query is assumed; the routine\n*          only calculates the optimal size of the WORK array, returns\n*          this value as the first entry of the WORK array, and no error\n*          message related to LWORK is issued by XERBLA.\n*\n*  RWORK   (workspace) REAL array, dimension (max(1, 3*N-2))\n*\n*  INFO    (output) INTEGER\n*          = 0:  successful exit\n*          < 0:  if INFO = -i, the i-th argument had an illegal value\n*          > 0:  if INFO = i, the algorithm failed to converge; i\n*                off-diagonal elements of an intermediate tridiagonal\n*                form did not converge to zero.\n*\n\n*  =====================================================================\n*\n\n");
      return Qnil;
    }
    if (rb_hash_aref(rblapack_options, sUsage) == Qtrue) {
      printf("%s\n", "USAGE:\n  w, work, info, a = NumRu::Lapack.cheev( jobz, uplo, a, [:lwork => lwork, :usage => usage, :help => help])\n");
      return Qnil;
    } 
  } else
    rblapack_options = Qnil;
  if (argc != 3 && argc != 4)
    rb_raise(rb_eArgError,"wrong number of arguments (%d for 3)", argc);
  rblapack_jobz = argv[0];
  rblapack_uplo = argv[1];
  rblapack_a = argv[2];
  if (argc == 4) {
    rblapack_lwork = argv[3];
  } else if (rblapack_options != Qnil) {
    rblapack_lwork = rb_hash_aref(rblapack_options, ID2SYM(rb_intern("lwork")));
  } else {
    rblapack_lwork = Qnil;
  }

  jobz = StringValueCStr(rblapack_jobz)[0];
  if (!NA_IsNArray(rblapack_a))
    rb_raise(rb_eArgError, "a (3th argument) must be NArray");
  if (NA_RANK(rblapack_a) != 2)
    rb_raise(rb_eArgError, "rank of a (3th argument) must be %d", 2);
  lda = NA_SHAPE0(rblapack_a);
  n = NA_SHAPE1(rblapack_a);
  if (NA_TYPE(rblapack_a) != NA_SCOMPLEX)
    rblapack_a = na_change_type(rblapack_a, NA_SCOMPLEX);
  a = NA_PTR_TYPE(rblapack_a, complex*);
  uplo = StringValueCStr(rblapack_uplo)[0];
  if (rblapack_lwork == Qnil)
    lwork = 2*n-1;
  else {
    lwork = NUM2INT(rblapack_lwork);
  }
  {
    na_shape_t shape[1];
    shape[0] = n;
    rblapack_w = na_make_object(NA_SFLOAT, 1, shape, cNArray);
  }
  w = NA_PTR_TYPE(rblapack_w, real*);
  {
    na_shape_t shape[1];
    shape[0] = MAX(1,lwork);
    rblapack_work = na_make_object(NA_SCOMPLEX, 1, shape, cNArray);
  }
  work = NA_PTR_TYPE(rblapack_work, complex*);
  {
    na_shape_t shape[2];
    shape[0] = lda;
    shape[1] = n;
    rblapack_a_out__ = na_make_object(NA_SCOMPLEX, 2, shape, cNArray);
  }
  a_out__ = NA_PTR_TYPE(rblapack_a_out__, complex*);
  MEMCPY(a_out__, a, complex, NA_TOTAL(rblapack_a));
  rblapack_a = rblapack_a_out__;
  a = a_out__;
  rwork = ALLOC_N(real, (MAX(1, 3*n-2)));

  cheev_(&jobz, &uplo, &n, a, &lda, w, work, &lwork, rwork, &info);

  free(rwork);
  rblapack_info = INT2NUM(info);
  return rb_ary_new3(4, rblapack_w, rblapack_work, rblapack_info, rblapack_a);
}

void
init_lapack_cheev(VALUE mLapack, VALUE sH, VALUE sU, VALUE zero){
  sHelp = sH;
  sUsage = sU;
  rblapack_ZERO = zero;

  rb_define_module_function(mLapack, "cheev", rblapack_cheev, -1);
}
