#include "rb_lapack.h"

extern VOID cgeql2_(integer* m, integer* n, complex* a, integer* lda, complex* tau, complex* work, integer* info);


static VALUE
rblapack_cgeql2(int argc, VALUE *argv, VALUE self){
  VALUE rblapack_m;
  integer m; 
  VALUE rblapack_a;
  complex *a; 
  VALUE rblapack_tau;
  complex *tau; 
  VALUE rblapack_info;
  integer info; 
  VALUE rblapack_a_out__;
  complex *a_out__;
  complex *work;

  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  tau, info, a = NumRu::Lapack.cgeql2( m, a, [:usage => usage, :help => help])\n\n\nFORTRAN MANUAL\n      SUBROUTINE CGEQL2( M, N, A, LDA, TAU, WORK, INFO )\n\n*  Purpose\n*  =======\n*\n*  CGEQL2 computes a QL factorization of a complex m by n matrix A:\n*  A = Q * L.\n*\n\n*  Arguments\n*  =========\n*\n*  M       (input) INTEGER\n*          The number of rows of the matrix A.  M >= 0.\n*\n*  N       (input) INTEGER\n*          The number of columns of the matrix A.  N >= 0.\n*\n*  A       (input/output) COMPLEX array, dimension (LDA,N)\n*          On entry, the m by n matrix A.\n*          On exit, if m >= n, the lower triangle of the subarray\n*          A(m-n+1:m,1:n) contains the n by n lower triangular matrix L;\n*          if m <= n, the elements on and below the (n-m)-th\n*          superdiagonal contain the m by n lower trapezoidal matrix L;\n*          the remaining elements, with the array TAU, represent the\n*          unitary matrix Q as a product of elementary reflectors\n*          (see Further Details).\n*\n*  LDA     (input) INTEGER\n*          The leading dimension of the array A.  LDA >= max(1,M).\n*\n*  TAU     (output) COMPLEX array, dimension (min(M,N))\n*          The scalar factors of the elementary reflectors (see Further\n*          Details).\n*\n*  WORK    (workspace) COMPLEX array, dimension (N)\n*\n*  INFO    (output) INTEGER\n*          = 0: successful exit\n*          < 0: if INFO = -i, the i-th argument had an illegal value\n*\n\n*  Further Details\n*  ===============\n*\n*  The matrix Q is represented as a product of elementary reflectors\n*\n*     Q = H(k) . . . H(2) H(1), where k = min(m,n).\n*\n*  Each H(i) has the form\n*\n*     H(i) = I - tau * v * v'\n*\n*  where tau is a complex scalar, and v is a complex vector with\n*  v(m-k+i+1:m) = 0 and v(m-k+i) = 1; v(1:m-k+i-1) is stored on exit in\n*  A(1:m-k+i-1,n-k+i), and tau in TAU(i).\n*\n*  =====================================================================\n*\n\n");
      return Qnil;
    }
    if (rb_hash_aref(rblapack_options, sUsage) == Qtrue) {
      printf("%s\n", "USAGE:\n  tau, info, a = NumRu::Lapack.cgeql2( m, a, [:usage => usage, :help => help])\n");
      return Qnil;
    } 
  } else
    rblapack_options = Qnil;
  if (argc != 2 && argc != 2)
    rb_raise(rb_eArgError,"wrong number of arguments (%d for 2)", argc);
  rblapack_m = argv[0];
  rblapack_a = argv[1];
  if (argc == 2) {
  } else if (rblapack_options != Qnil) {
  } else {
  }

  m = NUM2INT(rblapack_m);
  if (!NA_IsNArray(rblapack_a))
    rb_raise(rb_eArgError, "a (2th argument) must be NArray");
  if (NA_RANK(rblapack_a) != 2)
    rb_raise(rb_eArgError, "rank of a (2th 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*);
  {
    na_shape_t shape[1];
    shape[0] = MIN(m,n);
    rblapack_tau = na_make_object(NA_SCOMPLEX, 1, shape, cNArray);
  }
  tau = NA_PTR_TYPE(rblapack_tau, 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__;
  work = ALLOC_N(complex, (n));

  cgeql2_(&m, &n, a, &lda, tau, work, &info);

  free(work);
  rblapack_info = INT2NUM(info);
  return rb_ary_new3(3, rblapack_tau, rblapack_info, rblapack_a);
}

void
init_lapack_cgeql2(VALUE mLapack, VALUE sH, VALUE sU, VALUE zero){
  sHelp = sH;
  sUsage = sU;
  rblapack_ZERO = zero;

  rb_define_module_function(mLapack, "cgeql2", rblapack_cgeql2, -1);
}
