#include "rb_lapack.h"

extern VOID zgeqp3_(integer* m, integer* n, doublecomplex* a, integer* lda, integer* jpvt, doublecomplex* tau, doublecomplex* work, integer* lwork, doublereal* rwork, integer* info);


static VALUE
rblapack_zgeqp3(int argc, VALUE *argv, VALUE self){
  VALUE rblapack_m;
  integer m; 
  VALUE rblapack_a;
  doublecomplex *a; 
  VALUE rblapack_jpvt;
  integer *jpvt; 
  VALUE rblapack_lwork;
  integer lwork; 
  VALUE rblapack_tau;
  doublecomplex *tau; 
  VALUE rblapack_work;
  doublecomplex *work; 
  VALUE rblapack_info;
  integer info; 
  VALUE rblapack_a_out__;
  doublecomplex *a_out__;
  VALUE rblapack_jpvt_out__;
  integer *jpvt_out__;
  doublereal *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  tau, work, info, a, jpvt = NumRu::Lapack.zgeqp3( m, a, jpvt, [:lwork => lwork, :usage => usage, :help => help])\n\n\nFORTRAN MANUAL\n      SUBROUTINE ZGEQP3( M, N, A, LDA, JPVT, TAU, WORK, LWORK, RWORK, INFO )\n\n*  Purpose\n*  =======\n*\n*  ZGEQP3 computes a QR factorization with column pivoting of a\n*  matrix A:  A*P = Q*R  using Level 3 BLAS.\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*16 array, dimension (LDA,N)\n*          On entry, the M-by-N matrix A.\n*          On exit, the upper triangle of the array contains the\n*          min(M,N)-by-N upper trapezoidal matrix R; the elements below\n*          the diagonal, together with the array TAU, represent the\n*          unitary matrix Q as a product of min(M,N) elementary\n*          reflectors.\n*\n*  LDA     (input) INTEGER\n*          The leading dimension of the array A. LDA >= max(1,M).\n*\n*  JPVT    (input/output) INTEGER array, dimension (N)\n*          On entry, if JPVT(J).ne.0, the J-th column of A is permuted\n*          to the front of A*P (a leading column); if JPVT(J)=0,\n*          the J-th column of A is a free column.\n*          On exit, if JPVT(J)=K, then the J-th column of A*P was the\n*          the K-th column of A.\n*\n*  TAU     (output) COMPLEX*16 array, dimension (min(M,N))\n*          The scalar factors of the elementary reflectors.\n*\n*  WORK    (workspace/output) COMPLEX*16 array, dimension (MAX(1,LWORK))\n*          On exit, if INFO=0, WORK(1) returns the optimal LWORK.\n*\n*  LWORK   (input) INTEGER\n*          The dimension of the array WORK. LWORK >= N+1.\n*          For optimal performance LWORK >= ( N+1 )*NB, where NB\n*          is the optimal blocksize.\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) DOUBLE PRECISION array, dimension (2*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(1) H(2) . . . H(k), 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 real/complex scalar, and v is a real/complex vector\n*  with v(1:i-1) = 0 and v(i) = 1; v(i+1:m) is stored on exit in\n*  A(i+1:m,i), and tau in TAU(i).\n*\n*  Based on contributions by\n*    G. Quintana-Orti, Depto. de Informatica, Universidad Jaime I, Spain\n*    X. Sun, Computer Science Dept., Duke University, USA\n*\n*  =====================================================================\n*\n\n");
      return Qnil;
    }
    if (rb_hash_aref(rblapack_options, sUsage) == Qtrue) {
      printf("%s\n", "USAGE:\n  tau, work, info, a, jpvt = NumRu::Lapack.zgeqp3( m, a, jpvt, [: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_m = argv[0];
  rblapack_a = argv[1];
  rblapack_jpvt = 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;
  }

  m = NUM2INT(rblapack_m);
  if (!NA_IsNArray(rblapack_jpvt))
    rb_raise(rb_eArgError, "jpvt (3th argument) must be NArray");
  if (NA_RANK(rblapack_jpvt) != 1)
    rb_raise(rb_eArgError, "rank of jpvt (3th argument) must be %d", 1);
  n = NA_SHAPE0(rblapack_jpvt);
  if (NA_TYPE(rblapack_jpvt) != NA_LINT)
    rblapack_jpvt = na_change_type(rblapack_jpvt, NA_LINT);
  jpvt = NA_PTR_TYPE(rblapack_jpvt, integer*);
  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);
  if (NA_SHAPE1(rblapack_a) != n)
    rb_raise(rb_eRuntimeError, "shape 1 of a must be the same as shape 0 of jpvt");
  if (NA_TYPE(rblapack_a) != NA_DCOMPLEX)
    rblapack_a = na_change_type(rblapack_a, NA_DCOMPLEX);
  a = NA_PTR_TYPE(rblapack_a, doublecomplex*);
  if (rblapack_lwork == Qnil)
    lwork = n+1;
  else {
    lwork = NUM2INT(rblapack_lwork);
  }
  {
    na_shape_t shape[1];
    shape[0] = MIN(m,n);
    rblapack_tau = na_make_object(NA_DCOMPLEX, 1, shape, cNArray);
  }
  tau = NA_PTR_TYPE(rblapack_tau, doublecomplex*);
  {
    na_shape_t shape[1];
    shape[0] = MAX(1,lwork);
    rblapack_work = na_make_object(NA_DCOMPLEX, 1, shape, cNArray);
  }
  work = NA_PTR_TYPE(rblapack_work, doublecomplex*);
  {
    na_shape_t shape[2];
    shape[0] = lda;
    shape[1] = n;
    rblapack_a_out__ = na_make_object(NA_DCOMPLEX, 2, shape, cNArray);
  }
  a_out__ = NA_PTR_TYPE(rblapack_a_out__, doublecomplex*);
  MEMCPY(a_out__, a, doublecomplex, NA_TOTAL(rblapack_a));
  rblapack_a = rblapack_a_out__;
  a = a_out__;
  {
    na_shape_t shape[1];
    shape[0] = n;
    rblapack_jpvt_out__ = na_make_object(NA_LINT, 1, shape, cNArray);
  }
  jpvt_out__ = NA_PTR_TYPE(rblapack_jpvt_out__, integer*);
  MEMCPY(jpvt_out__, jpvt, integer, NA_TOTAL(rblapack_jpvt));
  rblapack_jpvt = rblapack_jpvt_out__;
  jpvt = jpvt_out__;
  rwork = ALLOC_N(doublereal, (2*n));

  zgeqp3_(&m, &n, a, &lda, jpvt, tau, work, &lwork, rwork, &info);

  free(rwork);
  rblapack_info = INT2NUM(info);
  return rb_ary_new3(5, rblapack_tau, rblapack_work, rblapack_info, rblapack_a, rblapack_jpvt);
}

void
init_lapack_zgeqp3(VALUE mLapack, VALUE sH, VALUE sU, VALUE zero){
  sHelp = sH;
  sUsage = sU;
  rblapack_ZERO = zero;

  rb_define_module_function(mLapack, "zgeqp3", rblapack_zgeqp3, -1);
}
