#include "rb_lapack.h"

extern VOID cpbtrs_(char* uplo, integer* n, integer* kd, integer* nrhs, complex* ab, integer* ldab, complex* b, integer* ldb, integer* info);


static VALUE
rblapack_cpbtrs(int argc, VALUE *argv, VALUE self){
  VALUE rblapack_uplo;
  char uplo; 
  VALUE rblapack_kd;
  integer kd; 
  VALUE rblapack_ab;
  complex *ab; 
  VALUE rblapack_b;
  complex *b; 
  VALUE rblapack_info;
  integer info; 
  VALUE rblapack_b_out__;
  complex *b_out__;

  integer ldab;
  integer n;
  integer ldb;
  integer nrhs;

  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  info, b = NumRu::Lapack.cpbtrs( uplo, kd, ab, b, [:usage => usage, :help => help])\n\n\nFORTRAN MANUAL\n      SUBROUTINE CPBTRS( UPLO, N, KD, NRHS, AB, LDAB, B, LDB, INFO )\n\n*  Purpose\n*  =======\n*\n*  CPBTRS solves a system of linear equations A*X = B with a Hermitian\n*  positive definite band matrix A using the Cholesky factorization\n*  A = U**H*U or A = L*L**H computed by CPBTRF.\n*\n\n*  Arguments\n*  =========\n*\n*  UPLO    (input) CHARACTER*1\n*          = 'U':  Upper triangular factor stored in AB;\n*          = 'L':  Lower triangular factor stored in AB.\n*\n*  N       (input) INTEGER\n*          The order of the matrix A.  N >= 0.\n*\n*  KD      (input) INTEGER\n*          The number of superdiagonals of the matrix A if UPLO = 'U',\n*          or the number of subdiagonals if UPLO = 'L'.  KD >= 0.\n*\n*  NRHS    (input) INTEGER\n*          The number of right hand sides, i.e., the number of columns\n*          of the matrix B.  NRHS >= 0.\n*\n*  AB      (input) COMPLEX array, dimension (LDAB,N)\n*          The triangular factor U or L from the Cholesky factorization\n*          A = U**H*U or A = L*L**H of the band matrix A, stored in the\n*          first KD+1 rows of the array.  The j-th column of U or L is\n*          stored in the j-th column of the array AB as follows:\n*          if UPLO ='U', AB(kd+1+i-j,j) = U(i,j) for max(1,j-kd)<=i<=j;\n*          if UPLO ='L', AB(1+i-j,j)    = L(i,j) for j<=i<=min(n,j+kd).\n*\n*  LDAB    (input) INTEGER\n*          The leading dimension of the array AB.  LDAB >= KD+1.\n*\n*  B       (input/output) COMPLEX array, dimension (LDB,NRHS)\n*          On entry, the right hand side matrix B.\n*          On exit, the solution matrix X.\n*\n*  LDB     (input) INTEGER\n*          The leading dimension of the array B.  LDB >= max(1,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*  =====================================================================\n*\n*     .. Local Scalars ..\n      LOGICAL            UPPER\n      INTEGER            J\n*     ..\n*     .. External Functions ..\n      LOGICAL            LSAME\n      EXTERNAL           LSAME\n*     ..\n*     .. External Subroutines ..\n      EXTERNAL           CTBSV, XERBLA\n*     ..\n*     .. Intrinsic Functions ..\n      INTRINSIC          MAX\n*     ..\n\n");
      return Qnil;
    }
    if (rb_hash_aref(rblapack_options, sUsage) == Qtrue) {
      printf("%s\n", "USAGE:\n  info, b = NumRu::Lapack.cpbtrs( uplo, kd, ab, b, [:usage => usage, :help => help])\n");
      return Qnil;
    } 
  } else
    rblapack_options = Qnil;
  if (argc != 4 && argc != 4)
    rb_raise(rb_eArgError,"wrong number of arguments (%d for 4)", argc);
  rblapack_uplo = argv[0];
  rblapack_kd = argv[1];
  rblapack_ab = argv[2];
  rblapack_b = argv[3];
  if (argc == 4) {
  } else if (rblapack_options != Qnil) {
  } else {
  }

  uplo = StringValueCStr(rblapack_uplo)[0];
  if (!NA_IsNArray(rblapack_ab))
    rb_raise(rb_eArgError, "ab (3th argument) must be NArray");
  if (NA_RANK(rblapack_ab) != 2)
    rb_raise(rb_eArgError, "rank of ab (3th argument) must be %d", 2);
  ldab = NA_SHAPE0(rblapack_ab);
  n = NA_SHAPE1(rblapack_ab);
  if (NA_TYPE(rblapack_ab) != NA_SCOMPLEX)
    rblapack_ab = na_change_type(rblapack_ab, NA_SCOMPLEX);
  ab = NA_PTR_TYPE(rblapack_ab, complex*);
  kd = NUM2INT(rblapack_kd);
  if (!NA_IsNArray(rblapack_b))
    rb_raise(rb_eArgError, "b (4th argument) must be NArray");
  if (NA_RANK(rblapack_b) != 2)
    rb_raise(rb_eArgError, "rank of b (4th argument) must be %d", 2);
  ldb = NA_SHAPE0(rblapack_b);
  nrhs = NA_SHAPE1(rblapack_b);
  if (NA_TYPE(rblapack_b) != NA_SCOMPLEX)
    rblapack_b = na_change_type(rblapack_b, NA_SCOMPLEX);
  b = NA_PTR_TYPE(rblapack_b, complex*);
  {
    na_shape_t shape[2];
    shape[0] = ldb;
    shape[1] = nrhs;
    rblapack_b_out__ = na_make_object(NA_SCOMPLEX, 2, shape, cNArray);
  }
  b_out__ = NA_PTR_TYPE(rblapack_b_out__, complex*);
  MEMCPY(b_out__, b, complex, NA_TOTAL(rblapack_b));
  rblapack_b = rblapack_b_out__;
  b = b_out__;

  cpbtrs_(&uplo, &n, &kd, &nrhs, ab, &ldab, b, &ldb, &info);

  rblapack_info = INT2NUM(info);
  return rb_ary_new3(2, rblapack_info, rblapack_b);
}

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

  rb_define_module_function(mLapack, "cpbtrs", rblapack_cpbtrs, -1);
}
