new file mode 100644
--- /dev/null
+++ b/liboctave/DAE.cc
@@ -0,0 +1,70 @@
+// DAE.cc                                               -*- C++ -*-
+/*
+
+Copyright (C) 1996 John W. Eaton
+
+This file is part of Octave.
+
+Octave is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by the
+Free Software Foundation; either version 2, or (at your option) any
+later version.
+
+Octave is distributed in the hope that it will be useful, but WITHOUT
+ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with Octave; see the file COPYING.  If not, write to the Free
+Software Foundation, 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+
+*/
+
+#if defined (__GNUG__)
+#pragma implementation
+#endif
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include "DAE.h"
+#include "lo-error.h"
+
+DAE::DAE (const ColumnVector& x, const ColumnVector& xxdot,
+	  double t, DAEFunc& f)
+  : base_diff_eqn (x, t), DAEFunc (f), xdot (xxdot)
+{
+  if (x.length () != xdot.length ())
+    ; // XXX FIXME XXX -- exception!
+}
+
+void
+DAE::initialize (const ColumnVector& xx, double t)
+{
+  if (xx.length () != xdot.length ())
+    ; // XXX FIXME XXX -- exception!
+  else
+    base_diff_eqn::initialize (xx, t);
+}
+
+void
+DAE::initialize (const ColumnVector& xx, const ColumnVector& xxdot,
+		 double t)
+{
+  if (xx.length () != xxdot.length ())
+    ; // XXX FIXME XXX -- exception!
+  else
+    {
+      base_diff_eqn::initialize (xx, t);
+      xdot = xxdot;
+    }
+}
+
+/*
+;;; Local Variables: ***
+;;; mode: C++ ***
+;;; page-delimiter: "^/\\*" ***
+;;; End: ***
+*/

new file mode 100644
--- /dev/null
+++ b/liboctave/DASSL.h
@@ -0,0 +1,127 @@
+// DASSL.h                                                -*- C++ -*-
+/*
+
+Copyright (C) 1996 John W. Eaton
+
+This file is part of Octave.
+
+Octave is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by the
+Free Software Foundation; either version 2, or (at your option) any
+later version.
+
+Octave is distributed in the hope that it will be useful, but WITHOUT
+ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with Octave; see the file COPYING.  If not, write to the Free
+Software Foundation, 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+
+*/
+
+#if !defined (octave_DASSL_h)
+#define octave_DASSL_h 1
+
+#if defined (__GNUG__)
+#pragma interface
+#endif
+
+#include "DAE.h"
+
+class DASSL_options
+{
+ public:
+
+  DASSL_options (void);
+  DASSL_options (const DASSL_options& opt);
+
+  DASSL_options& operator = (const DASSL_options& opt);
+
+  ~DASSL_options (void);
+
+  void init (void);
+  void copy (const DASSL_options& opt);
+
+  void set_default_options (void);
+
+  void set_absolute_tolerance (double);
+  void set_initial_step_size (double);
+  void set_maximum_step_size (double);
+  void set_minimum_step_size (double);
+  void set_relative_tolerance (double);
+
+  double absolute_tolerance (void);
+  double initial_step_size (void);
+  double maximum_step_size (void);
+  double minimum_step_size (void);
+  double relative_tolerance (void);
+
+ private:
+
+  double x_absolute_tolerance;
+  double x_initial_step_size;
+  double x_maximum_step_size;
+  double x_minimum_step_size;
+  double x_relative_tolerance;
+};
+
+class DASSL : public DAE, public DASSL_options
+{
+public:
+
+  DASSL (void);
+
+  DASSL (const ColumnVector& x, double time, DAEFunc& f);
+
+  DASSL (const ColumnVector& x, const ColumnVector& xdot,
+	 double time, DAEFunc& f);
+
+ ~DASSL (void);
+
+  void force_restart (void);
+
+  void set_stop_time (double t);
+  void clear_stop_time (void);
+
+  ColumnVector do_integrate (double t);
+
+  Matrix do_integrate (const ColumnVector& tout);
+
+  Matrix integrate (const ColumnVector& tout, Matrix& xdot_out);
+
+  Matrix integrate (const ColumnVector& tout, Matrix& xdot_out,
+		    const ColumnVector& tcrit); 
+
+private:
+
+  double stop_time;
+  int stop_time_set;
+
+  int n;
+  int integration_error;
+  int restart;
+  int liw;  
+  int lrw;
+  int idid;
+  int *info;
+  int *iwork;
+  double *rwork;
+
+  friend int ddassl_j (double *time, double *state, double *deriv,
+		       double *pd, double *cj, double *rpar, int *ipar);
+
+  friend int ddassl_f (double *time, double *state, double *deriv,
+		       double *delta, int *ires, double *rpar, int *ipar);
+
+};
+
+#endif
+
+/*
+;;; Local Variables: ***
+;;; mode: C++ ***
+;;; page-delimiter: "^/\\*" ***
+;;; End: ***
+*/

new file mode 100644
--- /dev/null
+++ b/liboctave/LSODE.h
@@ -0,0 +1,135 @@
+// LSODE.h                                                -*- C++ -*-
+/*
+
+Copyright (C) 1996 John W. Eaton
+
+This file is part of Octave.
+
+Octave is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by the
+Free Software Foundation; either version 2, or (at your option) any
+later version.
+
+Octave is distributed in the hope that it will be useful, but WITHOUT
+ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with Octave; see the file COPYING.  If not, write to the Free
+Software Foundation, 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+
+*/
+
+#if !defined (octave_LSODE_h)
+#define octave_LSODE_h 1
+
+#if defined (__GNUG__)
+#pragma interface
+#endif
+
+#if 0
+class ostream;
+#endif
+
+#include "ODE.h"
+
+class LSODE_options
+{
+ public:
+
+  LSODE_options (void);
+  LSODE_options (const LSODE_options& opt);
+
+  LSODE_options& operator = (const LSODE_options& opt);
+
+  ~LSODE_options (void);
+
+  void init (void);
+  void copy (const LSODE_options& opt);
+
+  void set_default_options (void);
+
+  void set_absolute_tolerance (double);
+  void set_initial_step_size (double);
+  void set_maximum_step_size (double);
+  void set_minimum_step_size (double);
+  void set_relative_tolerance (double);
+
+  double absolute_tolerance (void);
+  double initial_step_size (void);
+  double maximum_step_size (void);
+  double minimum_step_size (void);
+  double relative_tolerance (void);
+
+ private:
+
+  double x_absolute_tolerance;
+  double x_initial_step_size;
+  double x_maximum_step_size;
+  double x_minimum_step_size;
+  double x_relative_tolerance;
+};
+
+class LSODE : public ODE, public LSODE_options
+{
+public:
+
+  LSODE (void);
+
+  LSODE (int n);
+  
+  LSODE (const ColumnVector& state, double time, const ODEFunc& f);
+
+  ~LSODE (void);
+
+  void force_restart (void);
+
+  void set_stop_time (double t);
+  void clear_stop_time (void);
+
+  ColumnVector do_integrate (double t);
+
+  Matrix do_integrate (const ColumnVector& tout);
+
+#if 0
+  void integrate (int nsteps, double tstep, ostream& s);
+#endif
+
+  Matrix integrate (const ColumnVector& tout)
+    { return do_integrate (tout); }
+
+  Matrix integrate (const ColumnVector& tout, const ColumnVector& tcrit);
+
+private:
+
+  double stop_time;
+  int stop_time_set;
+
+  int n;
+  int integration_error;
+  int restart;
+  int method_flag;
+  int *iwork;
+  double *rwork;
+  int istate;
+  int itol;
+  int itask;
+  int iopt;
+  int liw;
+  int lrw;
+
+  friend int lsode_f (int *neq, double *t, double *y, double *ydot);
+
+  friend int lsode_j (int *neq, double *t, double *y, int *ml, int *mu,
+		      double *pd, int *nrowpd);
+};
+
+#endif
+
+/*
+;;; Local Variables: ***
+;;; mode: C++ ***
+;;; page-delimiter: "^/\\*" ***
+;;; End: ***
+*/