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+// tc-fsolve.cc                                           -*- C++ -*-
+/*
+
+Copyright (C) 1993 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, 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+#ifdef __GNUG__
+#pragma implementation
+#endif
+
+#include "NLEqn.h"
+
+#include "tree-const.h"
+#include "variables.h"
+#include "gripes.h"
+#include "error.h"
+#include "utils.h"
+
+// Global pointer for user defined function required by hybrd1.
+static tree *fsolve_fcn;
+
+#ifdef WITH_DLD
+tree_constant *
+builtin_fsolve (tree_constant *args, int nargin, int nargout)
+{
+  return fsolve (args, nargin, nargout);
+}
+#endif
+
+int
+hybrd_info_to_fsolve_info (int info)
+{
+  switch (info)
+    {
+    case 0:
+      info = -1;
+      break;
+    case 1:
+      break;
+    case 2:
+      info = 4;
+      break;
+    case 3:
+    case 4:
+    case 5:
+      info = 3;
+      break;
+    default:
+      panic_impossible ();
+      break;
+    }
+  return info;
+}
+
+ColumnVector
+fsolve_user_function (ColumnVector& x)
+{
+  ColumnVector retval;
+
+  int n = x.capacity ();
+
+//  tree_constant name = tree_constant (fsolve_fcn->name ());
+  tree_constant *args = new tree_constant [2];
+//  args[0] = name;
+
+  if (n > 1)
+    {
+      Matrix m (n, 1);
+      for (int i = 0; i < n; i++)
+	m (i, 0) = x.elem (i);
+      tree_constant vars (m);
+      args[1] = vars;
+    }
+  else
+    {
+      double d = x.elem (0);
+      tree_constant vars (d);
+      args[1] = vars;
+    }
+
+  if (fsolve_fcn != NULL_TREE)
+    {
+      tree_constant *tmp = fsolve_fcn->eval (args, 2, 1, 0);
+      delete [] args;
+      if (tmp != NULL_TREE_CONST && tmp[0].is_defined ())
+	{
+	  retval = tmp[0].to_vector ();
+	  delete [] tmp;
+	}
+      else
+	{
+	  delete [] tmp;
+	  gripe_user_supplied_eval ("fsolve");
+	  jump_to_top_level ();
+	}
+    }
+
+  return retval;
+}
+
+tree_constant *
+fsolve (tree_constant *args, int nargin, int nargout)
+{
+// Assumes that we have been given the correct number of arguments.
+
+  tree_constant *retval = NULL_TREE_CONST;
+
+  fsolve_fcn = is_valid_function (args[1], "fsolve", 1);
+  if (fsolve_fcn == NULL_TREE
+      || takes_correct_nargs (fsolve_fcn, 2, "fsolve", 1) != 1)
+    return retval;
+
+  ColumnVector x = args[2].to_vector ();
+
+  if (nargin > 3)
+    message ("fsolve", "ignoring optional arguments...");
+
+  if (nargout > 2)
+    message ("fsolve", "can't compute path output yet...");
+
+  NLFunc foo_fcn (fsolve_user_function);
+  NLEqn foo (x, foo_fcn);
+
+  int info;
+  ColumnVector soln = foo.solve (info);
+
+  info = hybrd_info_to_fsolve_info (info);
+
+  retval = new tree_constant [nargout+1];
+  retval[0] = tree_constant (soln, 1);
+
+  if (nargout > 1)
+    retval[1] = tree_constant ((double) info);
+
+  if (nargout > 2)
+    retval[2] = tree_constant ();
+
+  return retval;
+}
+
+/*
+;;; Local Variables: ***
+;;; mode: C++ ***
+;;; page-delimiter: "^/\\*" ***
+;;; End: ***
+*/
+