new file mode 100644
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+++ b/liboctave/fDiagMatrix.cc
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+// FloatDiagMatrix manipulations.
+/*
+
+Copyright (C) 1994, 1995, 1996, 1997, 2000, 2001, 2002, 2003, 2004,
+              2005, 2007 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 3 of the License, 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, see
+<http://www.gnu.org/licenses/>.
+
+*/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <iostream>
+
+#include "Array-util.h"
+#include "lo-error.h"
+#include "mx-base.h"
+#include "mx-inlines.cc"
+#include "oct-cmplx.h"
+
+// Diagonal Matrix class.
+
+bool
+FloatDiagMatrix::operator == (const FloatDiagMatrix& a) const
+{
+  if (rows () != a.rows () || cols () != a.cols ())
+    return 0;
+
+  return mx_inline_equal (data (), a.data (), length ());
+}
+
+bool
+FloatDiagMatrix::operator != (const FloatDiagMatrix& a) const
+{
+  return !(*this == a);
+}
+
+FloatDiagMatrix&
+FloatDiagMatrix::fill (float val)
+{
+  for (octave_idx_type i = 0; i < length (); i++)
+    elem (i, i) = val;
+  return *this;
+}
+
+FloatDiagMatrix&
+FloatDiagMatrix::fill (float val, octave_idx_type beg, octave_idx_type end)
+{
+  if (beg < 0 || end >= length () || end < beg)
+    {
+      (*current_liboctave_error_handler) ("range error for fill");
+      return *this;
+    }
+
+  for (octave_idx_type i = beg; i <= end; i++)
+    elem (i, i) = val;
+
+  return *this;
+}
+
+FloatDiagMatrix&
+FloatDiagMatrix::fill (const FloatColumnVector& a)
+{
+  octave_idx_type len = length ();
+  if (a.length () != len)
+    {
+      (*current_liboctave_error_handler) ("range error for fill");
+      return *this;
+    }
+
+  for (octave_idx_type i = 0; i < len; i++)
+    elem (i, i) = a.elem (i);
+
+  return *this;
+}
+
+FloatDiagMatrix&
+FloatDiagMatrix::fill (const FloatRowVector& a)
+{
+  octave_idx_type len = length ();
+  if (a.length () != len)
+    {
+      (*current_liboctave_error_handler) ("range error for fill");
+      return *this;
+    }
+
+  for (octave_idx_type i = 0; i < len; i++)
+    elem (i, i) = a.elem (i);
+
+  return *this;
+}
+
+FloatDiagMatrix&
+FloatDiagMatrix::fill (const FloatColumnVector& a, octave_idx_type beg)
+{
+  octave_idx_type a_len = a.length ();
+  if (beg < 0 || beg + a_len >= length ())
+    {
+      (*current_liboctave_error_handler) ("range error for fill");
+      return *this;
+    }
+
+  for (octave_idx_type i = 0; i < a_len; i++)
+    elem (i+beg, i+beg) = a.elem (i);
+
+  return *this;
+}
+
+FloatDiagMatrix&
+FloatDiagMatrix::fill (const FloatRowVector& a, octave_idx_type beg)
+{
+  octave_idx_type a_len = a.length ();
+  if (beg < 0 || beg + a_len >= length ())
+    {
+      (*current_liboctave_error_handler) ("range error for fill");
+      return *this;
+    }
+
+  for (octave_idx_type i = 0; i < a_len; i++)
+    elem (i+beg, i+beg) = a.elem (i);
+
+  return *this;
+}
+
+FloatDiagMatrix
+real (const FloatComplexDiagMatrix& a)
+{
+  FloatDiagMatrix retval;
+  octave_idx_type a_len = a.length ();
+  if (a_len > 0)
+    retval = FloatDiagMatrix (mx_inline_real_dup (a.data (), a_len), a.rows (),
+			 a.cols ());
+  return retval;
+}
+
+FloatDiagMatrix
+imag (const FloatComplexDiagMatrix& a)
+{
+  FloatDiagMatrix retval;
+  octave_idx_type a_len = a.length ();
+  if (a_len > 0)
+    retval = FloatDiagMatrix (mx_inline_imag_dup (a.data (), a_len), a.rows (),
+			 a.cols ());
+  return retval;
+}
+
+FloatMatrix
+FloatDiagMatrix::extract (octave_idx_type r1, octave_idx_type c1, octave_idx_type r2, octave_idx_type c2) const
+{
+  if (r1 > r2) { octave_idx_type tmp = r1; r1 = r2; r2 = tmp; }
+  if (c1 > c2) { octave_idx_type tmp = c1; c1 = c2; c2 = tmp; }
+
+  octave_idx_type new_r = r2 - r1 + 1;
+  octave_idx_type new_c = c2 - c1 + 1;
+
+  FloatMatrix result (new_r, new_c);
+
+  for (octave_idx_type j = 0; j < new_c; j++)
+    for (octave_idx_type i = 0; i < new_r; i++)
+      result.elem (i, j) = elem (r1+i, c1+j);
+
+  return result;
+}
+
+// extract row or column i.
+
+FloatRowVector
+FloatDiagMatrix::row (octave_idx_type i) const
+{
+  octave_idx_type r = rows ();
+  octave_idx_type c = cols ();
+  if (i < 0 || i >= r)
+    {
+      (*current_liboctave_error_handler) ("invalid row selection");
+      return FloatRowVector (); 
+    }
+
+  FloatRowVector retval (c, 0.0);
+  if (r <= c || (r > c && i < c))
+    retval.elem (i) = elem (i, i);
+
+  return retval;
+}
+
+FloatRowVector
+FloatDiagMatrix::row (char *s) const
+{
+  if (! s)
+    {
+      (*current_liboctave_error_handler) ("invalid row selection");
+      return FloatRowVector (); 
+    }
+
+  char c = *s;
+  if (c == 'f' || c == 'F')
+    return row (static_cast<octave_idx_type>(0));
+  else if (c == 'l' || c == 'L')
+    return row (rows () - 1);
+  else
+    {
+      (*current_liboctave_error_handler) ("invalid row selection");
+      return FloatRowVector (); 
+    }
+}
+
+FloatColumnVector
+FloatDiagMatrix::column (octave_idx_type i) const
+{
+  octave_idx_type r = rows ();
+  octave_idx_type c = cols ();
+  if (i < 0 || i >= c)
+    {
+      (*current_liboctave_error_handler) ("invalid column selection");
+      return FloatColumnVector (); 
+    }
+
+  FloatColumnVector retval (r, 0.0);
+  if (r >= c || (r < c && i < r))
+    retval.elem (i) = elem (i, i);
+
+  return retval;
+}
+
+FloatColumnVector
+FloatDiagMatrix::column (char *s) const
+{
+  if (! s)
+    {
+      (*current_liboctave_error_handler) ("invalid column selection");
+      return FloatColumnVector (); 
+    }
+
+  char c = *s;
+  if (c == 'f' || c == 'F')
+    return column (static_cast<octave_idx_type>(0));
+  else if (c == 'l' || c == 'L')
+    return column (cols () - 1);
+  else
+    {
+      (*current_liboctave_error_handler) ("invalid column selection");
+      return FloatColumnVector (); 
+    }
+}
+
+FloatDiagMatrix
+FloatDiagMatrix::inverse (void) const
+{
+  int info;
+  return inverse (info);
+}
+
+FloatDiagMatrix
+FloatDiagMatrix::inverse (int &info) const
+{
+  octave_idx_type r = rows ();
+  octave_idx_type c = cols ();
+  octave_idx_type len = length ();
+  if (r != c)
+    {
+      (*current_liboctave_error_handler) ("inverse requires square matrix");
+      return FloatDiagMatrix ();
+    }
+
+  FloatDiagMatrix retval (r, c);
+
+  info = 0;
+  for (octave_idx_type i = 0; i < len; i++)
+    {
+      if (elem (i, i) == 0.0)
+	{
+	  info = -1;
+	  return *this;
+	}
+      else
+	retval.elem (i, i) = 1.0 / elem (i, i);
+    }
+
+  return retval;
+}
+
+// diagonal matrix by diagonal matrix -> diagonal matrix operations
+
+// diagonal matrix by diagonal matrix -> diagonal matrix operations
+
+FloatDiagMatrix
+operator * (const FloatDiagMatrix& a, const FloatDiagMatrix& b)
+{
+  octave_idx_type a_nr = a.rows ();
+  octave_idx_type a_nc = a.cols ();
+
+  octave_idx_type b_nr = b.rows ();
+  octave_idx_type b_nc = b.cols ();
+
+  if (a_nc != b_nr)
+    {
+      gripe_nonconformant ("operaotr *", a_nr, a_nc, b_nr, b_nc);
+      return FloatDiagMatrix ();
+    }
+
+  if (a_nr == 0 || a_nc == 0 || b_nc == 0)
+    return FloatDiagMatrix (a_nr, a_nc, 0.0);
+
+  FloatDiagMatrix c (a_nr, b_nc);
+
+  octave_idx_type len = a_nr < b_nc ? a_nr : b_nc;
+
+  for (octave_idx_type i = 0; i < len; i++)
+    {
+      float a_element = a.elem (i, i);
+      float b_element = b.elem (i, i);
+
+      if (a_element == 0.0 || b_element == 0.0)
+        c.elem (i, i) = 0.0;
+      else if (a_element == 1.0)
+        c.elem (i, i) = b_element;
+      else if (b_element == 1.0)
+        c.elem (i, i) = a_element;
+      else
+        c.elem (i, i) = a_element * b_element;
+    }
+
+  return c;
+}
+
+// other operations
+
+FloatColumnVector
+FloatDiagMatrix::diag (octave_idx_type k) const
+{
+  octave_idx_type nnr = rows ();
+  octave_idx_type nnc = cols ();
+
+  if (nnr == 0  || nnc == 0)
+    
+  if (k > 0)
+    nnc -= k;
+  else if (k < 0)
+    nnr += k;
+
+  FloatColumnVector d;
+
+  if (nnr > 0 && nnc > 0)
+    {
+      octave_idx_type ndiag = (nnr < nnc) ? nnr : nnc;
+
+      d.resize (ndiag);
+
+      if (k > 0)
+	{
+	  for (octave_idx_type i = 0; i < ndiag; i++)
+	    d.elem (i) = elem (i, i+k);
+	}
+      else if ( k < 0)
+	{
+	  for (octave_idx_type i = 0; i < ndiag; i++)
+	    d.elem (i) = elem (i-k, i);
+	}
+      else
+	{
+	  for (octave_idx_type i = 0; i < ndiag; i++)
+	    d.elem (i) = elem (i, i);
+	}
+    }
+  else
+    (*current_liboctave_error_handler)
+      ("diag: requested diagonal out of range");
+
+  return d;
+}
+
+std::ostream&
+operator << (std::ostream& os, const FloatDiagMatrix& a)
+{
+//  int field_width = os.precision () + 7;
+
+  for (octave_idx_type i = 0; i < a.rows (); i++)
+    {
+      for (octave_idx_type j = 0; j < a.cols (); j++)
+	{
+	  if (i == j)
+	    os << " " /* setw (field_width) */ << a.elem (i, i);
+	  else
+	    os << " " /* setw (field_width) */ << 0.0;
+	}
+      os << "\n";
+    }
+  return os;
+}
+
+/*
+;;; Local Variables: ***
+;;; mode: C++ ***
+;;; End: ***
+*/