new file mode 100644
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+++ b/liboctave/dDiagMatrix.h
@@ -0,0 +1,189 @@
+//                                  -*- C++ -*-
+/*
+
+Copyright (C) 1992, 1993, 1994 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.
+
+*/
+
+#if !defined (octave_DiagMatrix_h)
+#define octave_DiagMatrix_h 1
+
+#if defined (__GNUG__)
+#pragma interface
+#endif
+
+#include "Array.h"
+
+#include "dRowVector.h"
+#include "dColVector.h"
+
+#include "mx-defs.h"
+
+extern "C++" {
+
+class DiagMatrix : public DiagArray<double>
+{
+friend class SVD;
+friend class ComplexSVD;
+
+public:
+
+  DiagMatrix (void) : DiagArray<double> () { }
+  DiagMatrix (int n) : DiagArray<double> (n) { }
+  DiagMatrix (int n, double val) : DiagArray<double> (n, val) { }
+  DiagMatrix (int r, int c) : DiagArray<double> (r, c) { }
+  DiagMatrix (int r, int c, double val) : DiagArray<double> (r, c, val) { }
+  DiagMatrix (const RowVector& a) : DiagArray<double> (a) { }
+  DiagMatrix (const ColumnVector& a) : DiagArray<double> (a) { }
+  DiagMatrix (const DiagArray<double>& a) : DiagArray<double> (a) { }
+  DiagMatrix (const DiagMatrix& a) : DiagArray<double> (a) { }
+//  DiagMatrix (double a) : DiagArray<double> (1, a) { }
+
+  DiagMatrix& operator = (const DiagMatrix& a)
+    {
+      DiagArray<double>::operator = (a);
+      return *this;
+    }
+
+//  operator DiagArray<double>& () const { return *this; }
+
+  int operator == (const DiagMatrix& a) const;
+  int operator != (const DiagMatrix& a) const;
+
+  DiagMatrix& fill (double val);
+  DiagMatrix& fill (double val, int beg, int end);
+  DiagMatrix& fill (const ColumnVector& a);
+  DiagMatrix& fill (const RowVector& a);
+  DiagMatrix& fill (const ColumnVector& a, int beg);
+  DiagMatrix& fill (const RowVector& a, int beg);
+
+  DiagMatrix transpose (void) const;
+
+// resize is the destructive analog for this one
+
+  Matrix extract (int r1, int c1, int r2, int c2) const;
+
+// extract row or column i.
+
+  RowVector row (int i) const;
+  RowVector row (char *s) const;
+
+  ColumnVector column (int i) const;
+  ColumnVector column (char *s) const;
+
+  DiagMatrix inverse (void) const;
+  DiagMatrix inverse (int& info) const;
+
+// diagonal matrix by diagonal matrix -> diagonal matrix operations
+
+  DiagMatrix& operator += (const DiagMatrix& a);
+  DiagMatrix& operator -= (const DiagMatrix& a);
+
+// diagonal matrix by scalar -> matrix operations
+
+  friend Matrix operator + (const DiagMatrix& a, double s);
+  friend Matrix operator - (const DiagMatrix& a, double s);
+
+  friend ComplexMatrix operator + (const DiagMatrix& a, const Complex& s);
+  friend ComplexMatrix operator - (const DiagMatrix& a, const Complex& s);
+
+// diagonal matrix by scalar -> diagonal matrix operations
+
+  friend ComplexDiagMatrix operator * (const DiagMatrix& a, const Complex& s);
+  friend ComplexDiagMatrix operator / (const DiagMatrix& a, const Complex& s);
+
+// scalar by diagonal matrix -> matrix operations
+
+  friend Matrix operator + (double s, const DiagMatrix& a);
+  friend Matrix operator - (double s, const DiagMatrix& a);
+
+  friend ComplexMatrix operator + (const Complex& s, const DiagMatrix& a);
+  friend ComplexMatrix operator - (const Complex& s, const DiagMatrix& a);
+
+// scalar by diagonal matrix -> diagonal matrix operations
+
+  friend ComplexDiagMatrix operator * (const Complex& s, const DiagMatrix& a);
+
+// diagonal matrix by column vector -> column vector operations
+
+  friend ColumnVector operator * (const DiagMatrix& a, const ColumnVector& b);
+
+  friend ComplexColumnVector operator * (const DiagMatrix& a,
+					 const ComplexColumnVector& b);
+
+// diagonal matrix by diagonal matrix -> diagonal matrix operations
+
+  friend DiagMatrix operator * (const DiagMatrix& a,
+				const DiagMatrix& b);
+
+  friend ComplexDiagMatrix operator + (const DiagMatrix& a,
+				       const ComplexDiagMatrix& b);
+  friend ComplexDiagMatrix operator - (const DiagMatrix& a,
+				       const ComplexDiagMatrix& b);
+  friend ComplexDiagMatrix operator * (const DiagMatrix& a,
+				       const ComplexDiagMatrix& b);
+
+  friend ComplexDiagMatrix product (const DiagMatrix& a,
+				    const ComplexDiagMatrix& b);
+
+// diagonal matrix by matrix -> matrix operations
+
+  friend Matrix operator + (const DiagMatrix& a, const Matrix& b);
+  friend Matrix operator - (const DiagMatrix& a, const Matrix& b);
+  friend Matrix operator * (const DiagMatrix& a, const Matrix& b);
+
+  friend ComplexMatrix operator + (const DiagMatrix& a,
+				   const ComplexMatrix& b);
+  friend ComplexMatrix operator - (const DiagMatrix& a,
+				   const ComplexMatrix& b);
+  friend ComplexMatrix operator * (const DiagMatrix& a,
+				   const ComplexMatrix& b);
+
+// other operations
+
+  ColumnVector diag (void) const;
+  ColumnVector diag (int k) const;
+
+// i/o
+
+  friend ostream& operator << (ostream& os, const DiagMatrix& a);
+
+#define KLUDGE_DIAG_MATRICES
+#define TYPE double
+#define KL_DMAT_TYPE DiagMatrix
+#include "mx-kludge.h"
+#undef KLUDGE_DIAG_MATRICES
+#undef TYPE
+#undef KL_DMAT_TYPE
+
+private:
+
+  DiagMatrix (double *d, int nr, int nc) : DiagArray<double> (d, nr, nc) { }
+};
+
+} // extern "C++"
+
+#endif
+
+/*
+;;; Local Variables: ***
+;;; mode: C++ ***
+;;; page-delimiter: "^/\\*" ***
+;;; End: ***
+*/