new file mode 100644
--- /dev/null
+++ b/src/sparse-xpow.cc
@@ -0,0 +1,795 @@
+/*
+
+Copyright (C) 2004 David Bateman
+Copyright (C) 1998-2004 Andy Adler
+
+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 this program; see the file COPYING.  If not, write to the Free
+Software Foundation, 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+
+*/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <cassert>
+#include <climits>
+
+#include "Array-util.h"
+#include "oct-cmplx.h"
+#include "quit.h"
+
+#include "error.h"
+#include "oct-obj.h"
+#include "utils.h"
+
+#include "dSparse.h"
+#include "CSparse.h"
+#include "ov-re-sparse.h"
+#include "ov-cx-sparse.h"
+#include "sparse-xpow.h"
+
+static inline int
+xisint (double x)
+{
+  return (D_NINT (x) == x
+	  && ((x >= 0 && x < INT_MAX)
+	      || (x <= 0 && x > INT_MIN)));
+}
+
+
+// Safer pow functions. Only two make sense for sparse matrices, the
+// others should all promote to full matrices.
+
+octave_value
+xpow (const SparseMatrix& a, double b)
+{
+  octave_value retval;
+
+  int nr = a.rows ();
+  int nc = a.cols ();
+
+  if (nr == 0 || nc == 0 || nr != nc)
+    error ("for A^b, A must be square");
+  else
+    {
+      if (static_cast<int> (b) == b)
+	{
+	  int btmp = static_cast<int> (b);
+	  if (btmp == 0)
+	    {
+	      SparseMatrix tmp = SparseMatrix (nr, nr, nr);
+	      for (int i = 0; i < nr; i++)
+		{
+		  tmp.data (i) = 1.0;
+		  tmp.ridx (i) = i;
+		}
+	      for (int i = 0; i < nr + 1; i++)
+		tmp.cidx (i) = i;
+
+	      retval = tmp;
+	    }
+	  else
+	    {
+	      SparseMatrix atmp;
+	      if (btmp < 0)
+		{
+		  btmp = -btmp;
+
+		  int info;
+		  double rcond = 0.0;
+
+		  atmp = a.inverse (info, rcond, 1);
+
+		  if (info == -1)
+		    warning ("inverse: matrix singular to machine\
+ precision, rcond = %g", rcond);
+		}
+	      else
+		atmp = a;
+
+	      SparseMatrix result (atmp);
+
+	      btmp--;
+
+	      while (btmp > 0)
+		{
+		  if (btmp & 1)
+		    result = result * atmp;
+
+		  btmp >>= 1;
+
+		  if (btmp > 0)
+		    atmp = atmp * atmp;
+		}
+
+	      retval = result;
+	    }
+	}
+      else
+	error ("use full(a) ^ full(b)");
+    }
+
+  return retval;
+}
+
+octave_value
+xpow (const SparseComplexMatrix& a, double b)
+{
+  octave_value retval;
+
+  int nr = a.rows ();
+  int nc = a.cols ();
+
+  if (nr == 0 || nc == 0 || nr != nc)
+    error ("for A^b, A must be square");
+  else
+    {
+      if (static_cast<int> (b) == b)
+	{
+	  int btmp = static_cast<int> (b);
+	  if (btmp == 0)
+	    {
+	      SparseMatrix tmp = SparseMatrix (nr, nr, nr);
+	      for (int i = 0; i < nr; i++)
+		{
+		  tmp.data (i) = 1.0;
+		  tmp.ridx (i) = i;
+		}
+	      for (int i = 0; i < nr + 1; i++)
+		tmp.cidx (i) = i;
+
+	      retval = tmp;
+	    }
+	  else
+	    {
+	      SparseComplexMatrix atmp;
+	      if (btmp < 0)
+		{
+		  btmp = -btmp;
+
+		  int info;
+		  double rcond = 0.0;
+
+		  atmp = a.inverse (info, rcond, 1);
+
+		  if (info == -1)
+		    warning ("inverse: matrix singular to machine\
+ precision, rcond = %g", rcond);
+		}
+	      else
+		atmp = a;
+
+	      SparseComplexMatrix result (atmp);
+
+	      btmp--;
+
+	      while (btmp > 0)
+		{
+		  if (btmp & 1)
+		    result = result * atmp;
+
+		  btmp >>= 1;
+
+		  if (btmp > 0)
+		    atmp = atmp * atmp;
+		}
+
+	      retval = result;
+	    }
+	}
+      else
+	error ("use full(a) ^ full(b)");
+    }
+
+  return retval;
+}
+
+// Safer pow functions that work elementwise for matrices.
+//
+//       op2 \ op1:   s   m   cs   cm
+//            +--   +---+---+----+----+
+//   scalar   |     | * | 3 |  * |  9 |
+//                  +---+---+----+----+
+//   matrix         | 1 | 4 |  7 | 10 |
+//                  +---+---+----+----+
+//   complex_scalar | * | 5 |  * | 11 |
+//                  +---+---+----+----+
+//   complex_matrix | 2 | 6 |  8 | 12 |
+//                  +---+---+----+----+
+//
+//   * -> not needed.
+
+// XXX FIXME XXX -- these functions need to be fixed so that things
+// like
+//
+//   a = -1; b = [ 0, 0.5, 1 ]; r = a .^ b
+//
+// and
+//
+//   a = -1; b = [ 0, 0.5, 1 ]; for i = 1:3, r(i) = a .^ b(i), end
+//
+// produce identical results.  Also, it would be nice if -1^0.5
+// produced a pure imaginary result instead of a complex number with a
+// small real part.  But perhaps that's really a problem with the math
+// library...
+
+// -*- 1 -*-
+octave_value
+elem_xpow (double a, const SparseMatrix& b)
+{
+  octave_value retval;
+
+  int nr = b.rows ();
+  int nc = b.cols ();
+
+  double d1, d2;
+
+  if (a < 0.0 && ! b.all_integers (d1, d2))
+    {
+      Complex atmp (a);
+      ComplexMatrix result (nr, nc);
+
+      for (int j = 0; j < nc; j++)
+	{
+	  for (int i = 0; i < nr; i++)
+	    {
+	      OCTAVE_QUIT;
+	      result (i, j) = pow (atmp, b(i,j));
+	    }
+	}
+
+      retval = result;
+    }
+  else
+    {
+      Matrix result (nr, nc);
+
+      for (int j = 0; j < nc; j++)
+	{
+	  for (int i = 0; i < nr; i++)
+	    {
+	      OCTAVE_QUIT;
+	      result (i, j) = pow (a, b(i,j));
+	    }
+	}
+
+      retval = result;
+    }
+
+  return retval;
+}
+
+// -*- 2 -*-
+octave_value
+elem_xpow (double a, const SparseComplexMatrix& b)
+{
+  int nr = b.rows ();
+  int nc = b.cols ();
+
+  Complex atmp (a);
+  ComplexMatrix result (nr, nc);
+
+  for (int j = 0; j < nc; j++)
+    {
+      for (int i = 0; i < nr; i++)
+	{
+	  OCTAVE_QUIT;
+	  result (i, j) = pow (atmp, b(i,j));
+	}
+    }
+
+  return result;
+}
+
+// -*- 3 -*-
+octave_value
+elem_xpow (const SparseMatrix& a, double b)
+{
+  // XXX FIXME XXX What should a .^ 0 give?? Matlab gives a 
+  // sparse matrix with same structure as a, which is strictly
+  // incorrect. Keep compatiability.
+
+  octave_value retval;
+
+  int nz = a.nnz ();
+
+  if (b <= 0.0)
+    {
+      int nr = a.rows ();
+      int nc = a.cols ();
+
+      if (static_cast<int> (b) != b && a.any_element_is_negative ())
+	{
+	  ComplexMatrix result (nr, nc, Complex (pow (0.0, b)));
+
+	  // XXX FIXME XXX -- avoid apparent GNU libm bug by
+	  // converting A and B to complex instead of just A.
+	  Complex btmp (b);
+
+	  for (int j = 0; j < nc; j++)
+	    for (int i = a.cidx(j); i < a.cidx(j+1); i++)
+	      {
+		OCTAVE_QUIT;
+	      
+		Complex atmp (a.data (i));
+		
+		result (a.ridx(i), j) = pow (atmp, btmp);
+	      }
+
+	  retval = octave_value (result);
+	}
+      else
+	{
+	  Matrix result (nr, nc, (pow (0.0, b)));
+
+	  for (int j = 0; j < nc; j++)
+	    for (int i = a.cidx(j); i < a.cidx(j+1); i++)
+	      {
+		OCTAVE_QUIT;
+		result (a.ridx(i), j) = pow (a.data (i), b);
+	      }
+
+	  retval = octave_value (result);
+	}
+    }
+  else if (static_cast<int> (b) != b && a.any_element_is_negative ())
+    {
+      SparseComplexMatrix result (a);
+
+      for (int i = 0; i < nz; i++)
+	{
+	  OCTAVE_QUIT;
+
+	  // XXX FIXME XXX -- avoid apparent GNU libm bug by
+	  // converting A and B to complex instead of just A.
+
+	  Complex atmp (a.data (i));
+	  Complex btmp (b);
+
+	  result.data (i) = pow (atmp, btmp);
+	}
+
+      result.maybe_compress (true);
+
+      retval = result;
+    }
+  else
+    {
+      SparseMatrix result (a);
+
+      for (int i = 0; i < nz; i++)
+	{
+	  OCTAVE_QUIT;
+	  result.data (i) = pow (a.data (i), b);
+	}
+
+      result.maybe_compress (true);
+
+      retval = result;
+    }
+
+  return retval;
+}
+
+// -*- 4 -*-
+octave_value
+elem_xpow (const SparseMatrix& a, const SparseMatrix& b)
+{
+  octave_value retval;
+
+  int nr = a.rows ();
+  int nc = a.cols ();
+
+  int b_nr = b.rows ();
+  int b_nc = b.cols ();
+
+  if (nr != b_nr || nc != b_nc)
+    {
+      gripe_nonconformant ("operator .^", nr, nc, b_nr, b_nc);
+      return octave_value ();
+    }
+
+  int convert_to_complex = 0;
+  for (int j = 0; j < nc; j++)
+    for (int i = 0; i < nr; i++)
+      {
+	OCTAVE_QUIT;
+	double atmp = a (i, j);
+	double btmp = b (i, j);
+	if (atmp < 0.0 && static_cast<int> (btmp) != btmp)
+	  {
+	    convert_to_complex = 1;
+	    goto done;
+	  }
+      }
+
+done:
+
+  int nel = 0;
+  for (int j = 0; j < nc; j++) 
+    for (int i = 0; i < nr; i++)
+      if (!(a.elem (i, j) == 0. && b.elem (i, j) != 0.))
+	nel++;
+
+  if (convert_to_complex)
+    {
+      SparseComplexMatrix complex_result (nr, nc, nel);
+
+      int ii = 0;
+      complex_result.cidx(0) = 0;
+      for (int j = 0; j < nc; j++)
+	{
+	  for (int i = 0; i < nr; i++)
+	    {
+	      OCTAVE_QUIT;
+	      Complex atmp (a (i, j));
+	      Complex btmp (b (i, j));
+	      Complex tmp =  pow (atmp, btmp);
+	      if (tmp != 0.)
+		{
+		  complex_result.data (ii) = tmp;
+		  complex_result.ridx (ii++) = i;
+		}
+	    }
+	  complex_result.cidx (j+1) = ii;
+	}
+      complex_result.maybe_compress ();
+
+      retval = complex_result;
+    }
+  else
+    {
+      SparseMatrix result (nr, nc, nel);
+      int ii = 0;
+
+      result.cidx (0) = 0;
+      for (int j = 0; j < nc; j++)
+	{
+	  for (int i = 0; i < nr; i++)
+	    {
+	      OCTAVE_QUIT;
+	      double tmp = pow (a (i, j), b (i, j));
+	      if (tmp != 0.)
+		{
+		  result.data (ii) = tmp;
+		  result.ridx (ii++) = i;
+		}
+	    }
+	  result.cidx (j+1) = ii;
+	}
+
+      result.maybe_compress ();
+
+      retval = result;
+    }
+
+  return retval;
+}
+
+// -*- 5 -*-
+octave_value
+elem_xpow (const SparseMatrix& a, const Complex& b)
+{
+  octave_value retval;
+
+  if (b == 0.0)
+    // Can this case ever happen, due to automatic retyping with maybe_mutate?
+    retval = octave_value (NDArray (a.dims (), 1));
+  else
+    {
+      int nz = a.nnz ();
+      SparseComplexMatrix result (a);
+      
+      for (int i = 0; i < nz; i++)
+	{
+	  OCTAVE_QUIT;
+	  result.data (i) = pow (Complex (a.data (i)), b);
+	}
+  
+      result.maybe_compress (true);
+
+      retval = result;
+    }
+
+  return retval;
+}
+
+// -*- 6 -*-
+octave_value
+elem_xpow (const SparseMatrix& a, const SparseComplexMatrix& b)
+{
+  int nr = a.rows ();
+  int nc = a.cols ();
+
+  int b_nr = b.rows ();
+  int b_nc = b.cols ();
+
+  if (nr != b_nr || nc != b_nc)
+    {
+      gripe_nonconformant ("operator .^", nr, nc, b_nr, b_nc);
+      return octave_value ();
+    }
+
+  int nel = 0;
+  for (int j = 0; j < nc; j++) 
+    for (int i = 0; i < nr; i++)
+      if (!(a.elem (i, j) == 0. && b.elem (i, j) != 0.))
+	nel++;
+
+  SparseComplexMatrix result (nr, nc, nel);
+  int ii = 0;
+
+  result.cidx(0) = 0;
+  for (int j = 0; j < nc; j++)
+    {
+      for (int i = 0; i < nr; i++)
+	{
+	  OCTAVE_QUIT;
+	  Complex tmp = pow (Complex (a (i, j)), b (i, j));
+	  if (tmp != 0.)
+	    {
+	      result.data (ii) = tmp; 
+	      result.ridx (ii++) = i; 
+	    }
+	}
+      result.cidx (j+1) = ii;
+    }
+
+  result.maybe_compress ();
+
+  return result;
+}
+
+// -*- 7 -*-
+octave_value
+elem_xpow (const Complex& a, const SparseMatrix& b)
+{
+  int nr = b.rows ();
+  int nc = b.cols ();
+
+  ComplexMatrix result (nr, nc);
+
+  for (int j = 0; j < nc; j++)
+    {
+      for (int i = 0; i < nr; i++)
+	{
+	  OCTAVE_QUIT;
+	  double btmp = b (i, j);
+	  if (xisint (btmp))
+	    result (i, j) = pow (a, static_cast<int> (btmp));
+	  else
+	    result (i, j) = pow (a, btmp);
+	}
+    }
+
+  return result;
+}
+
+// -*- 8 -*-
+octave_value
+elem_xpow (const Complex& a, const SparseComplexMatrix& b)
+{
+  int nr = b.rows ();
+  int nc = b.cols ();
+
+  ComplexMatrix result (nr, nc);
+  for (int j = 0; j < nc; j++)
+    for (int i = 0; i < nr; i++)
+      {
+	OCTAVE_QUIT;
+	result (i, j) = pow (a, b (i, j));
+      }
+
+  return result;
+}
+
+// -*- 9 -*-
+octave_value
+elem_xpow (const SparseComplexMatrix& a, double b)
+{
+  octave_value retval;
+
+  if (b <= 0)
+    {
+      int nr = a.rows ();
+      int nc = a.cols ();
+
+      ComplexMatrix result (nr, nc, Complex (pow (0.0, b)));
+
+      if (xisint (b))
+	{
+	  for (int j = 0; j < nc; j++)
+	    for (int i = a.cidx(j); i < a.cidx(j+1); i++)
+	      {
+		OCTAVE_QUIT;
+		result (a.ridx(i), j) = 
+		  pow (a.data (i), static_cast<int> (b));
+	      }
+	}
+      else
+	{
+	  for (int j = 0; j < nc; j++)
+	    for (int i = a.cidx(j); i < a.cidx(j+1); i++)
+	      {
+		OCTAVE_QUIT;
+		result (a.ridx(i), j) = pow (a.data (i), b);
+	      }
+	}  
+
+      retval = result;
+    }
+  else
+    {
+      int nz = a.nnz ();
+
+      SparseComplexMatrix result (a);
+  
+      if (xisint (b))
+	{
+	  for (int i = 0; i < nz; i++)
+	    {
+	      OCTAVE_QUIT;
+	      result.data (i) = pow (a.data (i), static_cast<int> (b));
+	    }
+	}
+      else
+	{
+	  for (int i = 0; i < nz; i++)
+	    {
+	      OCTAVE_QUIT;
+	      result.data (i) = pow (a.data (i), b);
+	    }
+	}  
+
+      result.maybe_compress (true);
+
+      retval = result;
+    }
+
+  return retval;
+}
+
+// -*- 10 -*-
+octave_value
+elem_xpow (const SparseComplexMatrix& a, const SparseMatrix& b)
+{
+  int nr = a.rows ();
+  int nc = a.cols ();
+
+  int b_nr = b.rows ();
+  int b_nc = b.cols ();
+
+  if (nr != b_nr || nc != b_nc)
+    {
+      gripe_nonconformant ("operator .^", nr, nc, b_nr, b_nc);
+      return octave_value ();
+    }
+
+  int nel = 0;
+  for (int j = 0; j < nc; j++) 
+    for (int i = 0; i < nr; i++)
+      if (!(a.elem (i, j) == 0. && b.elem (i, j) != 0.))
+	nel++;
+
+  SparseComplexMatrix result (nr, nc, nel);
+  int ii = 0;
+
+  result.cidx (0) = 0;
+  for (int j = 0; j < nc; j++)
+    {
+      for (int i = 0; i < nr; i++)
+	{
+	  OCTAVE_QUIT;
+	  double btmp = b (i, j);
+	  Complex tmp;
+
+	  if (xisint (btmp))
+	    tmp = pow (a (i, j), static_cast<int> (btmp));
+	  else
+	    tmp = pow (a (i, j), btmp);
+	  if (tmp != 0.)
+	    {
+	      result.data (ii) = tmp; 
+	      result.ridx (ii++) = i; 
+	    }
+	}
+      result.cidx (j+1) = ii;
+    }
+
+  result.maybe_compress ();
+
+  return result;
+}
+
+// -*- 11 -*-
+octave_value
+elem_xpow (const SparseComplexMatrix& a, const Complex& b)
+{
+  octave_value retval;
+
+  if (b == 0.0)
+    // Can this case ever happen, due to automatic retyping with maybe_mutate?
+    retval = octave_value (NDArray (a.dims (), 1));
+  else
+    {
+
+      int nz = a.nnz ();
+
+      SparseComplexMatrix result (a);
+
+      for (int i = 0; i < nz; i++)
+	{
+	  OCTAVE_QUIT;
+	  result.data (i) = pow (a.data (i), b);
+	}
+
+      result.maybe_compress (true);
+      
+      retval = result;
+    }
+
+  return retval;
+}
+
+// -*- 12 -*-
+octave_value
+elem_xpow (const SparseComplexMatrix& a, const SparseComplexMatrix& b)
+{
+  int nr = a.rows ();
+  int nc = a.cols ();
+
+  int b_nr = b.rows ();
+  int b_nc = b.cols ();
+
+  if (nr != b_nr || nc != b_nc)
+    {
+      gripe_nonconformant ("operator .^", nr, nc, b_nr, b_nc);
+      return octave_value ();
+    }
+
+  int nel = 0;
+  for (int j = 0; j < nc; j++) 
+    for (int i = 0; i < nr; i++)
+      if (!(a.elem (i, j) == 0. && b.elem (i, j) != 0.))
+	nel++;
+
+  SparseComplexMatrix result (nr, nc, nel);
+  int ii = 0;
+
+  result.cidx (0) = 0;
+  for (int j = 0; j < nc; j++) 
+    {
+      for (int i = 0; i < nr; i++)
+	{
+	  OCTAVE_QUIT;
+	  Complex tmp = pow (a (i, j), b (i, j));
+	  if (tmp != 0.)
+	    {
+	      result.data (ii) = tmp;
+	      result.ridx (ii++) = i;
+	    }
+	}
+      result.cidx (j+1) = ii;
+    }
+  result.maybe_compress (true);
+
+  return result;
+}
+
+/*
+;;; Local Variables: ***
+;;; mode: C++ ***
+;;; End: ***
+*/