# HG changeset patch
# User jwe
# Date 1044914235 0
# Node ID 236c10efcde2c61ff6565c8d9717e98547750c42
# Parent  0a056052bc9017014805a0629db972fe62cba3bf
[project @ 2003-02-10 21:57:15 by jwe]

diff -r 0a056052bc90 -r 236c10efcde2 liboctave/CColVector.cc
--- a/liboctave/CColVector.cc	Mon Feb 03 17:34:24 2003 +0000
+++ b/liboctave/CColVector.cc	Mon Feb 10 21:57:15 2003 +0000
@@ -78,14 +78,20 @@
 ComplexColumnVector::insert (const ColumnVector& a, int r)
 {
   int a_len = a.length ();
+
   if (r < 0 || r + a_len > length ())
     {
       (*current_liboctave_error_handler) ("range error for insert");
       return *this;
     }
 
-  for (int i = 0; i < a_len; i++)
-    elem (r+i) = a.elem (i);
+  if (a_len > 0)
+    {
+      make_unique ();
+
+      for (int i = 0; i < a_len; i++)
+	xelem (r+i) = a.elem (i);
+    }
 
   return *this;
 }
@@ -94,14 +100,20 @@
 ComplexColumnVector::insert (const ComplexColumnVector& a, int r)
 {
   int a_len = a.length ();
+
   if (r < 0 || r + a_len > length ())
     {
       (*current_liboctave_error_handler) ("range error for insert");
       return *this;
     }
 
-  for (int i = 0; i < a_len; i++)
-    elem (r+i) = a.elem (i);
+  if (a_len > 0)
+    {
+      make_unique ();
+
+      for (int i = 0; i < a_len; i++)
+	xelem (r+i) = a.elem (i);
+    }
 
   return *this;
 }
@@ -110,9 +122,15 @@
 ComplexColumnVector::fill (double val)
 {
   int len = length ();
+
   if (len > 0)
-    for (int i = 0; i < len; i++)
-      elem (i) = val;
+    {
+      make_unique ();
+
+      for (int i = 0; i < len; i++)
+	xelem (i) = val;
+    }
+
   return *this;
 }
 
@@ -120,9 +138,16 @@
 ComplexColumnVector::fill (const Complex& val)
 {
   int len = length ();
+
   if (len > 0)
-    for (int i = 0; i < len; i++)
-      elem (i) = val;
+    {
+      make_unique ();
+
+      for (int i = 0; i < len; i++)
+	xelem (i) = val;
+    }
+
+
   return *this;
 }
 
@@ -130,6 +155,7 @@
 ComplexColumnVector::fill (double val, int r1, int r2)
 {
   int len = length ();
+
   if (r1 < 0 || r2 < 0 || r1 >= len || r2 >= len)
     {
       (*current_liboctave_error_handler) ("range error for fill");
@@ -138,8 +164,13 @@
 
   if (r1 > r2) { int tmp = r1; r1 = r2; r2 = tmp; }
 
-  for (int i = r1; i <= r2; i++)
-    elem (i) = val;
+  if (r2 >= r1)
+    {
+      make_unique ();
+
+      for (int i = r1; i <= r2; i++)
+	xelem (i) = val;
+    }
 
   return *this;
 }
@@ -148,6 +179,7 @@
 ComplexColumnVector::fill (const Complex& val, int r1, int r2)
 {
   int len = length ();
+
   if (r1 < 0 || r2 < 0 || r1 >= len || r2 >= len)
     {
       (*current_liboctave_error_handler) ("range error for fill");
@@ -156,8 +188,13 @@
 
   if (r1 > r2) { int tmp = r1; r1 = r2; r2 = tmp; }
 
-  for (int i = r1; i <= r2; i++)
-    elem (i) = val;
+  if (r2 >= r1)
+    {
+      make_unique ();
+
+      for (int i = r1; i <= r2; i++)
+	xelem (i) = val;
+    }
 
   return *this;
 }
@@ -224,6 +261,17 @@
   return result;
 }
 
+ComplexColumnVector
+ComplexColumnVector::extract_n (int r1, int n) const
+{
+  ComplexColumnVector result (n);
+
+  for (int i = 0; i < n; i++)
+    result.elem (i) = elem (r1+i);
+
+  return result;
+}
+
 // column vector by column vector -> column vector operations
 
 ComplexColumnVector&
diff -r 0a056052bc90 -r 236c10efcde2 liboctave/CColVector.h
--- a/liboctave/CColVector.h	Mon Feb 03 17:34:24 2003 +0000
+++ b/liboctave/CColVector.h	Mon Feb 10 21:57:15 2003 +0000
@@ -83,6 +83,8 @@
 
   ComplexColumnVector extract (int r1, int r2) const;
 
+  ComplexColumnVector extract_n (int r1, int n) const;
+
   // column vector by column vector -> column vector operations
 
   ComplexColumnVector& operator += (const ColumnVector& a);
diff -r 0a056052bc90 -r 236c10efcde2 liboctave/CMatrix.cc
--- a/liboctave/CMatrix.cc	Mon Feb 03 17:34:24 2003 +0000
+++ b/liboctave/CMatrix.cc	Mon Feb 10 21:57:15 2003 +0000
@@ -240,9 +240,14 @@
       return *this;
     }
 
-  for (int j = 0; j < a_nc; j++)
-    for (int i = 0; i < a_nr; i++)
-      elem (r+i, c+j) = a.elem (i, j);
+  if (a_nr >0 && a_nc > 0)
+    {
+      make_unique ();
+
+      for (int j = 0; j < a_nc; j++)
+	for (int i = 0; i < a_nr; i++)
+	  xelem (r+i, c+j) = a.elem (i, j);
+    }
 
   return *this;
 }
@@ -251,14 +256,20 @@
 ComplexMatrix::insert (const RowVector& a, int r, int c)
 {
   int a_len = a.length ();
+
   if (r < 0 || r >= rows () || c < 0 || c + a_len > cols ())
     {
       (*current_liboctave_error_handler) ("range error for insert");
       return *this;
     }
 
-  for (int i = 0; i < a_len; i++)
-    elem (r, c+i) = a.elem (i);
+  if (a_len > 0)
+    {
+      make_unique ();
+
+      for (int i = 0; i < a_len; i++)
+	xelem (r, c+i) = a.elem (i);
+    }
 
   return *this;
 }
@@ -267,14 +278,20 @@
 ComplexMatrix::insert (const ColumnVector& a, int r, int c)
 {
   int a_len = a.length ();
+
   if (r < 0 || r + a_len > rows () || c < 0 || c >= cols ())
     {
       (*current_liboctave_error_handler) ("range error for insert");
       return *this;
     }
 
-  for (int i = 0; i < a_len; i++)
-    elem (r+i, c) = a.elem (i);
+  if (a_len > 0)
+    {
+      make_unique ();
+
+      for (int i = 0; i < a_len; i++)
+	xelem (r+i, c) = a.elem (i);
+    }
 
   return *this;
 }
@@ -293,8 +310,15 @@
 
   fill (0.0, r, c, r + a_nr - 1, c + a_nc - 1);
 
-  for (int i = 0; i < a.length (); i++)
-    elem (r+i, c+i) = a.elem (i, i);
+  int a_len = a.length ();
+
+  if (a_len > 0)
+    {
+      make_unique ();
+
+      for (int i = 0; i < a_len; i++)
+	xelem (r+i, c+i) = a.elem (i, i);
+    }
 
   return *this;
 }
@@ -326,14 +350,20 @@
 ComplexMatrix::insert (const ComplexColumnVector& a, int r, int c)
 {
   int a_len = a.length ();
+
   if (r < 0 || r + a_len > rows () || c < 0 || c >= cols ())
     {
       (*current_liboctave_error_handler) ("range error for insert");
       return *this;
     }
 
-  for (int i = 0; i < a_len; i++)
-    elem (r+i, c) = a.elem (i);
+  if (a_len > 0)
+    {
+      make_unique ();
+
+      for (int i = 0; i < a_len; i++)
+	xelem (r+i, c) = a.elem (i);
+    }
 
   return *this;
 }
@@ -352,8 +382,15 @@
 
   fill (0.0, r, c, r + a_nr - 1, c + a_nc - 1);
 
-  for (int i = 0; i < a.length (); i++)
-    elem (r+i, c+i) = a.elem (i, i);
+  int a_len = a.length ();
+
+  if (a_len > 0)
+    {
+      make_unique ();
+
+      for (int i = 0; i < a_len; i++)
+	xelem (r+i, c+i) = a.elem (i, i);
+    }
 
   return *this;
 }
@@ -363,10 +400,15 @@
 {
   int nr = rows ();
   int nc = cols ();
+
   if (nr > 0 && nc > 0)
-    for (int j = 0; j < nc; j++)
-      for (int i = 0; i < nr; i++)
-	elem (i, j) = val;
+    {
+      make_unique ();
+
+      for (int j = 0; j < nc; j++)
+	for (int i = 0; i < nr; i++)
+	  xelem (i, j) = val;
+    }
 
   return *this;
 }
@@ -376,10 +418,15 @@
 {
   int nr = rows ();
   int nc = cols ();
+
   if (nr > 0 && nc > 0)
-    for (int j = 0; j < nc; j++)
-      for (int i = 0; i < nr; i++)
-	elem (i, j) = val;
+    {
+      make_unique ();
+
+      for (int j = 0; j < nc; j++)
+	for (int i = 0; i < nr; i++)
+	  xelem (i, j) = val;
+    }
 
   return *this;
 }
@@ -389,6 +436,7 @@
 {
   int nr = rows ();
   int nc = cols ();
+
   if (r1 < 0 || r2 < 0 || c1 < 0 || c2 < 0
       || r1 >= nr || r2 >= nr || c1 >= nc || c2 >= nc)
     {
@@ -399,9 +447,14 @@
   if (r1 > r2) { int tmp = r1; r1 = r2; r2 = tmp; }
   if (c1 > c2) { int tmp = c1; c1 = c2; c2 = tmp; }
 
-  for (int j = c1; j <= c2; j++)
-    for (int i = r1; i <= r2; i++)
-      elem (i, j) = val;
+  if (r2 >= r1 && c2 >= c1)
+    {
+      make_unique ();
+
+      for (int j = c1; j <= c2; j++)
+	for (int i = r1; i <= r2; i++)
+	  xelem (i, j) = val;
+    }
 
   return *this;
 }
@@ -411,6 +464,7 @@
 {
   int nr = rows ();
   int nc = cols ();
+
   if (r1 < 0 || r2 < 0 || c1 < 0 || c2 < 0
       || r1 >= nr || r2 >= nr || c1 >= nc || c2 >= nc)
     {
@@ -421,9 +475,14 @@
   if (r1 > r2) { int tmp = r1; r1 = r2; r2 = tmp; }
   if (c1 > c2) { int tmp = c1; c1 = c2; c2 = tmp; }
 
-  for (int j = c1; j <= c2; j++)
-    for (int i = r1; i <= r2; i++)
-      elem (i, j) = val;
+  if (r2 >= r1 && c2 >=c1)
+    {
+      make_unique ();
+
+      for (int j = c1; j <= c2; j++)
+	for (int i = r1; i <= r2; i++)
+	  xelem (i, j) = val;
+    }
 
   return *this;
 }
@@ -766,7 +825,19 @@
 
   for (int j = 0; j < new_c; j++)
     for (int i = 0; i < new_r; i++)
-      result.elem (i, j) = elem (r1+i, c1+j);
+      result.xelem (i, j) = elem (r1+i, c1+j);
+
+  return result;
+}
+
+ComplexMatrix
+ComplexMatrix::extract_n (int r1, int c1, int nr, int nc) const
+{
+  ComplexMatrix result (nr, nc);
+
+  for (int j = 0; j < nc; j++)
+    for (int i = 0; i < nr; i++)
+      result.xelem (i, j) = elem (r1+i, c1+j);
 
   return result;
 }
@@ -785,7 +856,7 @@
 
   ComplexRowVector retval (nc);
   for (int j = 0; j < cols (); j++)
-    retval.elem (j) = elem (i, j);
+    retval.xelem (j) = elem (i, j);
 
   return retval;
 }
@@ -823,7 +894,7 @@
 
   ComplexColumnVector retval (nr);
   for (int j = 0; j < nr; j++)
-    retval.elem (j) = elem (j, i);
+    retval.xelem (j) = elem (j, i);
 
   return retval;
 }
diff -r 0a056052bc90 -r 236c10efcde2 liboctave/CMatrix.h
--- a/liboctave/CMatrix.h	Mon Feb 03 17:34:24 2003 +0000
+++ b/liboctave/CMatrix.h	Mon Feb 10 21:57:15 2003 +0000
@@ -128,6 +128,8 @@
 
   ComplexMatrix extract (int r1, int c1, int r2, int c2) const;
 
+  ComplexMatrix extract_n (int r1, int c1, int nr, int nc) const;
+
   // extract row or column i.
 
   ComplexRowVector row (int i) const;
diff -r 0a056052bc90 -r 236c10efcde2 liboctave/CRowVector.cc
--- a/liboctave/CRowVector.cc	Mon Feb 03 17:34:24 2003 +0000
+++ b/liboctave/CRowVector.cc	Mon Feb 10 21:57:15 2003 +0000
@@ -78,14 +78,20 @@
 ComplexRowVector::insert (const RowVector& a, int c)
 {
   int a_len = a.length ();
+
   if (c < 0 || c + a_len > length ())
     {
       (*current_liboctave_error_handler) ("range error for insert");
       return *this;
     }
 
-  for (int i = 0; i < a_len; i++)
-    elem (c+i) = a.elem (i);
+  if (a_len > 0)
+    {
+      make_unique ();
+
+      for (int i = 0; i < a_len; i++)
+	xelem (c+i) = a.elem (i);
+    }
 
   return *this;
 }
@@ -94,14 +100,20 @@
 ComplexRowVector::insert (const ComplexRowVector& a, int c)
 {
   int a_len = a.length ();
+
   if (c < 0 || c + a_len > length ())
     {
       (*current_liboctave_error_handler) ("range error for insert");
       return *this;
     }
 
-  for (int i = 0; i < a_len; i++)
-    elem (c+i) = a.elem (i);
+  if (a_len > 0)
+    {
+      make_unique ();
+
+      for (int i = 0; i < a_len; i++)
+	xelem (c+i) = a.elem (i);
+    }
 
   return *this;
 }
@@ -110,9 +122,15 @@
 ComplexRowVector::fill (double val)
 {
   int len = length ();
+
   if (len > 0)
-    for (int i = 0; i < len; i++)
-      elem (i) = val;
+    {
+      make_unique ();
+
+      for (int i = 0; i < len; i++)
+	xelem (i) = val;
+    }
+
   return *this;
 }
 
@@ -120,9 +138,15 @@
 ComplexRowVector::fill (const Complex& val)
 {
   int len = length ();
+
   if (len > 0)
-    for (int i = 0; i < len; i++)
-      elem (i) = val;
+    {
+      make_unique ();
+
+      for (int i = 0; i < len; i++)
+	xelem (i) = val;
+    }
+
   return *this;
 }
 
@@ -130,6 +154,7 @@
 ComplexRowVector::fill (double val, int c1, int c2)
 {
   int len = length ();
+
   if (c1 < 0 || c2 < 0 || c1 >= len || c2 >= len)
     {
       (*current_liboctave_error_handler) ("range error for fill");
@@ -138,8 +163,13 @@
 
   if (c1 > c2) { int tmp = c1; c1 = c2; c2 = tmp; }
 
-  for (int i = c1; i <= c2; i++)
-    elem (i) = val;
+  if (c2 >= c1)
+    {
+      make_unique ();
+
+      for (int i = c1; i <= c2; i++)
+	xelem (i) = val;
+    }
 
   return *this;
 }
@@ -148,6 +178,7 @@
 ComplexRowVector::fill (const Complex& val, int c1, int c2)
 {
   int len = length ();
+
   if (c1 < 0 || c2 < 0 || c1 >= len || c2 >= len)
     {
       (*current_liboctave_error_handler) ("range error for fill");
@@ -156,8 +187,13 @@
 
   if (c1 > c2) { int tmp = c1; c1 = c2; c2 = tmp; }
 
-  for (int i = c1; i <= c2; i++)
-    elem (i) = val;
+  if (c2 >= c1)
+    {
+      make_unique ();
+
+      for (int i = c1; i <= c2; i++)
+	xelem (i) = val;
+    }
 
   return *this;
 }
@@ -224,6 +260,17 @@
   return result;
 }
 
+ComplexRowVector
+ComplexRowVector::extract_n (int r1, int n) const
+{
+  ComplexRowVector result (n);
+
+  for (int i = 0; i < n; i++)
+    result.elem (i) = elem (r1+i);
+
+  return result;
+}
+
 // row vector by row vector -> row vector operations
 
 ComplexRowVector&
diff -r 0a056052bc90 -r 236c10efcde2 liboctave/CRowVector.h
--- a/liboctave/CRowVector.h	Mon Feb 03 17:34:24 2003 +0000
+++ b/liboctave/CRowVector.h	Mon Feb 10 21:57:15 2003 +0000
@@ -81,6 +81,8 @@
 
   ComplexRowVector extract (int c1, int c2) const;
 
+  ComplexRowVector extract_n (int c1, int n) const;
+
   // row vector by row vector -> row vector operations
 
   ComplexRowVector& operator += (const RowVector& a);
diff -r 0a056052bc90 -r 236c10efcde2 liboctave/ChangeLog
--- a/liboctave/ChangeLog	Mon Feb 03 17:34:24 2003 +0000
+++ b/liboctave/ChangeLog	Mon Feb 10 21:57:15 2003 +0000
@@ -1,3 +1,23 @@
+2003-02-10  John W. Eaton  <jwe@bevo.che.wisc.edu>
+
+	* CColVector.cc (ComplexColumnVector::extract_n): New function.
+	* CRowVector.cc (ComplexRowVector::extract_n): Likewise.
+	* CMatrix.cc (ComplexMatrix::extract_n): Likewise.
+	* dColVector.cc (ColumnVector::extract_n): Likewise.
+	* dRowVector.cc (RowVector::extract_n): Likewise.
+	* dMatrix.cc (Matrix::extract_n): Likewise.
+
+	* CColVector.cc (ComplexColumnVector::insert): Improve efficiency
+	with make_unique and xelem.
+	* CRowVector.cc (ComplexRowVector::insert): Likewise.
+	* CMatrix.cc (ComplexMatrix::insert, ComplexMatrix::fill,
+	ComplexMatrix::extract, ComplexMatrix::row,
+	ComplexMatrix::column): Likewise.
+	* dColVector.cc (ColumnVector::insert): Likewise.
+	* dRowVector.cc (RowVector::insert): Likewise.
+	* dMatrix.cc (Matrix::insert, Matrix::fill, Matrix::extract,
+	Matrix::row, Matrix::column): Likewise.
+
 2003-01-30  John W. Eaton  <jwe@bevo.che.wisc.edu>
 
 	* lo-mappers.cc (imag (double)): Return 0.0 for all args, even NaN.
diff -r 0a056052bc90 -r 236c10efcde2 liboctave/dColVector.cc
--- a/liboctave/dColVector.cc	Mon Feb 03 17:34:24 2003 +0000
+++ b/liboctave/dColVector.cc	Mon Feb 10 21:57:15 2003 +0000
@@ -69,14 +69,20 @@
 ColumnVector::insert (const ColumnVector& a, int r)
 {
   int a_len = a.length ();
+
   if (r < 0 || r + a_len > length ())
     {
       (*current_liboctave_error_handler) ("range error for insert");
       return *this;
     }
 
-  for (int i = 0; i < a_len; i++)
-    elem (r+i) = a.elem (i);
+  if (a_len > 0)
+    {
+      make_unique ();
+
+      for (int i = 0; i < a_len; i++)
+	xelem (r+i) = a.elem (i);
+    }
 
   return *this;
 }
@@ -85,9 +91,15 @@
 ColumnVector::fill (double val)
 {
   int len = length ();
+
   if (len > 0)
-    for (int i = 0; i < len; i++)
-      elem (i) = val;
+    {
+      make_unique ();
+
+      for (int i = 0; i < len; i++)
+	xelem (i) = val;
+    }
+
   return *this;
 }
 
@@ -95,6 +107,7 @@
 ColumnVector::fill (double val, int r1, int r2)
 {
   int len = length ();
+
   if (r1 < 0 || r2 < 0 || r1 >= len || r2 >= len)
     {
       (*current_liboctave_error_handler) ("range error for fill");
@@ -103,8 +116,13 @@
 
   if (r1 > r2) { int tmp = r1; r1 = r2; r2 = tmp; }
 
-  for (int i = r1; i <= r2; i++)
-    elem (i) = val;
+  if (r2 >= r1)
+    {
+      make_unique ();
+
+      for (int i = r1; i <= r2; i++)
+	xelem (i) = val;
+    }
 
   return *this;
 }
@@ -158,7 +176,18 @@
   ColumnVector result (new_r);
 
   for (int i = 0; i < new_r; i++)
-    result.elem (i) = elem (r1+i);
+    result.xelem (i) = elem (r1+i);
+
+  return result;
+}
+
+ColumnVector
+ColumnVector::extract_n (int r1, int n) const
+{
+  ColumnVector result (n);
+
+  for (int i = 0; i < n; i++)
+    result.xelem (i) = elem (r1+i);
 
   return result;
 }
diff -r 0a056052bc90 -r 236c10efcde2 liboctave/dColVector.h
--- a/liboctave/dColVector.h	Mon Feb 03 17:34:24 2003 +0000
+++ b/liboctave/dColVector.h	Mon Feb 10 21:57:15 2003 +0000
@@ -73,6 +73,8 @@
 
   ColumnVector extract (int r1, int r2) const;
 
+  ColumnVector extract_n (int r1, int n) const;
+
   // matrix by column vector -> column vector operations
 
   friend ColumnVector operator * (const Matrix& a, const ColumnVector& b);
diff -r 0a056052bc90 -r 236c10efcde2 liboctave/dMatrix.cc
--- a/liboctave/dMatrix.cc	Mon Feb 03 17:34:24 2003 +0000
+++ b/liboctave/dMatrix.cc	Mon Feb 10 21:57:15 2003 +0000
@@ -199,14 +199,20 @@
 Matrix::insert (const RowVector& a, int r, int c)
 {
   int a_len = a.length ();
+
   if (r < 0 || r >= rows () || c < 0 || c + a_len > cols ())
     {
       (*current_liboctave_error_handler) ("range error for insert");
       return *this;
     }
 
-  for (int i = 0; i < a_len; i++)
-    elem (r, c+i) = a.elem (i);
+  if (a_len > 0)
+    {
+      make_unique ();
+
+      for (int i = 0; i < a_len; i++)
+	xelem (r, c+i) = a.elem (i);
+    }
 
   return *this;
 }
@@ -215,14 +221,20 @@
 Matrix::insert (const ColumnVector& a, int r, int c)
 {
   int a_len = a.length ();
+
   if (r < 0 || r + a_len > rows () || c < 0 || c >= cols ())
     {
       (*current_liboctave_error_handler) ("range error for insert");
       return *this;
     }
 
-  for (int i = 0; i < a_len; i++)
-    elem (r+i, c) = a.elem (i);
+  if (a_len > 0)
+    {
+      make_unique ();
+
+      for (int i = 0; i < a_len; i++)
+	xelem (r+i, c) = a.elem (i);
+    }
 
   return *this;
 }
@@ -241,8 +253,15 @@
 
   fill (0.0, r, c, r + a_nr - 1, c + a_nc - 1);
 
-  for (int i = 0; i < a.length (); i++)
-    elem (r+i, c+i) = a.elem (i, i);
+  int a_len = a.length ();
+
+  if (a_len > 0)
+    {
+      make_unique ();
+
+      for (int i = 0; i < a_len; i++)
+	xelem (r+i, c+i) = a.elem (i, i);
+    }
 
   return *this;
 }
@@ -252,10 +271,15 @@
 {
   int nr = rows ();
   int nc = cols ();
+
   if (nr > 0 && nc > 0)
-    for (int j = 0; j < nc; j++)
-      for (int i = 0; i < nr; i++)
-	elem (i, j) = val;
+    {
+      make_unique ();
+
+      for (int j = 0; j < nc; j++)
+	for (int i = 0; i < nr; i++)
+	  xelem (i, j) = val;
+    }
 
   return *this;
 }
@@ -265,6 +289,7 @@
 {
   int nr = rows ();
   int nc = cols ();
+
   if (r1 < 0 || r2 < 0 || c1 < 0 || c2 < 0
       || r1 >= nr || r2 >= nr || c1 >= nc || c2 >= nc)
     {
@@ -275,9 +300,14 @@
   if (r1 > r2) { int tmp = r1; r1 = r2; r2 = tmp; }
   if (c1 > c2) { int tmp = c1; c1 = c2; c2 = tmp; }
 
-  for (int j = c1; j <= c2; j++)
-    for (int i = r1; i <= r2; i++)
-      elem (i, j) = val;
+  if (r2 >= r1 && c2 >= c1)
+    {
+      make_unique ();
+
+      for (int j = c1; j <= c2; j++)
+	for (int i = r1; i <= r2; i++)
+	  xelem (i, j) = val;
+    }
 
   return *this;
 }
@@ -465,7 +495,19 @@
 
   for (int j = 0; j < new_c; j++)
     for (int i = 0; i < new_r; i++)
-      result.elem (i, j) = elem (r1+i, c1+j);
+      result.xelem (i, j) = elem (r1+i, c1+j);
+
+  return result;
+}
+
+Matrix
+Matrix::extract_n (int r1, int c1, int nr, int nc) const
+{
+  Matrix result (nr, nc);
+
+  for (int j = 0; j < nc; j++)
+    for (int i = 0; i < nr; i++)
+      result.xelem (i, j) = elem (r1+i, c1+j);
 
   return result;
 }
@@ -484,7 +526,7 @@
 
   RowVector retval (nc);
   for (int j = 0; j < nc; j++)
-    retval.elem (j) = elem (i, j);
+    retval.xelem (j) = elem (i, j);
 
   return retval;
 }
@@ -522,7 +564,7 @@
 
   ColumnVector retval (nr);
   for (int j = 0; j < nr; j++)
-    retval.elem (j) = elem (j, i);
+    retval.xelem (j) = elem (j, i);
 
   return retval;
 }
diff -r 0a056052bc90 -r 236c10efcde2 liboctave/dMatrix.h
--- a/liboctave/dMatrix.h	Mon Feb 03 17:34:24 2003 +0000
+++ b/liboctave/dMatrix.h	Mon Feb 10 21:57:15 2003 +0000
@@ -103,6 +103,8 @@
 
   Matrix extract (int r1, int c1, int r2, int c2) const;
 
+  Matrix extract_n (int r1, int c1, int nr, int nc) const;
+
   // extract row or column i.
 
   RowVector row (int i) const;
diff -r 0a056052bc90 -r 236c10efcde2 liboctave/dRowVector.cc
--- a/liboctave/dRowVector.cc	Mon Feb 03 17:34:24 2003 +0000
+++ b/liboctave/dRowVector.cc	Mon Feb 10 21:57:15 2003 +0000
@@ -72,14 +72,20 @@
 RowVector::insert (const RowVector& a, int c)
 {
   int a_len = a.length ();
+
   if (c < 0 || c + a_len > length ())
     {
       (*current_liboctave_error_handler) ("range error for insert");
       return *this;
     }
 
-  for (int i = 0; i < a_len; i++)
-    elem (c+i) = a.elem (i);
+  if (a_len > 0)
+    {
+      make_unique ();
+
+      for (int i = 0; i < a_len; i++)
+	xelem (c+i) = a.elem (i);
+    }
 
   return *this;
 }
@@ -88,9 +94,15 @@
 RowVector::fill (double val)
 {
   int len = length ();
+
   if (len > 0)
-    for (int i = 0; i < len; i++)
-      elem (i) = val;
+    {
+      make_unique ();
+
+      for (int i = 0; i < len; i++)
+	xelem (i) = val;
+    }
+
   return *this;
 }
 
@@ -98,6 +110,7 @@
 RowVector::fill (double val, int c1, int c2)
 {
   int len = length ();
+
   if (c1 < 0 || c2 < 0 || c1 >= len || c2 >= len)
     {
       (*current_liboctave_error_handler) ("range error for fill");
@@ -106,8 +119,13 @@
 
   if (c1 > c2) { int tmp = c1; c1 = c2; c2 = tmp; }
 
-  for (int i = c1; i <= c2; i++)
-    elem (i) = val;
+  if (c2 >= c1)
+    {
+      make_unique ();
+
+      for (int i = c1; i <= c2; i++)
+	xelem (i) = val;
+    }
 
   return *this;
 }
@@ -159,7 +177,18 @@
   RowVector result (new_c);
 
   for (int i = 0; i < new_c; i++)
-    result.elem (i) = elem (c1+i);
+    result.xelem (i) = elem (c1+i);
+
+  return result;
+}
+
+RowVector
+RowVector::extract_n (int r1, int n) const
+{
+  RowVector result (n);
+
+  for (int i = 0; i < n; i++)
+    result.xelem (i) = elem (r1+i);
 
   return result;
 }
diff -r 0a056052bc90 -r 236c10efcde2 liboctave/dRowVector.h
--- a/liboctave/dRowVector.h	Mon Feb 03 17:34:24 2003 +0000
+++ b/liboctave/dRowVector.h	Mon Feb 10 21:57:15 2003 +0000
@@ -73,6 +73,8 @@
 
   RowVector extract (int c1, int c2) const;
 
+  RowVector extract_n (int c1, int n) const;
+
   // row vector by matrix -> row vector
 
   friend RowVector operator * (const RowVector& a, const Matrix& b);