From bug-octave-request at bevo dot che dot wisc dot edu Wed Dec 10 10:11:34 2003
Subject: Incorrect dimensions of subarrays of ND Arrays
From: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
To: Quentin Spencer <qspencer at ieee dot org>
cc: bug-octave at bevo dot che dot wisc dot edu
Date: Wed, 10 Dec 2003 10:11:32 -0600

On  9-Dec-2003, I wrote:

| Please try the following patch.
| 
| Thanks,
| 
| jwe
| 
| liboctave/ChangeLog:
| 
| 2003-12-09  John W. Eaton  <jwe at bevo dot che dot wisc dot edu>
| 
| 	* dim-vector.h (dim_vector::chop_trailing_singleton_dims,
| 	dim_vector::dim_vector_rep::chop_trailing_singleton_dims):
| 	New functions.
| 	* Array.cc (ArrayN<T>::indexN): Use it.
| 	(ArrayN<T>::index (Array<idx_vector>&, int, const T&)): Likewise.

Unfortunately, this caused some other trouble.  An improved version is
appended below.  It should be used instead of the previous patch, not
in addition to it.

jwe


liboctave/ChangeLog:

2003-12-10  John W. Eaton  <jwe at bevo dot che dot wisc dot edu>

	* Array-util.cc (get_zero_len_size): Delete.
	* Array.cc (Array<T>::index (Array<idx_vector>&, int, const T&)):
	Handle zero-length result dimensions the same as empty original
	indices.

2003-12-09  John W. Eaton  <jwe at bevo dot che dot wisc dot edu>

	* dim-vector.h (dim_vector::chop_trailing_singleton_dims,
	dim_vector::dim_vector_rep::chop_trailing_singleton_dims):
	New functions.
	* Array.cc (ArrayN<T>::indexN): Use it.
	(ArrayN<T>::index (Array<idx_vector>&, int, const T&)): Likewise.


Index: liboctave/dim-vector.h
===================================================================
RCS file: /usr/local/cvsroot/octave/liboctave/dim-vector.h,v
retrieving revision 1.9
diff -u -r1.9 dim-vector.h
--- liboctave/dim-vector.h	24 Nov 2003 21:24:37 -0000	1.9
+++ liboctave/dim-vector.h	10 Dec 2003 16:09:21 -0000
 at @ -111,6 +111,17 @@
       return dims[i];
     }
 
+    void chop_trailing_singletons (void)
+    {
+      for (int i = ndims - 1; i > 1; i--)
+	{
+	  if (dims[i] == 1)
+	    ndims--;
+	  else
+	    break;
+	}
+    }
+
   private:
 
     // No assignment!
 at @ -200,7 +211,6 @@
       }
   }
 
-
   std::string str (char sep = 'x') const
   {
     OSSTREAM buf;
 at @ -287,6 +297,12 @@
 
     return retval;
   }
+
+  void chop_trailing_singletons (void)
+  {
+    make_unique ();
+    rep->chop_trailing_singletons ();
+  }
 };
 
 static inline bool
Index: liboctave/Array.cc
===================================================================
RCS file: /usr/local/cvsroot/octave/liboctave/Array.cc,v
retrieving revision 1.78
diff -u -r1.78 Array.cc
--- liboctave/Array.cc	25 Nov 2003 05:41:35 -0000	1.78
+++ liboctave/Array.cc	10 Dec 2003 16:09:19 -0000
 at @ -1859,6 +1859,7 @@
 	  else
 	    {
 	      dim_vector new_dims;
+
 	      new_dims.resize (n_dims);
 
 	      for (int i = 0; i < n_dims; i++)
 at @ -1867,6 +1868,8 @@
 		    new_dims(i) = 1;
 		}
 
+	      new_dims.chop_trailing_singletons ();
+
 	      retval = Array<T> (new_dims);
 	    }
 	}
 at @ -1885,6 +1888,8 @@
 		    new_dims(i) = 1;
 	        }
 
+	      new_dims.chop_trailing_singletons ();
+
 	      retval = Array<T> (tmp, new_dims);
 	    }
 	  else
 at @ -1917,6 +1922,8 @@
 	      result_dims(1) = (ntot > 0 ? 1 : 0);
 	    }
 
+	  result_dims.chop_trailing_singletons ();
+
 	  retval.resize (result_dims);
 
 	  int n = number_of_elements (result_dims);
 at @ -2022,14 +2029,12 @@
     {
       if (all_ok (ra_idx))
 	{
-	  if (any_orig_empty (ra_idx))
+	  if (any_orig_empty (ra_idx) || any_zero_len (frozen_lengths))
 	    {
+	      frozen_lengths.chop_trailing_singletons ();
+
 	      retval.resize (frozen_lengths);
 	    }
-	  else if (any_zero_len (frozen_lengths))
-	    {
-	      retval.resize (get_zero_len_size (frozen_lengths, dimensions));
-	    }
 	  else if (all_colon_equiv (ra_idx, dimensions) 
 		    && frozen_lengths.length () == n_dims)
 	    {
 at @ -2037,9 +2042,13 @@
 	    }
 	  else
 	    {
-	      retval.resize (frozen_lengths);
+	      dim_vector frozen_lengths_for_resize = frozen_lengths;
+
+	      frozen_lengths_for_resize.chop_trailing_singletons ();
 
-	      int n = number_of_elements (frozen_lengths);
+	      retval.resize (frozen_lengths_for_resize);
+
+	      int n = retval.length ();
 
 	      Array<int> result_idx (ra_idx.length (), 0);
 
 at @ -2051,17 +2060,13 @@
 		{
 		  elt_idx = get_elt_idx (ra_idx, result_idx); 
 	
-		  int numelem_result = 
-		    get_scalar_idx (result_idx, frozen_lengths);
-
 		  int numelem_elt = get_scalar_idx (elt_idx, this_dims);
 
-		  if (numelem_result > length () || numelem_result < 0 
-		      || numelem_elt > length () || numelem_elt < 0)
+		  if (numelem_elt > length () || numelem_elt < 0)
 		    (*current_liboctave_error_handler)
-		      ("attempt to grow array along ambiguous dimension");
+		      ("invalid N-d array index");
 		  else
-		    retval.checkelem (numelem_result) = checkelem (numelem_elt);
+		    retval.elem (i) = elem (numelem_elt);
 		
 		  increment_index (result_idx, frozen_lengths);
 	



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