From bug-octave-request at bevo dot che dot wisc dot edu  Fri Apr 27 13:23:31 2001
Subject: NaN-related bug in SORT
From: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
To: a dot schloegl at ieee dot org
Cc: bug-octave at bevo dot che dot wisc dot edu
Date: Fri, 27 Apr 2001 13:23:24 -0500

On 27-Apr-2001, Alois =?iso-8859-1?Q?Schl=F6gl?= <schloegl at dpmi dot tu-graz dot ac dot at> wrote:

| octave:6> sort([3,4,nan,3,4,nan])
| ans =
| 
|     3    4  NaN    3    4  NaN
| 
| Sorry, I've no patch. But I'd suggest that NaN's should be sorted at one
| end of the array. IEEE754/854 would suggest to but NaN above +Inf.

Please try the following patch.  FWIW, I think this is also compatible
with the way Matlab works.

Thanks,

jwe


2001-04-27  John W. Eaton  <jwe at bevo dot che dot wisc dot edu>

	* DLD-FUNCTIONS/sort.cc (mx_sort): Check for NaNs in comparisons.


Index: sort.cc
===================================================================
RCS file: /usr/local/cvsroot/octave/src/DLD-FUNCTIONS/sort.cc,v
retrieving revision 1.4
diff -c -r1.4 sort.cc
*** sort.cc	2000/01/12 03:07:52	1.4
--- sort.cc	2001/04/27 18:21:43
***************
*** 24,29 ****
--- 24,31 ----
  #include <config.h>
  #endif
  
+ #include "lo-mappers.h"
+ 
  #include "defun-dld.h"
  #include "error.h"
  #include "gripes.h"
***************
*** 175,181 ****
  	{
  	  Array<int> l = create_index_array (nr);
  
! 	  DO_SORT (nr, (m (p-1, j) > m (q-1, j)));
  
  	  MATRIX_CREATE_RETURN_VALUES (ms, m);
  	}
--- 177,183 ----
  	{
  	  Array<int> l = create_index_array (nr);
  
! 	  DO_SORT (nr, (xisnan (m (p-1, j)) || m (p-1, j) > m (q-1, j)));
  
  	  MATRIX_CREATE_RETURN_VALUES (ms, m);
  	}
***************
*** 208,214 ****
      {
        Array<int> l = create_index_array (n);
  
!       DO_SORT (n, (v (p-1) > v (q-1)));
  
        VECTOR_CREATE_RETURN_VALUES (vs, v);
      }
--- 210,216 ----
      {
        Array<int> l = create_index_array (n);
  
!       DO_SORT (n, (xisnan (v (p-1)) || v (p-1) > v (q-1)));
  
        VECTOR_CREATE_RETURN_VALUES (vs, v);
      }
***************
*** 243,258 ****
  	{
  	  Array<int> l = create_index_array (nr);
  
! 	  int all_elts_real = 1;
  	  for (int i = 0; i < nr; i++)
  	    if (imag (cm (i, j)) != 0.0)
  	      {
! 		all_elts_real = 0;
  		break;
  	      }
  
  	  DO_SORT (nr, ((all_elts_real
! 			 && real (cm (p-1, j)) > real (cm (q-1, j)))
  			|| abs (cm (p-1, j)) > abs (cm (q-1, j))));
  
  	  MATRIX_CREATE_RETURN_VALUES (cms, cm);
--- 245,262 ----
  	{
  	  Array<int> l = create_index_array (nr);
  
! 	  bool all_elts_real = true;
  	  for (int i = 0; i < nr; i++)
  	    if (imag (cm (i, j)) != 0.0)
  	      {
! 		all_elts_real = false;
  		break;
  	      }
  
  	  DO_SORT (nr, ((all_elts_real
! 			 && (xisnan (real (cm (p-1, j)))
! 			     || real (cm (p-1, j)) > real (cm (q-1, j))))
! 			|| xisnan (cm (p-1, j))
  			|| abs (cm (p-1, j)) > abs (cm (q-1, j))));
  
  	  MATRIX_CREATE_RETURN_VALUES (cms, cm);
***************
*** 286,301 ****
      {
        Array<int> l = create_index_array (n);
  
!       int all_elts_real = 1;
        for (int i = 0; i < n; i++)
  	if (imag (cv (i)) != 0.0)
  	  {
! 	    all_elts_real = 0;
  	    break;
  	  }
  
        DO_SORT (n, ((all_elts_real
! 		    && real (cv (p-1)) > real (cv (q-1)))
  		   || abs (cv (p-1)) > abs (cv (q-1))));
  
        VECTOR_CREATE_RETURN_VALUES (cvs, cv);
--- 290,307 ----
      {
        Array<int> l = create_index_array (n);
  
!       bool all_elts_real = true;
        for (int i = 0; i < n; i++)
  	if (imag (cv (i)) != 0.0)
  	  {
! 	    all_elts_real = false;
  	    break;
  	  }
  
        DO_SORT (n, ((all_elts_real
! 		    && (xisnan (real (cv (p-1)))
! 			|| real (cv (p-1)) > real (cv (q-1))))
! 		   || xisnan (cv (p-1))
  		   || abs (cv (p-1)) > abs (cv (q-1))));
  
        VECTOR_CREATE_RETURN_VALUES (cvs, cv);



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