What is the correct NDArray behavior of printf?

[John W. Eaton]

On 22-Apr-2004, David Bateman <address@hidden> wrote:

| The behavior of Matlab for printf, kron etc, is to horizontally or
| vertically stack the 2-D cuts of the NDArray objects. Thus in matlab
| 
| a = [1, 2; 3, 4]; a(:,:,2) = [5, 6; 7, 8]; sprintf('%f %f\n', a)
| 
| is legal and give
| 
| ans =
| 
| 1.000000 3.000000
| 2.000000 4.000000
| 5.000000 7.000000
| 6.000000 8.000000
| 
| 
| However, printf etc in octave called with NDArray arguments gives an
| error (when trying to transpose the NDArray). 

I don't see a transpose error, I see

  octave:4> printf ("%f %f\n", a)
  error: invalid conversion of NDArray to Matrix

| What is the correct behavior for these functions called with NDArrays?
| Is the Matlab behavior of reducing these arrays to 2-D objects the way
| to go? 

I think it is equivalent to

  printf ("%f %f\n", a(:))

which gives the compatible result.  I think the following change
should be all that is needed for this particular case.  There are a
number of other things that will also need to be changed in
oct-stream.cc to handle N-d arrays.

jwe


src/ChangeLog:

2004-04-22  John W. Eaton  <address@hidden>

        * oct-stream.cc (printf_value_cache::curr_value): Now NDArray.
        (printf_value_cache::double_value): Extract N-d array, not Matrix.

 
Index: src/oct-stream.cc
===================================================================
RCS file: /usr/local/cvsroot/octave/src/oct-stream.cc,v
retrieving revision 1.100
diff -u -r1.100 oct-stream.cc
--- a/src/oct-stream.cc 23 Feb 2004 22:10:32 -0000      1.100
+++ b/src/oct-stream.cc 22 Apr 2004 15:59:59 -0000
@@ -2123,7 +2123,7 @@
   int n_vals;
   int n_elts;
   const double *data;
-  Matrix curr_val;
+  NDArray curr_val;
   state curr_state;
 
   // Must create value cache with values!
@@ -2151,7 +2151,7 @@
        {
          octave_value tmp_val = values (val_idx);
 
-         curr_val = tmp_val.matrix_value ();
+         curr_val = tmp_val.array_value ();
 
          if (! error_state)
            {