Re: case_data_rw()

[Jason Stover]

On Fri, Apr 14, 2006 at 10:36:37AM -0700, Ben Pfaff wrote:
> > The LIST command shows nothing but missing values for the new
> > variable. And gdb doesn't follow the program in the casereading
> > loop, so it's hard to see what's going on. (But I can see
> > *lc->residual returns the correct doubles.)
> 
> I think there must be some other subtlety that is causing a
> problem.  Perhaps you can post the file diff or otherwise
> describe the larger context.

Here's the diff between my copy of regression.q the version currently in CVS.

508,509c508
<   int case_num;
<   double residual;
---
>   unsigned long case_num;
511a511,512
>   union value *w_val = NULL;
>   struct variable *residuals = NULL;
520a522
>       residuals = dict_create_var_assert (default_dict, "residuals", 0);
528c530,531
<             for (i = 0; i < n_variables; ++i)
---
>             i = 0;
>             while (i < n_variables)
533a537
>                     i = n_variables;
534a539
>                 i++;
536c541,543
<             residual = (*lc->residual) ((const struct variable **) 
v_variables, 
---
>             w_val = case_data_rw (&c, residuals->fv);
>             assert (w_val);
>             w_val->f = (*lc->residual) ((const struct variable **) 
> v_variables, 

Here is the syntax I ran:

     data list list / v0 to v2.
     begin data
      0.65377128  7.735648 -23.97588
      -0.13087553  6.142625 -19.63854
       0.34880368  7.651430 -25.26557
       0.69249021  6.125125 -16.57090
       -0.07368178  8.245789 -25.80001
       -0.34404919  6.031540 -17.56743
        0.75981559  9.832291 -28.35977
        -0.46958313  5.343832 -16.79548
        -0.06108490  8.838262 -29.25689
        0.56154863  6.200189 -18.58219
        end data
        regression /variables=v0 v1 v2 /statistics defaults /dependent=v2 
/method=enter /save=residuals.
        list.

And here is the listing (without the regression results):

      v0       v1       v2 residuals
-------- -------- -------- ---------
     .65     7.74   -23.98       .00 
    -.13     6.14   -19.64       .   
     .35     7.65   -25.27       .   
     .69     6.13   -16.57       .   
    -.07     8.25   -25.80       .   
    -.34     6.03   -17.57       .   
     .76     9.83   -28.36       .   
    -.47     5.34   -16.80       .   
    -.06     8.84   -29.26       .   
     .56     6.20   -18.58       .   

printf("%f\n",w_val->f) just after the assignment w_val->f = ... shows
the correct value in w_val, but after that it's lost.

It's hard to see what's happening in gdb because case_data_rw() and
case_num() are inline.  gdb doesn't follow the source well, and tells
me w_val isn't a symbol, etc. I #define'd DEBUGGING 1 in case.h, but
then dictionary.o would not link.  Is it necessary to have the functions
in case.c as inline, given the hassle it causes while debugging?

-Jason