+
+/* Return the group # corresponding to the
+ independent variable with the value val
+*/
+static int
+get_group(const union value *val, struct variable *indep)
+{
+ int i;
+
+ for (i = 0; i < 2 ; ++i )
+ {
+ const int cmp = compare_values(val,&groups_values[i],indep->width) ;
+ switch ( criteria[i])
+ {
+ case CMP_EQ:
+ if ( 0 == cmp ) return i;
+ break;
+ case CMP_LT:
+ if ( 0 > cmp ) return i;
+ break;
+ case CMP_LE:
+ if ( cmp <= 0 ) return i;
+ break;
+ case CMP_GT:
+ if ( cmp > 0 ) return i;
+ break;
+ case CMP_GE:
+ if ( cmp >= 0 ) return i;
+ break;
+ default:
+ assert(0);
+ };
+ }
+
+ /* No groups matched */
+ return -1;
+}
+
+
+static void
+group_precalc (struct cmd_t_test *cmd )
+{
+ int i;
+ int j;
+
+ for(i=0; i< cmd->n_variables ; ++i)
+ {
+ struct t_test_proc *ttpr = &cmd->v_variables[i]->p.t_t;
+
+ /* There's always 2 groups for a T - TEST */
+ ttpr->n_groups = 2;
+ ttpr->gs = xmalloc(sizeof(struct group_statistics) * 2) ;
+
+ for (j=0 ; j < 2 ; ++j)
+ {
+ ttpr->gs[j].sum = 0;
+ ttpr->gs[j].n = 0;
+ ttpr->gs[j].ssq = 0;
+
+ if ( n_group_values == 2 )
+ ttpr->gs[j].id = groups_values[j];
+ else
+ ttpr->gs[j].id = groups_values[0];
+ ttpr->gs[j].criterion = criteria[j];
+ }
+ }
+
+}
+
+static int
+group_calc (const struct ccase *c, struct cmd_t_test *cmd)
+{
+ int i;
+ int g;
+
+ const union value *gv = &c->data[indep_var->fv];
+
+ const double weight = dict_get_case_weight(default_dict,c,&bad_weight_warn);
+
+ if ( value_is_missing(gv,indep_var) )
+ {
+ return 0;
+ }
+
+ if ( cmd->miss == TTS_LISTWISE )
+ {
+ for(i=0; i< cmd->n_variables ; ++i)
+ {
+ struct variable *v = cmd->v_variables[i];
+ const union value *val = &c->data[v->fv];
+
+ if (value_is_missing(val,v) )
+ {
+ return 0;
+ }
+ }
+ }
+
+
+ gv = &c->data[indep_var->fv];
+
+ g = get_group(gv,indep_var);
+
+
+ /* If the independent variable doesn't match either of the values
+ for this case then move on to the next case */
+ if (g == -1 )
+ return 0;
+
+ for(i=0; i< cmd->n_variables ; ++i)
+ {
+ struct variable *var = cmd->v_variables[i];
+
+ struct group_statistics *gs = &var->p.t_t.gs[g];
+
+ const union value *val=&c->data[var->fv];
+
+ if ( !value_is_missing(val,var) )
+ {
+ gs->n+=weight;
+ gs->sum+=weight * val->f;
+ gs->ssq+=weight * pow2(val->f);
+ }
+ }
+
+ return 0;
+}
+
+
+static void
+group_postcalc ( struct cmd_t_test *cmd )
+{
+ int i;
+ int j;
+
+ for(i=0; i< cmd->n_variables ; ++i)
+ {
+ for (j=0 ; j < 2 ; ++j)
+ {
+ struct group_statistics *gs;
+ gs=&cmd->v_variables[i]->p.t_t.gs[j];
+
+ gs->mean = gs->sum / gs->n;
+
+ gs->s_std_dev= sqrt(
+ ( (gs->ssq / gs->n ) - gs->mean * gs->mean )
+ ) ;
+
+ gs->std_dev= sqrt(
+ gs->n/(gs->n-1) *
+ ( (gs->ssq / gs->n ) - gs->mean * gs->mean )
+ ) ;
+
+ gs->se_mean = gs->std_dev / sqrt(gs->n);
+ }
+ }
+}
+
+
+
+static void
+calculate(const struct casefile *cf, void *cmd_)
+{
+ struct ssbox stat_summary_box;
+ struct trbox test_results_box;
+
+ struct casereader *r;
+ const struct ccase *c;
+
+ struct cmd_t_test *cmd = (struct cmd_t_test *) cmd_;
+
+ common_precalc(cmd);
+ for(r = casefile_get_reader (cf);
+ casereader_read (r, &c) ; )
+ {
+ common_calc(c,cmd);
+ }
+ casereader_destroy (r);
+ common_postcalc(cmd);
+
+ switch(mode)
+ {
+ case T_1_SAMPLE:
+ one_sample_precalc(cmd);
+ for(r = casefile_get_reader (cf);
+ casereader_read (r, &c) ; )
+ {
+ one_sample_calc(c,cmd);
+ }
+ casereader_destroy (r);
+ one_sample_postcalc(cmd);
+
+ break;
+ case T_PAIRED:
+ paired_precalc(cmd);
+ for(r = casefile_get_reader (cf);
+ casereader_read (r, &c) ; )
+ {
+ paired_calc(c,cmd);
+ }
+ casereader_destroy (r);
+ paired_postcalc(cmd);
+
+ break;
+ case T_IND_SAMPLES:
+
+ group_precalc(cmd);
+ for(r = casefile_get_reader (cf);
+ casereader_read (r, &c) ; )
+ {
+ group_calc(c,cmd);
+ }
+ casereader_destroy (r);
+ group_postcalc(cmd);
+
+
+ levene(cf, indep_var, cmd->n_variables, cmd->v_variables,
+ (cmd->miss == TTS_LISTWISE)?LEV_LISTWISE:LEV_ANALYSIS ,
+ value_is_missing);
+ break;
+ }
+
+ ssbox_create(&stat_summary_box,cmd,mode);
+ ssbox_populate(&stat_summary_box,cmd);
+ ssbox_finalize(&stat_summary_box);
+
+ if ( mode == T_PAIRED)
+ pscbox();
+
+ trbox_create(&test_results_box,cmd,mode);
+ trbox_populate(&test_results_box,cmd);
+ trbox_finalize(&test_results_box);
+
+}