while (i < cov->dim)
{
struct string str;
int idx = i - cov->n_vars;
const struct interaction *iact =
categoricals_get_interaction_by_subscript (cov->categoricals, idx);
while (i < cov->dim)
{
struct string str;
int idx = i - cov->n_vars;
const struct interaction *iact =
categoricals_get_interaction_by_subscript (cov->categoricals, idx);