struct PK_TOPOL_fcstr_param_d2p_s
       {
       PK_VECTOR_t  du2;
       PK_VECTOR_t dudv;
       PK_VECTOR_t  dv2;
       };
typedef struct PK_TOPOL_fcstr_param_d2p_s
               PK_TOPOL_fcstr_param_d2p_t;
struct PK_TOPOL_fctab_param_d2p_s
       {
       PK_TOPOL_fcstr_param_d2p_t *data;
       int                        length;
       };
typedef struct PK_TOPOL_fctab_param_d2p_s
               PK_TOPOL_fctab_param_d2p_t;


This is a support structure for PK_TOPOL_facet_r_t. It represents a three
column table of d2p/du2, d2p/dudv & d2p/dv2 second derivative surface values