bridge/class-master/depend/pari/src/basemath/FpE.c
/* Computes the equation of the line tangent to R and returns its
   evaluation at the point Q. Also doubles the point R.
 */
Computes the equation of the line tangent to R and returns its
evaluation at the point Q. Also doubles the point R.
Computes the equation of the line tangent to R and returns its evaluation at the point Q . Also doubles the point R .
static GEN
FpXQE_tangent_update(GEN R, GEN Q, GEN a4, GEN T, GEN p, GEN *pt_R)
{
  if (ell_is_inf(R))
  {
    *pt_R = ellinf();
    return pol_1(get_FpX_var(T));
  }
  else if (!signe(gel(R,2)))
  {
    *pt_R = ellinf();
    return FpXQE_vert(R, Q, a4, T, p);
  } else {
    GEN slope;
    *pt_R = FpXQE_dbl_slope(R, a4, T, p, &slope);
    return FpXQE_Miller_line(R, Q, slope, a4, T, p);
  }
}
static GEN FpXQE_tangent_update ( GEN R , GEN Q , GEN a4 , GEN T , GEN p , GEN * pt_R ) { if ( ell_is_inf ( R ) ) { * pt_R = ellinf ( ) ; return pol_1 ( get_FpX_var ( T ) ) ; } else if ( ! signe ( gel ( R , 2 ) ) ) { * pt_R = ellinf ( ) ; return FpXQE_vert ( R , Q , a4 , T , p ) ; } else { GEN slope ; * pt_R = FpXQE_dbl_slope ( R , a4 , T , p , & slope ) ; return FpXQE_Miller_line ( R , Q , slope , a4 , T , p ) ; } }
Computes the equation of the line tangent to R and returns its
evaluation at the point Q.
Computes the equation of the line tangent to R and returns its evaluation at the point Q .