### Legendre Form of Incomplete Elliptic Integrals

Function: double gsl_sf_ellint_F (double phi, double k, gsl_mode_t mode)
Function: int gsl_sf_ellint_F_e (double phi, double k, gsl_mode_t mode, gsl_sf_result * result)
These routines compute the incomplete elliptic integral @math{F(\phi,k)} to the accuracy specified by the mode variable mode.

Function: double gsl_sf_ellint_E (double phi, double k, gsl_mode_t mode)
Function: int gsl_sf_ellint_E_e (double phi, double k, gsl_mode_t mode, gsl_sf_result * result)
These routines compute the incomplete elliptic integral @math{E(\phi,k)} to the accuracy specified by the mode variable mode.

Function: double gsl_sf_ellint_P (double phi, double k, double n, gsl_mode_t mode)
Function: int gsl_sf_ellint_P_e (double phi, double k, double n, gsl_mode_t mode, gsl_sf_result * result)
These routines compute the incomplete elliptic integral @math{P(\phi,k,n)} to the accuracy specified by the mode variable mode.

Function: double gsl_sf_ellint_D (double phi, double k, double n, gsl_mode_t mode)
Function: int gsl_sf_ellint_D_e (double phi, double k, double n, gsl_mode_t mode, gsl_sf_result * result)
These functions compute the incomplete elliptic integral @math{D(\phi,k,n)} which is defined through the Carlson form @math{RD(x,y,z)} by the following relation,