no_opt function RV.F (df1 > 0, df2 > 0) = gsl_ran_fdist (get_rng (), df1, df2);
function NCDF.F (x >= 0, df1 > 0, df2 > 0, lambda >= 0) = unimplemented;
function NPDF.F (x >= 0, df1 > 0, df2 > 0, lmabda >= 0) = unimplemented;
no_opt function RV.F (df1 > 0, df2 > 0) = gsl_ran_fdist (get_rng (), df1, df2);
function NCDF.F (x >= 0, df1 > 0, df2 > 0, lambda >= 0) = unimplemented;
function NPDF.F (x >= 0, df1 > 0, df2 > 0, lmabda >= 0) = unimplemented;