Function SCIPcolGetFarkasCoef 

pub unsafe extern "C" fn SCIPcolGetFarkasCoef(
    col: *mut SCIP_COL,
    stat: *mut SCIP_STAT,
    lp: *mut SCIP_LP,
) -> f64

gets the Farkas coefficient y^T A_i of a column i in last LP (which must be infeasible)