Function SCIPfixParam 

pub unsafe extern "C" fn SCIPfixParam(
    scip: *mut SCIP,
    name: *const c_char,
) -> SCIP_RETCODE

fixes the value of an existing parameter

@return \ref SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See \ref SCIP_Retcode “SCIP_RETCODE” for a complete list of error codes.

@note: Be careful with this method! Some general settings, e.g., the time or node limit, should not be fixed because they have to be changed for sub-SCIPs.