pub unsafe extern "C" fn lbfgsb(
n: c_int,
m: c_int,
x: *mut f64,
l: *mut f64,
u: *mut f64,
nbd: *mut c_int,
Fmin: *mut f64,
fn_: optimfn,
gr: optimgr,
fail: *mut c_int,
ex: *mut c_void,
factr: f64,
pgtol: f64,
fncount: *mut c_int,
grcount: *mut c_int,
maxit: c_int,
msg: *mut c_char,
trace: c_int,
nREPORT: c_int,
)