Nonlinear Equations
*******************

 -- NLEqn_options: (void)
 -- NLEqn_options: (const NLEqn_options &OPT)

 -- NLEqn_options&: operator = (const NLEqn_options &OPT)

 -- void: init (void)

 -- void: copy (const NLEqn_options &OPT)

 -- void: set_default_options (void)

 -- void: set_tolerance (double VAL)

 -- double: tolerance (void)

 -- NLEqn: (void)
 -- NLEqn: (const ColumnVector&, const NLFUNC)
 -- NLEqn: (const NLEqn &A)

 -- NLEqn&: operator = (const NLEqn &A)

 -- void: resize (int N)

 -- void: set_states (const ColumnVector &X)

 -- ColumnVector: states (void) const

 -- int: size (void) const

 -- ColumnVector: solve (void)
 -- ColumnVector: solve (const ColumnVector &X)

 -- ColumnVector: solve (int &INFO)
     deftypefnx ColumnVector solve (const ColumnVector &X, int &INFO)