Natural logarithm: x -> log(x)

::

 log(float x) -> float
 log(DM x) -> DM
 log(SX x) -> SX
 log(MX x) -> MX

Extra doc: https://github.com/casadi/casadi/wiki/L_pg

Doc source: https://github.com/casadi/casadi/blob/develop/casadi/core/generic_expression.hpp#L470

Implementation: https://github.com/casadi/casadi/blob/develop/casadi/core/generic_expression.hpp#L470-L472

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