_external.py 文件源码

def sym(self, nested_scope=None):
        """Return the corresponding symbolic expression."""
        op = self.children[0].name
        expr = self.children[1]
        dispatch = {
            'sin': sympy.sin,
            'cos': sympy.cos,
            'tan': sympy.tan,
            'asin': sympy.asin,
            'acos': sympy.acos,
            'atan': sympy.atan,
            'exp': sympy.exp,
            'ln': sympy.log,
            'sqrt': sympy.sqrt
        }
        if op in dispatch:
            arg = expr.sym(nested_scope)
            return dispatch[op](arg)
        else:
            raise NodeException("internal error: undefined external")