数值计算中的相对误差，绝对误差相对误差：Relativetolerance(RTOL)controlslocalerrorrelativetothesizeofthesolution—RTOL=10-4meansthaterrorsarecontrolledto0.01%绝对误差：Absolutetolerances(ATOL)controlerrorwhenasolutioncomponentmayb