# Error estimation

Methods with time step adaptation require estimating the error of the solution. The error is then forwarded to algorithms from OrdinaryDiffEq.jl, see documentation.

`ManifoldDiffEq.calculate_eest`

— Method`calculate_eest(M::AbstractManifold, utilde, uprev, u, abstol, reltol, internalnorm, t)`

Estimate error of a solution of an ODE on manifold `M`

.

**Arguments**

`utilde`

– point on`M`

for error estimation,`uprev`

– point from before the current step,`u`

– point after the current step`,`abstol`

- abolute tolerance,`reltol`

- relative tolerance,`internalnorm`

– copied`internalnorm`

from the integrator,`t`

– time at which the error is estimated.

`ManifoldDiffEq.reltol_norm`

— Method`reltol_norm(M::AbstractManifold, u)`

Estimate the fraction `d_{min}/eps(number_eltype(u))`

where `d_{min}`

is the distance between `u`

, a point on `M`

, and the nearest distinct point on `M`

representable in the representation of `u`

.