mvpa2.misc.errorfx.relative_rms_error

mvpa2.misc.errorfx.relative_rms_error(predicted, target)

Ratio between RMSE and root mean power of target output.

So it can be considered as a scaled RMSE – perfect reconstruction has values near 0, while no reconstruction has values around 1.0. Word of caution – it is not commutative, ie exchange of predicted and target might lead to completely different answers