- tags
- Neural networks, Algorithm

Adaptive computation time (ACT) was introduced in (Graves 2017) as a way to make computations in RNN adaptive. The network learns how many computational steps to use before emitting an output.

This is done by outputting an extra *halting probability* at each update step, and considering two timelines:

- the input timeline which plays the role of an outer loop, at each of those step, a new input symbol is fed to the RNN. This step outputs a single output vector.
- the internal processing timeline, this is the inner loop being run at each of the input steps. This runs until the cumulative halting probability is above a threshold and emits as many output values as steps..

## Bibliography

Graves, Alex. February 2017. “Adaptive Computation Time for Recurrent Neural Networks”. *arXiv:1603.08983 [Cs]*, February.