Sample sites as structural equations x = f(u), u exogenous noise.
A distribution is read as a mechanism: noise draws u, push computes the
value from it, abduct goes back from a value to its noise. For an
invertible mechanism (location-scale, inverse CDF of a continuous law)
abduction is exact. For a discrete one, many u give the same value, and
abduct draws u from its posterior given the value — here under the
inverse-CDF convention x = F⁻¹(u), u ~ U(0,1), under which that posterior is
uniform on the value's CDF interval. Which convention a discrete site uses
changes counterfactual answers and cannot be told from data, so it is fixed
here and documented rather than guessed.
Parameters come from the distribution at the site, so replaying a site with its old u under new parents is the counterfactual value.
Sample sites as structural equations x = f(u), u exogenous noise. A distribution is read as a mechanism: `noise` draws u, `push` computes the value from it, `abduct` goes back from a value to its noise. For an invertible mechanism (location-scale, inverse CDF of a continuous law) abduction is exact. For a discrete one, many u give the same value, and `abduct` draws u from its posterior given the value — here under the inverse-CDF convention x = F⁻¹(u), u ~ U(0,1), under which that posterior is uniform on the value's CDF interval. Which convention a discrete site uses changes counterfactual answers and cannot be told from data, so it is fixed here and documented rather than guessed. Parameters come from the distribution at the site, so replaying a site with its old u under new parents is the counterfactual value.
(mechanism? d)Whether distribution d can be read as a mechanism.
Whether distribution `d` can be read as a mechanism.
(abduct d x)Noise that gives value x: exact when the mechanism is
invertible, a draw from the posterior over u otherwise.
Noise that gives value `x`: exact when the mechanism is invertible, a draw from the posterior over u otherwise.
(noise d)A fresh draw of the site's exogenous noise.
A fresh draw of the site's exogenous noise.
(push d u)The value the mechanism gives noise u.
The value the mechanism gives noise `u`.
cljdoc builds & hosts documentation for Clojure/Script libraries
| Ctrl+k | Jump to recent docs |
| ← | Move to previous article |
| → | Move to next article |
| Ctrl+/ | Jump to the search field |