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Equation 8 · Part 1 · Probing, Sparse Autoencoders, Patching, and Steering: The Main Interpretability Methods, Compared

Symbol f

f(x)f(x)
ff

What this part means

f is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

Its job in the formula

f is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

The passage around this formula

The formal objective has evolved since the earliest versions, and the direction of that evolution is itself informative. A dictionary decoder reconstructs the activation x from a sparse code f(x) :

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Learn the underlying idea

A function assigns an output to each allowed input. The expression f(x) means “apply f to x”.

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Sources cited in the article section

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