Lect 18 Reliable Computation I

CS257 © John E Savage

3

Coded Computation

l**Goal:** Reliably compute function gk(**x**1, **x**2) = **y **where **x**1, **x**2 and **y** are of
length *k*.

l**Method:**

l**Encode** **x**1, **x**2. Compute Gn(E(**x**1),E(**x**2)) = E(**y**). **x**1, **x**2 and **y** are
encoded in the same code *C *(prevents cheating).

lResult
of computation is **z**, a noisy version of **y**.

l**Decode
z **to a codeword in *C*.

lThe
challenge is to choose codes to ensure that **z** can be decoded correctly in the presence of errors.