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Question about systolic array algorithm #58

Closed sgmath12 closed 5 years ago

sgmath12 commented 5 years ago

In line 12, I think A' should be like this:

A' = [(i,j) -> ((j = 0) ? *w(i,j)I'(i,j)*, A(i,j-1)) + (W(i,j)I'(i,j)))]

But in lecture note,

A' = [(i,j) -> ((j = 0) ? 0, A(i,j-1)) + (W(i,j)*I'(i,j)))].

But if we set 0, then it is weird because the values of first column of A will be always 0, then

A(i,j-1)) = 0 when j = 1.

Am I right?

thanks.

yongsubaek commented 5 years ago

A' = [(i,j) -> ((j = 0) ? w(i,j)I'(i,j), A(i,j-1)) + (W(i,j)I'(i,j)))] should be A' = [(i,j) -> ((j = 0) ? w(i,j)I'(i,j), ( A(i,j-1) + (W(i,j)I'(i,j)))]

and

A' = [(i,j) -> ((j = 0) ? 0, A(i,j-1)) + (W(i,j)I'(i,j)))] should be A' = [(i,j) -> ((j = 0) ? 0, A(i,j-1)) + (W(i,j)I'(i,j))]

(Note that "(" and ")" are the only difference)

Then both mean if j = 0 A'(i,j) = W(i,j)I'(i,j) else A'(i,j) = A(i,j-1) + W(i,j)I'(i,j)

I think there are some typo

CauchyComplete commented 5 years ago

Professor discussed it in the class. Just removing the rightmost ')' will do. Note that the parentheses do not match, i.e. there is one extra ')'.

sgmath12 commented 5 years ago

Thank you.