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T(n,p)=α L(p)+β W(n,p)+γ C(n,p)T(n,p) = \alpha\,L(p) + \beta\,W(n,p) + \gamma\,C(n,p)

Why this formula appears here

The classical accounting for a collective operation separates three terms: a per-message latency, a per-byte transfer cost, and a per-byte computation cost for reductions [ 2 ] . Writing α\alpha for latency per message, β\beta for transfer time per byte and γ\gamma for reduction time per byte, the cost of a collective over p participants on n bytes takes the shape T(n,p)=α L(p)+β W(n,p)+γ C(n,p)T(n,p) = \alpha\,L(p) + \beta\,W(n,p) + \gamma\,C(n,p). where L counts message steps, W counts bytes crossing each link and C counts arithmetic. The whole art of collective algorithm design is choosing which of these terms to pay.

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Published contexts (1)

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T(n,p)=α L(p)+β W(n,p)+γ C(n,p),T(n,p) = \alpha\,L(p) + \beta\,W(n,p) + \gamma\,C(n,p),

Equation 9 · AI Hardware & Semiconductors

The Network Is the Computer Again

This equation states an equality: the expressions on both sides have the same value under the article’s assumptions.

The classical accounting for a collective operation separates three terms: a per-message latency, a per-byte transfer cost, and a per-byte computation cost for reductions [ 2 ] . Writing α\alpha for latency per message, β\beta for transfer time per byte and γ\gamma for reduction time per byte, the cost of a collective over p participants on n bytes takes the shape T(n,p)=α L(p)+β W(n,p)+γ C(n,p)T(n,p) = \alpha\,L(p) + \beta\,W(n,p) + \gamma\,C(n,p). where L counts message steps, W counts bytes crossing each link and C counts arithmetic. The whole art of collective algorithm design is choosing which of these terms to pay.

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