The best serial implementaeon available the last is

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Unformatted text preview: rs –  it could also refer to other consideraEons like problem size Ideally, parallel programs should be wriben to scale arbitrarily –  i.e., “That worked well on 8 processors, but now that we’re running on 16 it falls over!” isn’t very saEsfying •  in part to make it portable across architectures •  in part because that’s your route to beber performance over Eme in a world without clock speed improvements CSEP 524: Parallel ComputaEon Winter 2013: Chamberlain 41 “Sherman, set the WABAC machine for 1999, CSE 373 (Data Structures and Algorithms)...” Simplifying Assumption ! Constants are insignificant compared to the asymptotic behavior of the program! –  expressed as a function of the problem size! –  expressed using functions like: n, n2, log n, 2n, etc.! UW, Autumn 1999! CSE 373 – Data Structures and Algorithms! Brad Chamberlain! Getting some Intuition... ! 100! 80! 60! 40! 20! 0! 1! UW, Autumn 1999! 2! 3! 4! 5! 6! 7! CSE 373 – Data Structures and Algorithms! 8! Brad Chamberlain! Using the Computer... ! 1200 1000 2^n n^3 n^2 100n 4n n log n 800 600 400 200 0 1 UW, Autumn 1999! 2 3 4 5 6 7 8 9 10 CSE 373 – Data Structures and Algorithms! Brad Chamberlain! On A Larger Scale... ! 1.4E+30 1.2E+30 2^n n^3 n^2 100n 4n n log n 1E+30 8E+29 6E+29 4E+29 2E+29 UW, Autumn 1999! 10 0 80 60 40 20 0 0 CSE 373 – Data Structures and Algorithms! Brad Chamberlain! Ignoring 2n ! 1200000 1000000 n^3 n^2 100n 4n n log n 800000 600000 400000 200000 UW, Autumn 1999! 10 0 80 60 40 20 0 0 CSE 373 – Data Structures and Algorithms! Brad Chamberlain! Ignoring n3 ! 12000 10000 n^2 100n 4n n log n 8000 6000 4000 2000 UW, Autumn 1999! 10 0 80 60 40 20 0 0 CSE 373 – Data Structures and Algorithms! Brad Chamberlain! On Yet a Larger Scale ! 1200000 1000000 800000 n^2 100n 4n 600000 400000 200000 UW, Autumn 1999! 10 00 80 0 60 0 40 0 20 0 0 0 CSE 373 – Data Structures and Algorithms! Brad Chamberlain! Smallest Functions Only ! UW, Autumn 1999! 90 10 0 80 70 60 50 40 30 20 4n n log n 10 0 450 400 350 300 250 200 150 100 50 0 CSE 373 – Data Structures and Algorithms! Brad Chamberlain! The Moral ! Performance can be broken down into primary and secondary effects! –  primary effects: asymptotic growth pattern! –  secondary effects: constant factors, l...
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This document was uploaded on 04/04/2014.

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