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=. Extreme* Mountain Climbing. Optimization with Big Data. * in a billion dimensional space on a foggy day. Peter Richtarik School of Mathematics. BIG DATA. BIG Volume BIG Velocity BIG Variety. BIG Volume BIG Velocity BIG Variety.
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= Extreme* Mountain Climbing Optimization with Big Data * in a billion dimensional space on a foggy day Peter Richtarik School of Mathematics
BIG DATA BIG Volume BIG Velocity BIG Variety BIG Volume BIG Velocity BIG Variety • digital images & videos • transaction records • government records • health records • defence • internet activity (social media, wikipedia, ...) • scientific measurements (physics, climate models, ...) Sources
Arup (Truss Topology Design) Western General Hospital (Creutzfeldt-Jakob Disease) Ministry of Defence dstl lab (Algorithms for Data Simplicity) Royal Observatory (Optimal Planet Growth)
If you are not a God... x2 x3 x0 x1
Optimization as Lock Breaking A number representing the “quality” of a combination x =(x1, x2, x3, x4) F(x) = F(x1, x2, x3, x4) Setup: Combination maximizing F opens the lock Optimization Problem: Find combination maximizing F
How to Open a Lock with Billion Interconnected Dials? # variables/dials = n = 109 x1 x2 Assumption: F = F1 + F2 + ... + Fn ----------------------- Fjdepends on the neighbours of xjonly x4 xn x3 Example: F1 depends on x1,x2,x3 and x4 F2 depends on x1 andx2, ... F : RnR
Optimization Methods Computing Architectures Effectivity Efficiency Scalability Parallelism Distribution Asynchronicity Randomization • Multicore CPUs • GP GPU accelerators • Clusters / Clouds
Optimization Methods for Big Data • Randomized Coordinate Descent • P. R. and M. Takac: Parallel coordinate descent methods for big data optimization, ArXiv:1212.0873 [can solve a problem with 1 billion variables in 2 hours using 24 processors] • Stochastic (Sub) Gradient Descent • P. R. and M. Takac: Randomized lock-free methods for minimizing partially separable convex functions [can be applied to optimize an unknown function] • Both of the above M. Takac, A. Bijral, P. R. and N. Srebro: Mini-batch primal and dual methods for SVMs, ArXiv:1302.xxxx
Parallel Coordinate Descent holy grail settle for this start
TOOLS Probability HPC Matrix Theory Machine Learning