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courses:rg:2012:distributed-perceptron [2012/12/16 23:02] machacek |
courses:rg:2012:distributed-perceptron [2012/12/16 23:44] (current) machacek |
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* You can use any structured input x (not just vector, sentence for example) and any structured output y (not just binary value, parse tree for example) | * You can use any structured input x (not just vector, sentence for example) and any structured output y (not just binary value, parse tree for example) | ||
* You need to have fuction f(x,y) which returns feature representation of candidate input-output pair | * You need to have fuction f(x,y) which returns feature representation of candidate input-output pair | ||
- | * Using the Theorem 1, you can bound the number of mistakes made during the training | + | * Using the Theorem 1, you can bound the number of mistakes made during the training |
+ | * The computational time is therefore also bounded. | ||
+ | * This holds only for linearly separable sets. | ||
+ | * Other remarks and discussed issues | ||
+ | * The perceptron training algorithm does not always return the same weights (unlike maximal margin). It depends on order of training data. | ||
+ | * How the inference is done in the difficult tasks like parsing? Iterating all possible y? Approximation? | ||
==== 4 Distributed Structured Perceptron ==== | ==== 4 Distributed Structured Perceptron ==== | ||
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=== 4.1 Parameter Mixing === | === 4.1 Parameter Mixing === | ||
+ | |||
+ | * First attempt to map-reduce algorithm | ||
+ | * Divide the training data into shards | ||
+ | * In MAP step, train a perceptron on each shard | ||
+ | * In REDUCE step, average the trained weight vectors | ||
=== 4.2 Iterative Parameter Mixing === | === 4.2 Iterative Parameter Mixing === |