Author Archives: jamesmath

RECOMB 2015

I attended my first RECOMB over the last few days. It was an excellent conference. There were some discussion regarding the +/- of single track conferences vs multi-track conferences. Overall I prefer the single track format, like RECOMB. It’s good … Continue reading

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more on bad python

Python is very convenient because we don’t have to type each variable, but this can also lead to sloppy mistakes.  A common mistake occurs when two variables point to the same memory and operations on one variable also changes the … Continue reading

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SDP and max-cut

Semi-definite programming generalizes linear programming. One standard definition of SDP is the following: such that and . Here are all matrices and the operation corresponds to entry-wise multiplication. An equivalent formulation of SDP is such that . So we can … Continue reading

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China 2014

I traveled in China from 12/28/2014 to 1/6/2015. With Yvonne and my parents, we went on a barnstorming tour through Longman Grottoes, Xi’an, Fu Zhou, Beijing and Tianjin. Highlights include: the headless, defaced stone statues at Longman; the Terracotta warriors … Continue reading

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nips 2014

Posters Neural word embedding as implicit matrix factorization. word2vec is equivalent to SVD of the word-by-context matrix. The proposed algorithm using negative sampling is computationally more efficient than SVD. Some of the preprocessing, e.g. eliminating rare words, improves the results. … Continue reading

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Bad python

Python is useful for many things, but in trying to be simple it’s also terrible in several ways. typing. For numpy arrays, if we have an int array then adding a float to an element of the array will automatically … Continue reading

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amazing ideas

Talk is cheap, idea is valuable. There are so many talks at Berkeley and Simons in particular and most of them are forgotten within a few weeks. The best talks convey one fresh and engaging idea. It is such ideas … Continue reading

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