- # NLL is a symbolic variable ; to get the actual value of NLL, this symbolic
- # expression has to be compiled into a Theano function (see the Theano
- # tutorial for more details)
- NLL = -T.sum(T.log(p_y_given_x)[T.arange(y.shape[0]), y])
- # note on syntax: T.arange(y.shape[0]) is a vector of integers [0,1,2,...,len(y)].
- # Indexing a matrix M by the two vectors [0,1,...,K], [a,b,...,k] returns the
- # elements M[0,a], M[1,b], ..., M[K,k] as a vector. Here, we use this
- # syntax to retrieve the log-probability of the correct labels, y.
theano中的index好怪異。。比如最大似然估計的損失計算部分。
發表評論
所有評論
還沒有人評論,想成為第一個評論的人麼? 請在上方評論欄輸入並且點擊發布.