stan-dev/stan — pull request #166 by bob-carpenter (2013-07-27 14:06:51+00:00)
Title: Feature/softmax unfold

Bunch of changes, all with tests:

* unfolded the derivatives for softmax
* added log_softmax
* vectorized categorical_log and optimized
* added categorical_logit
* added log_sum_exp for vector, row vector and matrix with unfolded derivatives
* added op_matrix_vari class to support log_sum_exp