Theano/Theano — pull request #934 by goodfeli (2012-09-17 23:46:53+00:00)
Title: Gpu max

Implements reduction by max operation on gpu.
Does this by replacing GpuSum with a new general GpuCAReduce op.
This requires replacing the local_gpu_sum optimization with a local_gpu_careduce optimization.
Not all combinations of reduction axes and reduction ops are supported. The new local_gpu_careduce optimization understands this and will not put ops with unsupported settings in the graph.
Adds a unit test, test_max, which is based on the pre-existing test_sum case. The new test runs on just those cases that the new CAReduce op supports.