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Apr 19, 2014

nnForge v1.1.4

Here is new v1.1.4 release of nnForge. It contains mostly performance improvements but they are rather significant: the performance of convolutional layer in GPU (CUDA) backend improved from 1.15 TFLOPs to 2 TFLOPs for Galaxy Zoo example when running on NVIDIA GeForce GTX Titan, and the whole network performance improved from 1 TFLOPs to 1.55 TFLOPs. See the NSight VSE profiling screenshot:


2 TFLOPs on Titan running at 784 MHz... how efficient is it? Let's see: 2 TFLOPs / (784 Mhz * 14 SM * 192 fma/SM * 2 op/fma) = 47% of theoretical peak, which I consider a pretty good number. And there is certaily room for improvement here. Training could also benefit from these improvements; I plan to port these changes to hessian calculators and updaters soon.

Here are all the changes in this release:
  • C++11 limited support added: you can build everything except for CUDA backend - this is due to NVCC not yet supporting C++11
  • Improved testing and validating (feed forward) performance of convolutional layers in CUDA backend for Kepler at the same time greatly simplifying the code
  • Improved performance of max subsampling 2d tester for CUDA backend. The implementation is far from optimal yet