用来定义、优化和模拟数学表达式计算：Theano
Theano 是一个 Python 库，用来定义、优化和模拟数学表达式计算，用于高效的解决多维数组的计算问题。Theano的特点：紧密集成Numpy；高效的数据密集型GPU计算；高效的符号微分运算；高速和稳定的优化；动态生成c代码；广泛的单元测试和自我验证。自2007年以来，Theano已被广泛应用于科学运算。theano使得构建深度学习模型更加容易，可以快速实现多种模型。
Theano is a Python library that allows you to define, optimize, and evaluate mathematical expressions involving multi-dimensional arrays efficiently. Theano features:
1）tight integration with NumPy – Use numpy.ndarray in Theano-compiled functions.
2）transparent use of a GPU – Perform data-intensive calculations up to 140x faster than with CPU.(float32 only)
3）efficient symbolic differentiation – Theano does your derivatives for function with one or many inputs.
4）speed and stability optimizations – Get the right answer for log(1+x) even when x is really tiny.
5）dynamic C code generation – Evaluate expressions faster.
6） extensive unit-testing and self-verification – Detect and diagnose many types of mistake.
Theano has been powering large-scale computationally intensive scientific investigations since 2007. But it is also approachable enough to be used in the classroom (IFT6266 at the University of Montreal).