*Infpy* is a python package I have put together that implements some of 
the algorithms I (John Reid) have used in my research. In particular it 
has a Gaussian process package that is largely based on this excellent 
book__.

__ http://www.amazon.co.uk/Gaussian-Processes-Learning-Adaptive-Computation/dp/026218253X/

The infpy Gaussian process package features:

* Many different kernels are supported out of the box
* Kernel composition (point-wise sum and product)
* Maximum likelihood estimation of hyper-parameters
* Numpy integration
* Matplotlib plots
* Best of both worlds : ease of using an interpreted language but all 
  performance critical linear algebra performed in compiled code


