# Posts about numpy

## 2018-06-13 generating an unique seed for a given filename

When creating large simulations, you may sometimes create unique identifiers for each of it. This is useful to cache intermediate results for instance. This is the main function of hashes. We will here create a simple one-liner function to generate one.

## 2017-10-06 Improving calls to the LogGabor library

To code image as edges, for instance in the SparseEdges sparse coding scheme, we use a model of edges in images. A good model for these edges are bidimensional Log Gabor filter. This is implemented for instance in the LogGabor library. The library was designed to be precise, but not particularly for efficiency. In order to improve its speed, we demonstrate here the use of a cache to avoid redundant computations.

## 2017-09-20 The fastest 2D convolution in the world

Convolutions are essential components of any neural networks, image processing, computer vision ... but these are also a bottleneck in terms of computations... I will here benchmark different solutions using numpy, scipy or tensorflow. This is work-in-progress, so that any suggestion is welcome (for instance on StackExchange!

Sometimes, you need to pick up the $N$-th extremal values in a mutli-dimensional matrix.