My newest project is a Python library for monitoring memory consumption
of arbitrary process, and one of its most useful features is the
line-by-line analysis of memory usage for Python code. I wrote a basic
prototype six months ago after being surprised by the lack of related
tools. I wanted …

A little experiment to see what low rank approximation looks like. These
are the best rank-k approximations (in the Frobenius norm) to the a
natural image for increasing values of k and an original image of rank
512.

Python code can be found here. GIF animation made
using ImageMagic's convert …

In scipy's development version there's a new function closely related to
the QR-decomposition of a matrix and to the least-squares solution of
a linear system. What this function does is to compute the
QR-decomposition of a matrix and then multiply the resulting orthogonal
factor by another arbitrary matrix. In pseudocode …

As a warm-up for the upcoming EuroScipy-conference, some of the
scikit-learn developers decided to gather and work together for a
couple of days. Today was the first day and there was only a handfull of
us, as the real kickoff is expected tomorrow. Some interesting coding
happened, although most of …

Ridge coefficients for multiple values of the regularization parameter
can be elegantly computed by updating the *thin* SVD decomposition of
the design matrix:

import numpy as np
from scipy import linalg
def ridge(A, b, alphas):
"""
Return coefficients for regularized least squares
min ||A x - b||^2 + alpha ||x||^2 …

**Update: a fast and stable norm was added to scipy.linalg in August
2011 and will be available in scipy 0.10** Last week I discussed with
Gael how we should compute the euclidean norm of a vector a using
SciPy. Two approaches suggest themselves, either calling
scipy.linalg.norm …

I was last weekend in FOSDEM presenting scikits.learn (here are
the slides I used at the Data Analytics Devroom). Kudos to Olivier
Grisel and all the people who organized such a fun and authentic
meeting!

I've been working lately with Alexandre Gramfort coding the LARS
algorithm in scikits.learn. This algorithm computes the solution to
several general linear models used in machine learning: LAR, Lasso,
Elasticnet and Forward Stagewise. Unlike the implementation by
coordinate descent, the LARS algorithm gives the full coefficient path
along the …

En la ciudad fabrican a las personas en serie. En el campo, los siguen
haciendo a mano: los moldean, los secan al sol y luego los pintan, por
eso son tan especiales. Primer concierto de la nueva gira en Mengíbar, y
uno de los fines de semana más intensos que …

Por fin encontré la manera para no dejarme la vista intentando
distinguir azul oscuro sobre negro. Se trata de añadir el código a tu
.bash_profile y los directorios se te colorearán de un verde mucho más
legible alias ls='ls --color'
LS_COLORS='di=1:fi=0:ln=31:pi=5 …