Month: March 2008

New insights into one-norm solvers from the Pareto curve

March 31, 2008 Documentation No comments

A new paper has been added to the collection of reproducible papers:

Geophysical inverse problems typically involve a trade off between data misfit and some prior. Pareto curves trace the optimal trade off between these two competing aims. These curves are commonly used in problems with two-norm priors where they are plotted on a log-log scale and are known as L-curves. For other priors, such as the sparsity-promoting one norm, Pareto curves remain relatively unexplored. We show how these curves lead to new insights into one-norm regularization. First, we confirm the theoretical properties of smoothness and convexity of these curves from a stylized and a geophysical example. Second, we exploit these crucial properties to approximate the Pareto curve for a large-scale problem. Third, we show how Pareto curves provide an objective criterion to gauge how different one-norm solvers advance towards the solution.

A journal requires tick labels on my plots to be oriented vertically and aligned on the left. How do I achieve that?

March 26, 2008 FAQ No comments

  • To place tick labels perpendicular to an axis (rather than parallel to it), use parallel#=n, where # is 1, 2, or 3.
  • .

  • To control the tick selection manually, use n#tic=, o#=num, and d#num=.
  • To control the label format, use format#= (the argument is a printf-style string)

The following example is provided in rsf/rsf/sfgraph:

Can I use Pylab figures in reproducible documents?

March 21, 2008 FAQ No comments

Now you can. See an example, where a figure originally generated with Matlab is replicated with Pylab.

To prepare your figures, follow the rules similar to those for Matlab and Mathematica figures:

  1. Create a directory called Pylab.
  2. Put figure-generating python scripts in this directory.
  3. Each script should have a .py suffix
  4. Each script should end with a command like

(the name junk_py.eps is important.)

3-D plane waves

March 14, 2008 Documentation No comments

Another old paper has been added to the collection of reproducible papers:

2008 Implementation Workshop

March 14, 2008 Celebration No comments

We are already well into 2008 — and could this year pass without a Madagascar Event?
Of course not!
A coding sprint is coming at full speed, towards us!
Madagascar developers are invited to congregate during May 23-27 in beautiful Golden, Colorado, for the

Yes, this is right. Instead of dozing in a dark room listening to others talk, we will actually write code together! We will give Madagascar a real push towards maturity. All necessary info, and more, can be found on the wiki page of the event. See you in Golden!