SUNDIALS (SUite of Nonlinear and DIfferential/ALgebraic equation Solvers)

This post has moved to eklausmeier.goip.de/blog/2013/07-27-sundials-suite-of-nonlinear-and-differentialalgebraic-equation-solvers.

Lawrence Livermore National Laboratory provides a suite of software packages for the solution of ordinary differential equations. This suite is called SUNDIALS.

SUNDIALS consists of

1. CVODE: solves initial value problems for ordinary differential equation (ODE) systems; successor of GEAR, EPISODE, then LSODE
2. CVODES: solves ODE systems and includes sensitivity analysis capabilities (forward and adjoint); successor of LSODES
3. IDA: solves initial value problems for differential-algebraic equation (DAE) systems; successor of DASSL
4. IDAS: solves DAE systems and includes sensitivity analysis capabilities (forward and adjoint); successor of DASSL
5. KINSOL: solves nonlinear algebraic systems

These subroutines are all written in C and have separate Fortran interfaces. Its authors are
Carol Woodward, Alan Hindmarsh, and Radu Serban. Others have also contributed to these codes.

An overview can be found in this presentation.

Various questions can be asked and searched here: nabble.com.

For decades LSODE was used as a yardstick for the numerical solution of ODEs.

More on the history of LSODE can be found in an interview with Alan Hindmarsh.

HipHop Virtual Machine can run WordPress

This post has moved to eklausmeier.goip.de/blog/2013/07-24-hiphop-virtual-machine-can-run-wordpress.

HipHop Virtual Machine (dead link) says that HHVM can run WordPress.

A more technical description of the HHVM can be found in Speeding up PHP-based development with HipHop VM. One of the main targets was to be as fast as the previous PHP to C++ translater. This goal has been achieved, see graph:

Unfortunately this also shows that Facebook has bundled all their energy on improving the virtual machine, but failed to improve the PHP to C++ translator.

Addendum 09-Dec-2013: See HipHop for PHP in Wikipedia. Performance has improved again. There still seem to be some issues with WordPress unit-tests.

Addendum 20-Dec-2013: HHVM: We are the 98.5% (and the 16%).

Blend “Söhne und Weltmacht” and “Why Nations Fail”

This post has moved to eklausmeier.goip.de/blog/2013/07-19-blend-sohne-und-weltmacht-and-why-nations-fail.

Gunnar Heinsohn (German Wikipedia, English Wikipedia) wrote a book with title Söhne und Weltmacht — Terror im Aufstieg und Fall der Nationen in German.