June 18, 2006: Version 1.0.1. Revised the compile-time options to make
the default behavior saner.
June 27, 2006: Version 1.1. This version adds a new 2nd-order
integrator and a new function evaluator. Both make the program less
memory-hungry, but they have their downsides too: the 2nd-order integrator
is less accurate than the original 4th-order one and the evaluator is
slower. The original program, which is still included in the distribution,
is best for both speed and accuracy if you have the memory to run it. See
here for details.
July 13, 2006: Version 1.1.1. Fixes a variable initialization bug in
cart.c and cart2.c. Thanks to T. Gross for pointing out the problem.
July 23, 2006: Version 1.1.2. Adds a compile-time option to main.c to
allow for a constant offset to the density to prevent negative densities
from begin generated by numerical errors in the FFTW library. Gastner and
Newman (2004) found such an offset to be necessary when the density was
close to zero in some areas of the map. Most users can safely accept the
default settings for this offset parameter. This version of the program
also incorporates a few minor corrections in the error reporting code in
main.c. No changes were made in this version to cart.c itself or to any of
its cousins, cart2.c, cartv.c, or cart2v.c.
August 17, 2006: Version 1.2. This version adds a new small program
interp that will perform bilinear interpolation on the output of the
main program. Also a format error in the example data file uspop.dat has
been corrected. No changes were made in this version to cart.c itself or
to any of its cousins, cart2.c, cartv.c, or cart2v.c.
August 24, 2006: Version 1.2.1. Minor code clean-up.
November 9, 2006: Version 1.2.2. Minor improvements to interp and some
tune-up in main.c.