Hi,
here is my report for the project week 16. The temporal raster algebra is working (fixed a lot issues with the precedence, temporal arithmetic operators and the command strings) and I uploaded the new module t.rast.mapcalc to my repository. This module is able to calculate r.mapcalc functions for space time raster datasets. In this first version only the basic functions of r.mapcalc are supported. I will write the documentation and extend the supported list of functions in the next few days.
Greetings
Thomas
Link to project wiki page:http://grasswiki.osgeo.org/wiki/GRASS_GSoC_2013_Temporal_GIS_Algebra_for_raster_and_vector_data_in_GRASS
Link to project repository: https://code.google.com/p/grass-gis-temporal-algebra/