4.8. - Four-Circle Files
Most questions regarding the behavior of spec when used with a four-circle diffractometer can ultimately be resolved by consulting the appropriate source code. The file geo_fourc.c in the standard distribution of spec contains the code for all the four-circle calculations. The file u_hook.c contains a few lines of code that connect the code in geo_fourc.c with the rest of the program. Finally, the files macros/fourc.src and macros/ub.mac in the standard distribution contains the definitions for all the four-circle and orientation matrix macros.