I copied the code that yields the diagram presented in this answer but all I get is the error message
! LaTeX Error: File `pst-calculate.sty' not found. Type X to quit or to proceed, or enter new name. (Default extension: sty) Enter file name: ! Emergency stop.
I have just updated all my packages. When I look up the name of the missing style file, I find pst-calculate.tpm in the directory
C:\Program Files\MiKTeX 2.9\tpm\packages\pst-calculate.tpm
Also, the missing file can be found here. Will my problem be solved if I just save it to the correct folder? If so, which is it? Let me know if I need to give you more information.
Following UlrikeFischer's advice I managed to install the package pst-calculate, and after some tweaks, it worked. Thanks to Ulrike for the help.