Mathematica “prelude”

Question

Is there any way to have the functions from a mathematica file be loaded on startup?

For example, in this excellent answer, Jens helps me out and gives me some functions for creating legends for plots. Instead of loading a file with those functions in it every time I load mathematica, can I instead put all the functions in a file and have them load every time I load mathematica?

Answer 1

There are several configuration files that you can use to load functionality at startup. They have the form

($BaseDirectory | $UserBaseDirectory)/(Kernel | FrontEnd)/init.m

where

$BaseDirectory 

is for every user on the system and

$UserBaseDirectory

is for you along and Kernel or FrontEnd specifies what you are configuring. In fact, a lot of the settings under the Preferences menu automatically write to $UserBaseDirectory/FrontEnd/init.m.

In your case, you are looking to add to $UserBaseDirctory/Kernel/init.m.

Answer 2

With $UserBaseDirectory/Kernel/init.m the most obvious place to put code which should be autoloaded has been mentioned.

But I think it might be worth mentioning that there is also the Autoload directory within $UserBaseDirectory where you can put any package file or package directory and those will automatically be loaded at startup. For the purpose mentioned I think that might be an even better place (after having the code set up as a proper package of course...).

I have not checked when the Autoload packages are loaded, but I know that init.m is loaded at a quite early stage, where I think some functionality that needs Java or the PacletManager might not yet be available. So that might also make a difference, depending on what the code actually does...