Re: Begginer's question: Saving a function for later use

*To*: mathgroup at smc.vnet.net*Subject*: [mg128046] Re: Begginer's question: Saving a function for later use*From*: "djmpark" <djmpark at comcast.net>*Date*: Tue, 11 Sep 2012 02:33:29 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*Delivered-to*: l-mathgroup@wolfram.com*Delivered-to*: mathgroup-newout@smc.vnet.net*Delivered-to*: mathgroup-newsend@smc.vnet.net*References*: <19207797.49366.1347264435806.JavaMail.root@m06>

Pedro, Any definitions you make within a notebook are only active in the current session. If you quit Mathematica and then reopen your notebook you will have to reevaluate your definitions. There are several common and simple ways to handle this. 1) Make your definitions Initialization cells. You can do this on the context menu for a cell and selecting Initialization Cell. Then when you reopen the notebook and try to evaluate any cell Mathematica will ask if you want to evaluate all the Initialization cells first. 2) It is useful to learn how to use Sections, and also Text cells for commentary and description. Then you could make an Initialization Section near the top of your notebook that would contain all the definitions that are initialized. If a definition is a more extended routine you could develop it in a development Section and then when it works move it to the Initialization Section. 3) Again if you have material for a certain calculation, say, in a Section by itself you could just evaluate the entire Section when you reopen the notebook to get started again. You wouldn't have to make any of the definitions there Initializations cells. So Sectional organization and Initialization cells are convenient ways to organize your work. Later, when you develop a number of really useful routines, you could think of putting them into a Mathematica package, which isn't terribly difficult, and then any notebook that needed to use the routines in the package would just load the package near the top of the notebook, and this itself could be an Initialization cell. David Park djmpark at comcast.net http://home.comcast.net/~djmpark/index.html From: pedro.roberto at campus.ul.pt [mailto:pedro.roberto at campus.ul.pt] Hello, I'm just getting started on Mathematica and trying to define a function for later use. The function is just: test[x_]:=x^2 While I don't close mathematica, I can use the function on my notebooks but when I close it, the function disappers, I tried to save a .m file with it but It didn't work. What do I do? Thanks for time, Pedro