Re: What does & mean?
- To: mathgroup at smc.vnet.net
- Subject: [mg107081] Re: What does & mean?
- From: Bill Rowe <readnews at sbcglobal.net>
- Date: Tue, 2 Feb 2010 03:28:36 -0500 (EST)
On 2/1/10 at 6:14 AM, micknudsen at gmail.com (Michael Knudsen) wrote:
>I have recently bought Mathematica, and I have a really tough time
>getting started. I'm reading the various documents found under
>"Complete Documentation" at the Mathematica homepage, but it doesn't
>feel like the right place to start.
>For example, I'm now trying to solve some simple differential
>equations, and the documentation provides the following example:
>A = {{4, -6}, {1,-1}};
>X[t_] = {x[t], y[t]}; system = MapThread[#1 == #2 &, {X'[t],
>A.X[t]}];
>sol = DSolve[system, {x,y}, t]
>However, there is no explanation of how & works here (and it isn't
>in the MapThread documentation either). Where should one start
>reading in order to understand basic constructs like this? This
>particular example is really nasty, since & is generally ignored by
>search engines.
The "&" character is used here to define a pure function. In
this case, the pure function equates the two arguments given to
it. More information on how "&" works can be found by searching
on either the character "&" or Function in the Documentation
Center. At the bottom of the documentation page is a set of
links to tutorials with more information.