MathGroup Archive 2011

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: Matrices as operators

  • To: mathgroup at
  • Subject: [mg123060] Re: Matrices as operators
  • From: Ray Koopman <koopman at>
  • Date: Tue, 22 Nov 2011 05:34:28 -0500 (EST)
  • Delivered-to:
  • References: <jaal4e$12d$>

On Nov 20, 2:34 am, Chris Young <c... at> wrote:
> I'd like to be able to abbreviate matrices such as rotation matrices
> so that I don't have to repeat the argument. This way I can pass in
> more complicated arguments and it also shows the structure of the
> transformation more clearly.
> Through[( {
>     {Cos, -Sin},
>     {Sin, Cos}
>    } )[=CE=B8]]
> will get me partway there:
> Out: {{Cos, -Sin}[=CE=B8], {Sin, Cos}[=CE=B8]}
> I have to apply Thread and Through again to finally get what I want:
> In: Thread[Through[{{Cos, -Sin}[=CE=B8], {Sin, Cos}[=CE=B8]}]]
> Out: {{Cos[=CE=B8], (-Sin)[=CE=B8]}, {Sin[=CE=B8], Cos[=CE=B8]}}
> Is there a shortcut way to do this all in one step?
> Thanks very much for any help.
> Chris Young
> c... at

If you're worried about redundant calculations when the matrices
are bigger than 2 x 2 and the functions are more complicated than
Sin and Cos, try something like

R[t_] := {{#1,-#2},{#2,#1}}&[Cos@t,Sin@t]

  • Prev by Date: Re: Elliptical gear calculations
  • Next by Date: Re: Is it possible to define new color schemes?
  • Previous by thread: Re: Matrices as operators
  • Next by thread: Re: Matrices as operators