How to define a function that can handle a vector/matrix
Subject: How to define a function that can handle a vector/matrix
From: Fabian Schuh
Date: Sun, 4 Jun 2006 18:28:55 +0200
Am Sunday, 4. June 2006 18:23 schrieb Robert Dodier:
> On 6/4/06, Fabian Schuh <Fabian.Schuh at gmx.de> wrote:
> > f(x) := matrix(
> > [x_1 + x_2] ,
> > [x_1 - x_2]
> > );
>
> Subscripted variables are written with square brackets,
> e.g. x[1], x[2], etc.
>
> So in this example,
>
> f (x) := matrix ([x[1] + x[2]], [x[1] - x[2]]);
>
> x : matrix ([1], [2]);
>
> f (x); => matrix ([[3]], [[-1]])
>
> y : [1, 2];
>
> f (y); => matrix ([3], [-1]) <-- Note that this is different from f (x)
>
> When x is a matrix, x[i] (i.e., with one subscript) is a list,
> namely the elements in row i. x[i] is a list even if the row
> contains just one element. So I'm guessing in this example
> you want the argument to be a list (like y) and not a matrix.
>
> Hope this helps,
Yhea .. it does.
Thx alot.
> Robert Dodier
-- Fabian Schuh