Re: Thread function over matrix elements?

• To: mathgroup at smc.vnet.net
• Subject: [mg69915] Re: [mg69865] Thread function over matrix elements?
• From: Murray Eisenberg <murray at math.umass.edu>
• Date: Wed, 27 Sep 2006 06:05:13 -0400 (EDT)
• Organization: Mathematics & Statistics, Univ. of Mass./Amherst
• References: <200609260459.AAA01827@smc.vnet.net>

```If f is already a function that has attribute Listable, then you need
only use:

f[mat]

For example, Sin[mat].  And if f does not have attribute Listable, you
could give it that attribute:

SetAttributes[f, Listable]
mat=Table[i+j,{i,0,2},{j,0,2}]
f[mat]
{{f[0],f[1],f[2]},{f[1],f[2],f[3]},{f[2],f[3],f[4]}}

ben wrote:
> Dear all,
>
> how do I thread a function over all elements of a matrix?
> This piece of code works, but I doubt its the way i am supposed to do
> this
>
> mat=Table[i+j,{i,0,2},{j,0,2}]
>
> Map[Map[f[#]&,#]&,mat]
>
> I tried
>
> Map[f[#]&,mat,2]
> Apply[f[#]&,mat,2]
>
> but they give weird results.
>
> Cheers
> Ben
>
>

--
Murray Eisenberg                     murray at math.umass.edu
Mathematics & Statistics Dept.
Lederle Graduate Research Tower      phone 413 549-1020 (H)
University of Massachusetts                413 545-2859 (W)
710 North Pleasant Street            fax   413 545-1801
Amherst, MA 01003-9305

```

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