Re: "vector" Map[] / functional outer product?

• To: mathgroup at smc.vnet.net
• Subject: [mg83773] Re: "vector" Map[] / functional outer product?
• From: Mitch Murphy <mitch at lemma.ca>
• Date: Fri, 30 Nov 2007 05:19:11 -0500 (EST)
• References: <fim8tq\$rmd\$1@smc.vnet.net> <474ED0C0.9030008@gmail.com>

```based on the solution from Jean-Marc Gulliet, here's a slight
my issue perfectly without having to type in esc sequences for infix
operators

Unprotect[Map];
Map[f_List, a_List] := Transpose@Outer[Compose, f, a]
Protect[Map];

{f, g} /@ {a, b, c}

-> {{f[a],g[a]},{f[b],g[b]},{f[c],g[c]}}

cheers,
Mitch

On Nov 29, 2007, at 09:46, Jean-Marc Gulliet wrote:

> Mitch Murphy wrote:
>> greetings,
>> is there a simpler way to express
>> 	{f@#,g@#}& /@ {a,b,c}
>> 	-> {{f[a],g[a]},{f[b],g[b]},{f[c],g[c]}}
>> ie. is there some mathematica function ??? such that
>> 	{f,g} ??? {a,b,c}
>> 	-> {{f[a],g[a]},{f[b],g[b]},{f[c],g[c]}}
>
> <snip>
>
> The following expression (In[1]) will return the desired list
> without the burden of passing explicitly any arguments to your
> functions.
>
> In[1]:= Outer[Compose, {f, g}, {a, b, c}] // Transpose
>
> Out[1]= {{f[a], g[a]}, {f[b], g[b]}, {f[c], g[c]}}
>
> Note that if you want a nice infix notation, you could add some
> meaning to a symbol without any built-in meaning, such as CirclePlus
> (On the keyboard, you can enter the symbol CirclePlus as Esc c+ Esc
> --- i.e. escape key followed by c followed by + followed by the
> escape key.)
>
> In[2]:= CirclePlus[f_, a_] := Transpose[Outer[Compose, f, a]]
>
> In[3]:= {f, g}\[CirclePlus]{a, b, c}
>
> Out[3]= {{f[a], g[a]}, {f[b], g[b]}, {f[c], g[c]}}
>
> Regards,
> --
> Jean-Marc

```

• Prev by Date: Re: A problem with FindRoot
• Next by Date: Re: "vector" Map[] / functional outer product?
• Previous by thread: Re: "vector" Map[] / functional outer product?
• Next by thread: Re: "vector" Map[] / functional outer product?