Re: Compile Fourier

• To: mathgroup at smc.vnet.net
• Subject: [mg64906] Re: Compile Fourier
• From: Peter Pein <petsie at dordos.net>
• Date: Tue, 7 Mar 2006 06:11:58 -0500 (EST)
• References: <duh209\$5kq\$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```Alberto Verga schrieb:
> The following piece of code gives an error message 'Compiled expression
> should be a rank 1 tensor of machine-size complex numbers'
>
>     Compile[{{m, _Real, 2}}, Fourier[m]][Table[N[i - j], {i, 4}, {j, 4}]]
>
> Does this mean that Fourier[] cannot be compiled with rank 2 arrays?
> My goal is to write a pseudospectral code to solve 2D PDE: compiling the
> time loop seems unavoidable if one wants reasonable performance.
>
> Thanks.
>
> Alberto Verga.
> Alberto.Verga at irphe.univ-mrs.fr
>
>
>
>
In[1]:=
Compile[{{m,_Real,2}},Fourier[m],{{_Fourier,_Complex,2}}][Table[N[i-j],{i,4},{j,4}]]
Out[1]=
{{0. + 0.*I, 2. + 2.*I, 2. + 0.*I, 2. - 2.*I}, {-2. - 2.*I, 0. + 0.*I, 0. + 0.*I, 0. + 0.*I},
{-2. + 0.*I, 0. + 0.*I, 0. + 0.*I, 0. + 0.*I}, {-2. + 2.*I, 0. + 0.*I, 0. + 0.*I, 0. + 0.*I}}

works :-)

```

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