Re: Change Rank in Compile
- To: mathgroup at smc.vnet.net
- Subject: [mg16057] Re: Change Rank in Compile
- From: Paul Abbott <paul at physics.uwa.edu.au>
- Date: Tue, 23 Feb 1999 03:45:16 -0500
- Organization: University of Western Australia
- References: <7ao4bi$s1u@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Peter Klamser wrote:
> Can I change Rank?
>
> sum$compiled=
> Compile[{{v,_Real,10}},
> Block[{i=1,s=0.0,x=0.0},s=0.0;Do[x=Take[v,i];s=s+x 2,{i,10}]]]
I don't fully understand what you are tring to do with this code but I
think you should have a look at FoldList. E.g., to compute cumulative
vector sums, you can use
FoldList[Plus, {0, 0}, {{0, 1}, {1, 2}}]
and I think that, essentially, this is what you are after.
> gives the error message
>
> Compile::"cset":
> "Variable \!\(x\) of type \!\({\"_Real\", 0}\) encountered in
> assignment \
> of type \!\({\"_Real\", 10}\)."
The assignment x=0.0 implicitly makes the variable x of type _Real.
However, the assignment x=Take[v,i] means that x is a List.
One point: before even trying to compile a Module it should work as a
Module -- and, if I make v a vector of Length 10, your code does not
work.
It might be a good idea to include sample input and output so that
others can follow exactly what you are trying to do.
Cheers,
Paul
____________________________________________________________________
Paul Abbott Phone: +61-8-9380-2734
Department of Physics Fax: +61-8-9380-1014
The University of Western Australia
Nedlands WA 6907 mailto:paul at physics.uwa.edu.au
AUSTRALIA http://www.physics.uwa.edu.au/~paul
God IS a weakly left-handed dice player
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