Re: Select elements according to the index

[Henry F. Mollet]

octave:24> a=[1 2 3; 4 5 6]
a =
  1  2  3
  4  5  6
octave:25> b=[.1 .2 .3 .4 .5 .6 .7 .8]
b =
  0.10000  0.20000  0.30000  0.40000  0.50000  0.60000  0.70000  0.80000
octave:26> c=b(a)
c =
  0.10000  0.20000  0.30000
  0.40000  0.50000  0.60000
Works on
GNU Octave, version 2.1.46 (powerpc-apple-darwin6.6).
Henry

> 
> What version of Octave are you using ?  This is from 2.1.64 Debian Testing.
> 
> octave:1> a=[1 2 3; 4 5 6];
> octave:2> b=[.1 .2 .3 .4 .5 .6 .7 .8];
> octave:3> c=b(a)
> c =
> 
> 0.10000  0.20000  0.30000
> 0.40000  0.50000  0.60000
> 
> 
> Todd
> 

on 2/13/05 8:04 AM, Todd Neal at address@hidden wrote:

> On Sun, 13 Feb 2005 13:32:25 -0000, Chen, Minyu <address@hidden> wrote:
> ...
>> Suppose I have an index matrix of 2 by 3, e.g. a=[1 2 3; 4 5 6]
>> 
>> And have a vector of 1 by 8, e.g. b=[.1 .2 .3 .4 .5 .6 .7 .8]
>> 
>> And I want to create a matrix c of 2 by 3 (the same dimension of a),
>> with c(i,j)=b(a(i,j)), that's being said:
>> 
>> c=[.1 .2 .3; .4 .5 .6]
>> 
>> In matlab, as memory serves correctly, I can do it by typing:
>> 
>> c=b(a)
>> 
>> but this command in Octave will generate only a vector of 1 by 6:
>> 
>> c=[.1 .4 .2 .5 .3 .6]
>> 
>> How can I get the matrix I want?
>> 
>> Many Thanks,
>> Minyu Chen
> 

> 



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