Convolution

Dear All,

  I'm not sure if this is the right place for this, so if not sorry.

  I have 2 matrixes (2x7) and i want to do convolution on them. When I
do the foureir transformation and then multiply them and finally do
the inverse fft I get a matrix of complex numbers. How do I turn these
numbers/matrix into a correlation coeff or something close to it.

  Also is fft-ing the best way to do this?

  I've include a little code to illistrate my exaple.

Cheers,

Paul

 > zy
           y
[1,] 10 0.00
[2,] 20 0.00
[3,] 30 0.25
[4,] 40 0.50
[5,] 50 0.25
[6,] 60 0.00
[7,] 70 0.00
> zx
          x
[1,] 10   0
[2,] 20   0
[3,] 30   0
[4,] 40 100
[5,] 50   0
[6,] 60   0
[7,] 70   0
> fft(fft(zx) * fft(zy), inverse=TRUE)
                      x
[1,] 147350+0i 70700+0i
[2,] 166600+0i 84840+0i
[3,] 176400+0i 98735+0i
[4,] 176400+0i 14385+0i
[5,] 166600+0i 28280+0i
[6,] 147350+0i 42420+0i
[7,] 118300+0i 56560+0i

On May 7, 5:56 am, PB0711 <hpben...@gmail.com> wrote:
> Dear All,
>
>   I'm not sure if this is the right place for this, so if not sorry.
>
>   I have 2 matrixes (2x7) and i want to do convolution on them. When I
> do the foureir transformation and then multiply them and finally do
> the inverse fft I get a matrix of complex numbers. How do I turn these
> numbers/matrix into a correlation coeff or something close to it.
>
>   Also is fft-ing the best way to do this?
>
>   I've include a little code to illistrate my exaple.
>
> Cheers,
>
> Paul
>
>  > zy
>            y
> [1,] 10 0.00
> [2,] 20 0.00
> [3,] 30 0.25
> [4,] 40 0.50
> [5,] 50 0.25
> [6,] 60 0.00
> [7,] 70 0.00> zx
>
>           x
> [1,] 10   0
> [2,] 20   0
> [3,] 30   0
> [4,] 40 100
> [5,] 50   0
> [6,] 60   0
> [7,] 70   0> fft(fft(zx) * fft(zy), inverse=TRUE)
>
>                       x
> [1,] 147350+0i 70700+0i
> [2,] 166600+0i 84840+0i
> [3,] 176400+0i 98735+0i
> [4,] 176400+0i 14385+0i
> [5,] 166600+0i 28280+0i
> [6,] 147350+0i 42420+0i
> [7,] 118300+0i 56560+0i

Do u want to do a 2-d convolution or just 1-d.

If 2-d is the case then you can use conv2 and if you
wanto to use fft then you can use fft2.

I would like to do a 2D convolution. I tried the fft2 and conv2
function but it didn't work. I'm working in 'R', I think I forgot to
say where my code was comming from, opps :|
Is that a matlab command?

Cheers,
Paul

> Do u want to do a 2-d convolution or just 1-d.
>
> If 2-d is the case then you can use conv2 and if you
> wanto to use fft then you can use fft2.- Hide quoted text -
>