[Scilab-users] Peaks and positions

[Berns Buenaobra]

Hi Samuel:

I'd like to understand  the "$" inside the would mean from the script?

Thanks,
Berns B.


On Sun, Jan 27, 2013 at 12:46 AM, Samuel Gougeon <sgougeon at free.fr> wrote:

>  Le 26/01/2013 17:00, constantina a écrit :
>
> Sorry, I know is a basic question, i now the answer in matlab but not in
> scilab.... What is the function that let me find "peaks " in a matrix and
> the position of the peaks???
>
>  Here is a possible solution, including peaks on the borders:
>
> m = rand(6,6)
> M = [m(2,:) ; m ; m($-1,:) ];
> M = [M(:,2)  M  M(:,$-1)];
> pC = M(2:$-1,2:$-1)>M(1:$-2,2:$-1) & M(2:$-1,2:$-1)>M(3:$,2:$-1);
> pR = M(2:$-1,2:$-1)>M(2:$-1,1:$-2) & M(2:$-1,2:$-1)>M(2:$-1,3:$);
> isPeak = pC & pR
> find(isPeak)      // returns linearized indices of peaks
> m(~isPeak) = 0 //  to show only peaks
>
> giving:
>
> -->m = rand(6,6)
>  m  =
>     0.0437334    0.7783129    0.8415518    0.5618661    0.3873779
> 0.2615761
>     0.4818509    0.2119030    0.4062025    0.5896177    0.9222899
> 0.4993494
>     0.2639556    0.1121355    0.4094825    0.6853980    0.9488184
> 0.2638578
>     0.4148104    0.6856896    0.8784126    0.8906225    0.3435337
> 0.5253563
>     0.2806498    0.1531217    0.1138360    0.5042213    0.3760119
> 0.5376230
>     0.1280058    0.6970851    0.1998338    0.3493615    0.7340941
> 0.1199926
>
> -->M = [m(2,:) ; m ; m($-1,:) ];
> -->M = [M(:,2)  M  M(:,$-1)];
> -->pC = M(2:$-1,2:$-1)>M(1:$-2,2:$-1) & M(2:$-1,2:$-1)>M(3:$,2:$-1);
> -->pR = M(2:$-1,2:$-1)>M(2:$-1,1:$-2) & M(2:$-1,2:$-1)>M(2:$-1,3:$);
> -->isPeak = pC & pR
>  isPeak  =
>   F F T F F F
>   T F F F F F
>   F F F F T F
>   F F F T F F
>   F F F F F T
>   F T F F T F
>
> -->find(isPeak)      // returns linearized indices of peaks
>  ans  =
>     2.    12.    13.    22.    27.    30.    35.
>
> -->m(~isPeak) = 0 //  to show only peaks
>  m  =
>     0.           0.           0.8415518    0.           0.
> 0.
>     0.4818509    0.           0.           0.           0.
> 0.
>     0.           0.           0.           0.           0.9488184
> 0.
>     0.           0.           0.           0.8906225    0.
> 0.
>     0.           0.           0.           0.           0.
> 0.5376230
>     0.           0.6970851    0.           0.           0.7340941    0.
>
>
> Regards
> Samuel
>
>
>
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