[Scilab-users] Peaks and positions

[Stefan Du Rietz]

It means the last element of the vector/matrix.

/Stefan

On 2013-01-28 22:30, Berns Buenaobra wrote:
--------------------
> Hi Samuel:
>
> I'd like to understand  the "$" inside the would mean from the script?
>
> Thanks,
> Berns B.
>
>
> On Sun, Jan 27, 2013 at 12:46 AM, Samuel Gougeon <sgougeon at free.fr
> <mailto:sgougeon at free.fr>> wrote:
>
>     Le 26/01/2013 17:00, constantina a écrit :
>>     Sorry, I know is a basic question, i now the answer in matlab but not in
>>     scilab.... What is the function that let me find "peaks " in a matrix and
>>     the position of the peaks???
>     Here is a possible solution, including peaks on the borders:
>
>     m = rand(6,6)
>     M = [m(2,:) ; m ; m($-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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