How can I vectorize this Nested for loop

1 回表示 (過去 30 日間)
Tulio
Tulio 2017 年 5 月 29 日

I'm trying to vectorize the inner loop but I'm not being able to.

 for i = 1:NTS          
    U(1) = 0;
    V(1) = 0;
    U(end)=1;
    V(end)=1;
    for j = 2:NAS-1
        U(j) = (b(j) * U(j-1) + a(j) * UOld(j) + c(j) * UOld(j+1)) / gamma(j);
         V(NAS-j+1) = (b(NAS-j+1) * VOld(NAS-j+1-1) + a(NAS-j+1) * VOld(NAS-j+1) + c(NAS-j+1) * V(NAS-j+1+1)) / gamma(NAS-j+1);
    end
end

I've tried the following code but I get a wrong result, can someone please help me out if that?

 U(2:NAS-1) = ((b(2:NAS-1) .* U(1:NAS-2) + a(2:NAS-1) .* UOld(2:NAS-1) + c(2:NAS-1) .* UOld(3:NAS)) ./ gamma(2:NAS-1));
 V(NAS-1:-1:2) = ((b(NAS-1:-1:2) .* VOld(NAS-2:-1:1) + a(NAS-1:-1:2) .* VOld(NAS-1:-1:2) + c(NAS-1:-1:2) .* 
 V(NAS:-1:3)) ./ gamma(NAS-1:-1:2));
    clc
    clear
    NTS=1;
    NAS=10;
    U=rand(1,10)*100;
    V=U;
    UU=zeros(1,10);
    VV=zeros(1,10);
    Gamma=ones(1,100)*(1-10.05);
    a=ones(1,10)*(1-0.05);
    b=ones(1,10)*(1-0.15);
    c=ones(1,10)*(1-0.35);
    UOld=U;
    VOld=V;
    UU=U;
    VV=V;
    for i=1:NTS
      UU(2:NAS-1) = ((b(2:NAS-1) .* UU(1:NAS-2) + a(2:NAS-1) .* UOld(2:NAS-1) + c(2:NAS-1) .* UOld(3:NAS)) ./ gamma(2:NAS-1));
      VV(NAS-1:-1:2) = ((b(NAS-1:-1:2) .* VOld(NAS-2:-1:1) + a(NAS-1:-1:2) .* VOld(NAS-1:-1:2) + c(NAS-1:-1:2) .* VV(NAS:-1:3)) ./ gamma(NAS-1:-1:2));
        for j = 2:NAS-1
            U(j) = (b(j) * U(j-1) + a(j) * UOld(j) + c(j) * UOld(j+1)) / gamma(j);
            V(NAS-j+1) = (b(NAS-j+1) * VOld(NAS-j+1-1) + a(NAS-j+1) * VOld(NAS-j+1) + c(NAS-j+1) * V(NAS-j+1+1)) / gamma(NAS-j+1);
        end
        display(sum(U(2:NAS-1)'-UU(2:NAS-1)'));
        display(sum(V(2:NAS-1)'-VV(2:NAS-1)'));
    end
    display([U' UU']);
    display([V' VV']);

回答 (0 件)

カテゴリ

Help Center および File ExchangeGet Started with MATLAB についてさらに検索

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by