How to get rid of for loop?

Question

Yen Tien Yap 2021-6-21

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/861170-how-to-get-rid-of-for-loop

编辑： SALAH ALRABEEI 2021-6-21

Hi, may I know how to get rid of the for loop by using logical indexing? Thnak you.

function [x_vals,y_vals,I,A]=monte_carlo_syms(x,y,f,g)
x_vals=unifrnd(0,1,[200,1]);
y_vals=unifrnd(0,1,[200,1]);
for i=1:length(x_vals)
    f_val=subs(f,x,x_vals(i));
    f_val=double(subs(f_val,y,y_vals(i)));
    g_val=subs(g,x,x_vals(i));
    g_val=double(subs(g_val,y,y_vals(i)));
    if f_val> g_val
        I(i,1)=true;
        
    else
        I(i,1)=false;
        
    end
end
hold on 
scatter(x_vals(I==1),y_vals(I==1),'x','g')
scatter(x_vals(I==0),y_vals(I==0),'x','r')
A=sum(I)/length(x_vals);
    
end

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KSSV 2021-6-21

What are f, g functions?

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Answer 1

SALAH ALRABEEI 2021-6-21

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/861170-how-to-get-rid-of-for-loop#answer_729480

编辑：SALAH ALRABEEI 2021-6-21

在 MATLAB Online 中打开

function [x_vals,y_vals,I,A]=monte_carlo_syms(x,y,f,g)
x_vals=unifrnd(0,1,[200,1]);
y_vals=unifrnd(0,1,[200,1]);
I = nan*length(x_vals);
f_val = subs(f,{x,y},{x_vals,y_vals});
g_val = subs(g,{x,y},{x_vals,y_vals});
mask = f_val> g_val;
I(mask,1)=1;
I(~mask,1)=0;
scatter(x_vals(mask),y_vals(mask),'x','g')
scatter(x_vals(~mask),y_vals(~mask),'x','r')
A=sum(I)/length(x_vals);
end