Index exceeds the number of array elements (1).

Question

Heya :) 2020-11-25

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/661793-index-exceeds-the-number-of-array-elements-1

评论： Heya :) 2020-11-25

I am unable to spot why I am getting an error. Please help to resolve the error.

x1_rec(1)=x1(1);
x2_rec(1)=x2(1);
y1_rec(1)=y1(1);
y2_rec(1)=y2(1);
%value of constants
%a1=x1
a1=ksaix1(1);
a2=ksaix1(2);
a3=ksaix1(3);
a4=ksaix1(4);
a5=ksaix1(5);
a6=ksaix1(6);
a7=ksaix1(7);
a8=ksaix1(8);
a9=ksaix1(9);
a10=ksaix1(10);
a11=ksaix1(11);
a12=ksaix1(12);
a13=ksaix1(13);
a14=ksaix1(14);
a15=ksaix1(15);
a16=ksaix1(16);
a17=ksaix1(17);
a18=ksaix1(18);
a19=ksaix1(19);
a20=ksaix1(20);
a21=ksaix1(21);
a22=ksaix1(22);
a23=ksaix1(23);
a24=ksaix1(24);
a25=ksaix1(25);
a26=ksaix1(26);
a27=ksaix1(27);
a28=ksaix1(28);
a29=ksaix1(29);
a30=ksaix1(30);
a31=ksaix1(31);
a32=ksaix1(32);
%c=x2
c1=ksaix2(1);
c2=ksaix2(2);
c3=ksaix2(3);
c4=ksaix2(4);
c5=ksaix2(5);
c6=ksaix2(6);
c7=ksaix2(7);
c8=ksaix2(8);
c9=ksaix2(9);
c10=ksaix2(10);
c11=ksaix2(11);
c12=ksaix2(12);
c13=ksaix2(13);
c14=ksaix2(14);
c15=ksaix2(15);
c16=ksaix2(16);
c17=ksaix2(17);
c18=ksaix2(18);
c19=ksaix2(19);
c20=ksaix2(20);
c21=ksaix2(21);
c22=ksaix2(22);
c23=ksaix2(23);
c24=ksaix2(24);
c25=ksaix2(25);
c26=ksaix2(26);
c27=ksaix2(27);
c28=ksaix2(28);
c29=ksaix2(29);
c30=ksaix2(30);
c31=ksaix2(31);
c32=ksaix2(32);
h=0.1;   %step size
t=0:h:50;
%ode
p=@(t,x1_rec,y1_rec,x2_rec,y2_rec) a1+a2*x1_rec+a3*x2_rec+a4*y1_rec+a5*y2_rec+a6*x1_rec*x2_rec+a7*y1_rec*y2_rec+a8*x1_rec*y1_rec+a9*x1_rec*y2_rec+a10*x2_rec*y1_rec+a11*x2_rec*y2_rec+a12*x1_rec*x2_rec*y1_rec+a13*x1_rec*x2_rec*y2_rec+a14*x1_rec*y1_rec*y2_rec+a15*x2_rec*y1_rec*y2_rec+a16*x1_rec*x2_rec*y1_rec*y2_rec+a17*x1_rec^2+a18*x2_rec^2+a19*y1_rec^2+a20*y2_rec^2+a21*x1_rec^2*x2_rec+a22*x1_rec^2*y1_rec+a23*x1_rec^2*y2_rec+a24*x2_rec^2*x1_rec+a25*x2_rec^2*y1_rec+a26*x2_rec^2*y2_rec+a27*y1_rec^2*x1_rec+a28*y1_rec^2*x2_rec+a29*y1_rec^2*y2_rec+a30*y2_rec^2*x1_rec+a31*y2_rec^2*x2_rec+a32*y2_rec^2*y1_rec;
q=@(t,x1_rec,y1_rec,x2_rec,y2_rec) c1+c2*x1_rec+c3*x2_rec+c4*y1_rec+c5*y2_rec+c6*x1_rec*x2_rec+c7*y1_rec*y2_rec+c8*x1_rec*y1_rec+c9*x1_rec*y2_rec+c10*x2_rec*y1_rec+c11*x2_rec*y2_rec+c12*x1_rec*x2_rec*y1_rec+c13*x1_rec*x2_rec*y2_rec+c14*x1_rec*y1_rec*y2_rec+c15*x2_rec*y1_rec*y2_rec+c16*x1_rec*x2_rec*y1_rec*y2_rec+c17*x1_rec^2+c18*x2_rec^2+c19*y1_rec^2+c20*y2_rec^2+c21*x1_rec^2*x2_rec+c22*x1_rec^2*y1_rec+c23*x1_rec^2*y2_rec+c24*x2_rec^2*x1_rec+c25*x2_rec^2*y1_rec+c26*x2_rec^2*y2_rec+c27*y1_rec^2*x1_rec+c28*y1_rec^2*x2_rec+c29*y1_rec^2*y2_rec+c30*y2_rec^2*x1_rec+c31*y2_rec^2*x2_rec+c32*y2_rec^2*y1_rec;
%loop
for i=1:(length(t)-1)
    k1=p(t(i),x1_rec(i),y1_rec(i),x2_rec(i),y2_rec(i));
    l1=q(t(i),x1_rec(i),y1_rec(i),x2_rec(i),y2_rec(i));
 
    
    k2=p(t(i)+h/2,(x1_rec(i)+(h/2)*k1),(y1_rec(i)+(h/2)*l1),(x2_rec(i)+(h/2)*k1),(y2_rec(i)+(h/2)*l1));
    l2=q(t(i)+h/2,(x1_rec(i)+(h/2)*k1),(y1_rec(i)+(h/2)*l1),(x2_rec(i)+(h/2)*k1),(y2_rec(i)+(h/2)*l1));
      
    k3=p(t(i)+h/2,(x1_rec(i)+(h/2)*k2),(y1_rec(i)+(h/2)*l2),(x2_rec(i)+(h/2)*k2),(y2_rec(i)+(h/2)*l2));
    l3=q(t(i)+h/2,(x1_rec(i)+(h/2)*k2),(y1_rec(i)+(h/2)*l2),(x2_rec(i)+(h/2)*k2),(y2_rec(i)+(h/2)*l2));
      
    k4=p(t(i)+h,(x1_rec(i)+k3*h),(y1_rec(i)+l3*h),(x2_rec(i)+k3*h),(y2_rec(i)+l3*h));
    l4=q(t(i)+h,(x1_rec(i)+k3*h),(y1_rec(i)+l3*h),(x2_rec(i)+k3*h),(y2_rec(i)+l3*h));
    
      x1_rec(i+1) = x1_rec(i) + h*(k1+2*k2+2*k3+k4)/6;
      %y1(i+1) = y1(i) + h*(l1+2*l2+2*l3+l4)/6;
      x2_rec(i+1) = x2_rec(i) + h*(k1+2*k2+2*k3+k4)/6;
      %y2(i+1) = y2(i) + h*(l1+2*l2+2*l3+l4)/6;
end
plot(x1_rec(1:length(x1)),'r','LineWidth',2)
plot(x2_rec(1:length(x2)),'r','LineWidth',2)
%%%%%Error%%%%
Index exceeds the number of array elements (1).
Error in coup (line 333)
    k1=p(t(i),x1_rec(i),y1_rec(i),x2_rec(i),y2_rec(i));

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Answer 1

KSSV 2020-11-25

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/661793-index-exceeds-the-number-of-array-elements-1#answer_555588

在 MATLAB Online 中打开

The error is clear...you are trying to extract more number of elements than present int he array.

A = rand(1,10) ; 
A(1)    % no error 
A(5)    % no error 
A(end)  % no error 
A(11)   % error, as there is no 11th element 

Your code is very long and also you are accessing some local data in between which we don't have access to. So we cannot help you exact on the point. But the error occurs due to the reason mentioned above.