# Error in loop: left and right sides have a different number of elements

1 Ansicht (letzte 30 Tage)
Miriam am 27 Okt. 2022
Kommentiert: Miriam am 27 Okt. 2022
I wanna make a loop out of the following lines:
dt=1;
a0= 0.01*sqrt(d/D)*Fr/D*u*dt;
a1=0;
a2=7.07;
a3=4.45/tan(phi);
a4=0.786/(tan(phi)*tan(phi));
p=[a4 a3 a2 a1 a0];
Zvs1=real(roots(p))*D
dt=2;
a0= 0.01*sqrt(d/D)*Fr/D*u*dt;
a1=0;
a2=7.07;
a3=4.45/tan(phi);
a4=0.786/(tan(phi)*tan(phi));
p=[a4 a3 a2 a1 a0];
Zvs2=real(roots(p))*D
dt=3;
a0= 0.01*sqrt(d/D)*Fr/D*u*dt;
a1=0;
a2=7.07;
a3=4.45/tan(phi);
a4=0.786/(tan(phi)*tan(phi));
p=[a4 a3 a2 a1 a0];
Zvs3=real(roots(p))*D
dt=4;
a0= 0.01*sqrt(d/D)*Fr/D*u*dt;
a1=0;
a2=7.07;
a3=4.45/tan(phi);
a4=0.786/(tan(phi)*tan(phi));
p=[a4 a3 a2 a1 a0];
Zvs4=real(roots(p))*D
For every Zvs i get for solutions (Zvs (4,1)). I tried like this:
dt = [1:1:4];
Zvs = NaN(length(dt),4);
for i=1:length(dt)
a0= 0.01*sqrt(d/D)*Fr/D*u*dt;
a1=0;
a2=7.07;
a3=4.45/tan(phi);
a4=0.786/(tan(phi)*tan(phi));
p=[a4 a3 a2 a1 a0];
Zvs (i)=real(roots(p))*D
end
I get this Error:
Unable to perform assignment because the left and right sides have a
different number of elements.
Error in Skript (line 26)
Zvs (i)=real(roots(p))*D
I know that the problem ist the different size from Zvs (i), its 1x1 and not 1x4. But i don't know how to fix it.
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### Akzeptierte Antwort

RAJA SEKHAR BATTU am 27 Okt. 2022
Bearbeitet: RAJA SEKHAR BATTU am 27 Okt. 2022
You can pre assign the variables to empty or zeros before loop to save the values efficiently. I will make some modifications please check if it works.
a0, p and Zvs variables are changing every iteration
dt = [1:1:4];
Zvs = zeros(4,length(dt));
a0 = zeros(1,length(dt));
p = zeros(length(dt),5);
for i=1:length(dt)
a0(i)= 0.01*sqrt(d/D)*Fr/D*u*dt(i);
a1=0;
a2=7.07;
a3=4.45/tan(phi);
a4=0.786/(tan(phi)*tan(phi));
p(i,:)=[a4 a3 a2 a1 a0(i)];
Zvs(:,i)=real(roots(p(i,:)))*D;
end
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Miriam am 27 Okt. 2022
I got it, now it works. Thanks!

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