Distance formula using while loop

so i given a data file, I was able to call in these values into Matlab input

these cells are empty because user chooses what values to input I have to call out 5 values for each column fo i (Xa,Ya,Xb,Yb, and t) so will using

while i <= 8
  Di = sqrt((Xb-Xa)^2+(Yb-Ya)^2)) 
end

will this code give me D1 to D8? also how would I be able to multiple each t(i) into to corresponding Dis???

Answer 1

[Jan]

Do not create a set of variables called "D1, D2, ...". See

https://www.mathworks.com/matlabcentral/answers/57445-faq-how-can-i-create-variables-a1-a2-a10-in-a-loop

and with much more details:

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

This is more efficient (posted by Youssef already):

D = sqrt((Xb - Xa) .^ 2 + (Yb - Ya) .^ 2))

Then use D(2), D(2), ... instead of D1, D2, ...

Answer 2

[Youssef Khmou]

In the given formulae, are the variables vectors? if it is the case, then you need to use index in the loop for each variable to select the ith value at ith iteration:

while ii<=8

D(ii)=sqrt((Xb(ii)-Xa(ii))^2+(Yb(ii)-Ya(ii))^2);

ii=ii+1;

end

in compact form you can directly compute the distance using element wise operation:

D=sqrt(Xa-Xb).^2+(Yb-Ya).^2);

to multiply each value of D with its corresonding value of t use the compact form:

R=D.*t;