Please help me understand the use of dot operator
570 views (last 30 days)
Show older comments
Tsansoterra
on 18 Feb 2020
Commented: Star Strider
on 18 Feb 2020
Hello. I have been having this same problem in a lot of the homework assignments I have been given so far.
What I am trying to do is use the while loop to create values for J, and in the same loop I am trying to use those values of
J to create a new array with the values from tau.
clc; clear ; clear all
F = 10; %Newtons
T = F*0.1 ; %Work
r = 0:5; %mm
i = 1
while i < 6
J = (.5*pi)*r.^4
tau(i) = (T*r)/J
i = i + 1;
end
2 Comments
Accepted Answer
Star Strider
on 18 Feb 2020
The dot operator, used with multiplication, division, and exponentiation, creates element-wise oiperations. See Array vs. Matrix Operations for a full explanation.
The one exception to that is the use of the dot operator in creating matrix transposes. The ‘regular’ matrix transpose (') creates the complex-conjugate transpose of a complex vector or matrix. Using the (.') creates the transpose without doing the complex-conjugate operation.
3 Comments
More Answers (1)
David Hill
on 18 Feb 2020
Not sure what you want tau to be. Currently you have an array (T*r) divided by another array (J). If you want to generate a tau matrix, then:
tau(i,:)=(T*r)./J;
If tau is suppose to be a 6 element array, then I suppect what you meant was:
F = 10; %Newtons
T = F*0.1 ; %Work
r = 0:5; %mm
J = (.5*pi)*r.^4;
tau = (T*r)./J;%need ./for element-wise operations
See Also
Categories
Find more on Loops and Conditional Statements in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!