How can I use a function on a series of values?
1 view (last 30 days)
Show older comments
So I've got a function y=f(x), where y=roots([1 0 x]).
I have a matrix n, which is:
-1 0 0
-2 0 0
-3 0 0
-4 0 0
-5 0 0
-6 0 0
-7 0 0
-8 0 0
-9 0 0
-10 0 0
I'm trying to have columns 2 and 3 be the solutions to the function.
Here's what I tried:
>> n(:,2:3)=f(n(:,1))
It keeps saying 'error using horzcat'.
But if I do it manually, one by one, it works, for example:
>> n(1,2:3)=f(n(1,1))
This would make row 1 of n (-1, -1, 1), which is correct.
How can I make it work for all of the rows at once?
0 Comments
Answers (2)
David Barry
on 10 Dec 2016
a = arrayfun(f, n(:,1), 'UniformOutput', false);
n(:,2:3) = [a{:}]';
0 Comments
Walter Roberson
on 10 Dec 2016
You cannot. roots() only works with one row at a time.
However, you are working with a simple quadratic so you can easily construct the quadratic solution formula and vectorize that. A moment of thought shows that the solutions will be +/- sqrt(-x)
0 Comments
See Also
Categories
Find more on Logical 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!