How can I use a function on a series of values?

1 Ansicht (letzte 30 Tage)
Nishant Singhal
Nishant Singhal am 10 Dez. 2016
Beantwortet: Walter Roberson am 10 Dez. 2016
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?

Antworten (2)

David Barry
David Barry am 10 Dez. 2016
a = arrayfun(f, n(:,1), 'UniformOutput', false);
n(:,2:3) = [a{:}]';

Walter Roberson
Walter Roberson am 10 Dez. 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)

Kategorien

Mehr zu Numerical Integration and Differential Equations finden Sie in Help Center und File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by