Output matrix for simple function
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I'm brand new to Matlab, and have created a very simple function here to calculate an ion's equilibrium potential:
function y = equipotent(n,X1,X2)
y = (58/n) * log10(X1/X2);
I'd like to do two things: 1) vary X2 for a set of values (1-100) while keeping X1 and n constant. and 2) store all the outputs from the function in a vector for plotting X2 vs y.
Anything helps! Thanks!
回答（2 个）
the cyclist
2014-4-14
If you change your code to
function y = equipotent(n,X1,X2)
y = (58/n) * log10(X1./X2);
then it will give a vector output y for vector input X2, and you should be all set.
Sven
2014-4-14
Hi Derek,
MATLAB has some useful ways to do what you're trying to do. If you use the (.*) operator instead of (*), it will perform a vector multiplication.
Therefore you can adjust your function as follows:
function y = equipotent(n,X1,X2)
y = (58 ./ n) .* log10(X1 ./ X2);
Then you can just run commands:
y = equipotent(4, 3, X2)
figure
plot(X2,y)
Did that help you out?
4 个评论
Derek
2014-4-14
Ah, this sounds like the following code would help you:
n = 4;
X2 = (1:100)'; % Let's make it a vertical (100-by-1) vector
X1_set = 1:5; % Let's use 5 different values for X1
% So the result(s) can be collected in a 100-by-5 matrix
y_set = zeros(length(X2), length(X1_set));
for i = 1:length(X1_set)
y_set(:,i) = equipotent(n, X1_set(i), X2);
end
% And plot them
figure
plot(X2,y_set)
legend(num2str(X1_set'))
I'll update my answer accordingly. Is this what you were looking for?
Note that in your original question:
2) store all the outputs from the function in a vector for plotting X2 vs y
You only wanted to plot X2 (which is a 100-length vector) against y. In the original answer, putting the (.*) operator in the function lets you calculate y all-at-once so that y is also a 100-length vector. There should have been no need to run your function more than once.
In my comment above I've also showed how to store sets of y for different input via a loop. This is the only time where you'd need to run your function more than once (and therefore need to avoid overwriting your previous answer by putting y into columns of the y_set matrix.
Evangelia Lo
2021-11-12
I have one similar question ... I want ti make a function which will take p, v, d and D as input, and will calculate the pressure drop register (Dp), for d / D from 1 to d / D (derived from the input data), and in steps of (1/100 ) * (d / D)... How can i do it ?
Evangelia Lo
2021-11-12
The type of function is
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2021-11-12
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