Error: The first argument must be a scalar.

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Cantor Set 2019-1-22

评论： Cantor Set 2019-1-23

I defined a matrix of variables like this

X=sym('X', [4,1])
%it looks like this
X=[X1 X2 X3 X4]'

Then the code did some stuff on X to give a vector d of the form

d=[1-X1; 1-X2; 1-X3; 1]

Now I need to differentiat the ith element of d wrt the ith element of X, in other words I want to do this

I tried this

E=gradient(d, [X(1) X(2) X(3) X(4)]);

It gave me an error "The first argument must be a scalar"

So what should I do now?

Thanks!

Torsten 2019-1-22

dd = [diff(d(1),X(1)),diff(d(2),X(2)),diff(d(3),X(3)),diff(d(4),X(4))]

Cantor Set 2019-1-23

Thanks :)

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