Extracting matrix diagonal with diag(A)

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Irina
Irina on 19 Feb 2015
Commented: Irina on 19 Feb 2015
A simple function that used to run now gives an error message. What am I doing wrong?
>> a = eye(4,4);
>> diag(a)
Subscript indices must either be real positive integers or logicals.
>>

Accepted Answer

Evan
Evan on 19 Feb 2015
Edited: Evan on 19 Feb 2015
Does this fix your problem?
a = eye(4,4) == 1;
diag(a)
While the diag function works fine, if you have a variable named diag (not a good idea--give it a unique name that isn't the same as a builtin function), it expects a logical, not double, input for indexing.

More Answers (1)

Erik S.
Erik S. on 19 Feb 2015
Do you have another matrix in your workspace called diag?

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