First argument of XCORR must be a vector?

In the help description of cross-correlation command XCORR, the first argument can be specified as a vector, matrix, or multidimensional array.

But my Matlab 2020b and matlab online threw an error: Error using xcorr (line 93) First argument must be a vector.

The test code is simple as:

xcorr(magic(4), [1; 2; 3;4])

Answer 1

[Walter Roberson]

Yes, the first parameter to xcorr can be a vector, matrix, or multidimensional array. However, if you look at https://www.mathworks.com/help/matlab/ref/xcorr.html#description you will see that in the case that you pass in two parameters, then both parameters must be vectors.

xcorr(x,y)  --> must both be vector
xcorr(x)    --> not restricted to vector

[Zhangjun Yu]

Thank you very much. I found it : r = xcorr(x) returns the autocorrelation sequence of x. If x is a matrix, then r is a matrix whose columns contain the autocorrelation and cross-correlation sequences for all combinations of the columns of x.