linalg:mean

(linalg:mean array &key axis keepdims)

Returns the arithmetic mean of every element: the linalg:sum divided by the linalg:size. Like a reduction in numpy, the result follows the element type: a packed double-float array (anything built by a linalg constructor) gives a double, while a plain integer array gives an exact rational.

With an integer :axis (negative counts from the end) it averages along that axis instead, following exactly the axis and :keepdims rules of linalg:sum: the axis is dropped from the result (kept with extent 1 under a non-nil :keepdims), and a vector without :keepdims reduces to the scalar itself.