!argmax/!argmin requires tensor to be copied.

[hikettei]

In the function trainer:

(defun valid (trainer dataset batch-size)
  "Valid trainer"
  (let ((count 0)
	(correct 0))
    (loop for index fixnum upfrom 0 below (get-dataset-length dataset) by batch-size
	  do (let* ((ds (get-dataset dataset index))
		    (x (car ds))
		    (y (second ds))
		    (out (const (value (call (slot-value trainer 'model) x))))
		    (out-labels (!argmax out))
		    (y-labels   (!argmax (const (copy-mat (data y)))))) ; <--- Here
	       (with-facets ((out-labels ((data out-labels) 'backing-array :direction :input))
			     (y-labels   ((data y-labels) 'backing-array :direction :input)))
		 (loop for i below (length out-labels)
		       do (progn
			    (incf count 1)
			    (if (= (aref out-labels i) (aref y-labels i))
				(incf correct 1)
				(incf correct 0)))))))
	     (format t "Accuracy:~a~C" (coerce (/ correct count) 'float) #\newline)))

This creates y's copy every time otherwise y-labels' value is not updated.

I guess this is due to accessing the wrong facets or something like that. hmm