caused by: (array->bytevector (512vec simustate))
*** Error in `/nix/store/6abivsnvv8b7mxldxzyppg36sg9krifx-chicken-4.12.0/bin/csi': double free or corruption (!prev): 0x000000000159f780 ***

(define (array->bytevector arr)
  (define w (dim-size arr 0))
  (define h (dim-size arr 1))

  (define flat (gu:make-bytevector (* w h) 0 #t))
  (do-for j (0 h)
          (do-for i (0 w)
                  (gu:bytevector-u8-set! flat (inc (to-linear-idx w (cons i j))) (array-ref arr i j))
                  ))
  flat)

(define (512vec arri)
  (define w (dim-size arri 0))
  (define h (dim-size arri 1))
  (define powt 32)
  (define exp (dec (- (/ powt 2) (/ (dec w) 2))))
  (define arr (array-pad-asym (expand-simu exp arri)))
  (do-for i (0 (* powt powt))
          (match-let ([(k . j) (from-linear-idx powt i)])
            (array-set! arr k j
                        (cond ((or (>= k h) (>= j w)) 0)
                              ((= (array-ref arri k j) 0) 0)
                              (else (array-ref arri k j))))
          ))
  (array-print arr)
  arr
  )

(define (512vec arri)
  (define w (dim-size arri 0))
  (define h (dim-size arri 1))
  (define powt 32)
  (define exp (dec (- (/ powt 2) (/ (dec w) 2))))
  (define arr (array-pad-asym (expand-simu exp arri)))
  
  (array-print arr)
  arr
  )