anchor.diff:             (make-array (* n n) :initial-element 2)
              (make-array (* n n) :initial-element nil)))
   
  -(defun bench-pmm ()
  -  (let ((fns        '(mm pmm))
  +(defun bench-pmatrix-mul ()
  +  (let ((fns        '(matrix-mul pmatrix-mul))
           (trials     *trials*)
           (rehearsals *rehearsals*))
       (bench
  
positive.code:                           bench-psort
                            bench-preduce
                            bench-pfib
                            bench-pmm))
  
  (defparameter *sizes* '(10 100 500 1000 5000 10000 50000 100000 200000))
  
  
negative.code: 
         (compute-rows-between 0 (1- n)))))
  
  (define-mm matrix-mul defun let)
  (define-mm pmatrix-mul defpar plet)
  
  (defun run-mm (fn n)
    (funcall fn
  