Hello,

I was wondering whether optimization can help grid-map's performance. (But I really have not done
much optimizing). So, I timed the following two functions which map `sin' over a really large grid:

(in-package :grid)

(defun optimized (arg)
(grid:map-grid :source arg
        :element-function
        #'(lambda (arg)
        (declare
        (optimize (speed 3) (safety 0) (debug 0))
        (double-float arg))
        (the double-float (sin arg))))
(values))

(defun unoptimized (arg)
(grid:map-grid :source arg
        :element-function
        #'(lambda (arg)
        (sin arg)))
(values))

(progn
(defvar *arg* nil)
(setf *arg* (grid:make-grid '((foreign-array 300000) double-float)
                  :initial-element 1d0))
nil)

On 64bit linux & SBCL, compilation of the optimized routine generate the following notes
that I don't understand:

; note: unable to avoid inline argument range check
; because the argument range (DOUBLE-FLOAT) was not within 2^63

;     #'(LAMBDA (GRID::ARG)
;         (DECLARE (OPTIMIZE (SPEED 3) (SAFETY 0) (DEBUG 0))
;                  (DOUBLE-FLOAT GRID::ARG))
;         (THE DOUBLE-FLOAT (SIN GRID::ARG)))
;
; note: doing float to pointer coercion (cost 13) to "<return value>"

Timing both routines gives very similar results:

GRID> (time (unoptimized *arg*))
Evaluation took:
0.112 seconds of real time
0.111983 seconds of total run time (0.110983 user, 0.001000 system)
[ Run times consist of 0.004 seconds GC time, and 0.108 seconds non-GC time. ]
100.00% CPU
335,890,827 processor cycles
19,202,048 bytes consed

GRID> (time (optimized *arg*))
Evaluation took:
0.113 seconds of real time
0.112983 seconds of total run time (0.111983 user, 0.001000 system)
[ Run times consist of 0.003 seconds GC time, and 0.110 seconds non-GC time. ]
100.00% CPU
337,194,558 processor cycles
19,202,032 bytes consed

Any ideas how to properly optimize the code?

Thanks,

Mirko