Re: map-par slower than map

[Damien Mattei]

https://github.com/damien-mattei/library-FunctProg/blob/master/guile/logiki%2B.scm#L1674

i commited the current version of code here with all files but it is
huge.... :-/

On Wed, Oct 12, 2022 at 10:20 PM Damien Mattei <damien.mattei@gmail.com>
wrote:

> Mutex? i do not think code has situation where dead lock could happen, it
> is a code about minimalising logic expressions, it uses minterms , minterms
> set is a set of minterms :like this:
>
> example:
> ((1 1 0) (1 1 1)) will be unified : (1 1 x)
> because 0 and 1 are replaced by x
> the minterms-set could have thousands of pair (mathematic not lisp)
> minterms to unify
> if there is more than one x as result there is no need to continue so i
> escape with a continuation:
>
> minterms-set =
> {
> ((1 0 1 0) (1 1 1 0))
> ((1 0 1 0) (1 1 0 1))
> ((1 0 1 0) (1 0 1 1))
> ((1 0 1 0) (0 1 1 1))
> ((0 1 1 0) (1 1 1 0))
> ((0 1 1 0) (1 1 0 1))
> ((0 1 1 0) (1 0 1 1))
> ((0 1 1 0) (0 1 1 1))
> ((0 1 0 1) (1 1 1 0))
> ((0 1 0 1) (1 1 0 1))
> ((0 1 0 1) (1 0 1 1))
> ((0 1 0 1) (0 1 1 1))
> ((0 0 1 1) (1 1 1 0))
> ((0 0 1 1) (1 1 0 1))
> ((0 0 1 1) (1 0 1 1))
> ((0 0 1 1) (0 1 1 1))
> }
>
> replace { } by () to have the list, other example at another level :
>
> minterms-set =
> {
> ((0 x 1 1) (x 1 1 1))
> ((0 x 1 1) (1 x 1 1))
> ((0 x 1 1) (1 1 x 1))
> ((0 x 1 1) (1 1 1 x))
> ((x 0 1 1) (x 1 1 1))
> ((x 0 1 1) (1 x 1 1))
> ((x 0 1 1) (1 1 x 1))
> ((x 0 1 1) (1 1 1 x))
> ((0 1 x 1) (x 1 1 1))
> ((0 1 x 1) (1 x 1 1))
> ((0 1 x 1) (1 1 x 1))
> ((0 1 x 1) (1 1 1 x))
> ((x 1 0 1) (x 1 1 1))
> ((x 1 0 1) (1 x 1 1))
> ((x 1 0 1) (1 1 x 1))
> ((x 1 0 1) (1 1 1 x))
> ((0 1 1 x) (x 1 1 1))
> ((0 1 1 x) (1 x 1 1))
> ((0 1 1 x) (1 1 x 1))
> ((0 1 1 x) (1 1 1 x))
> ((x 1 1 0) (x 1 1 1))
> ((x 1 1 0) (1 x 1 1))
> ((x 1 1 0) (1 1 x 1))
> ((x 1 1 0) (1 1 1 x))
> ((1 0 1 x) (x 1 1 1))
> ((1 0 1 x) (1 x 1 1))
> ((1 0 1 x) (1 1 x 1))
> ((1 0 1 x) (1 1 1 x))
> ((1 x 1 0) (x 1 1 1))
> ((1 x 1 0) (1 x 1 1))
> ((1 x 1 0) (1 1 x 1))
> ((1 x 1 0) (1 1 1 x))
> }
>
> here we see some minterms are already unified
>
>  it is not easy to read even by me because i wrote the code many years ago
> and is split in many files, but here it is:
>
> (par-map function-unify-minterms-list minterms-set)
>
> {function-unify-minterms-list <+ (λ (L) (apply
> function-unify-two-minterms-and-tag L))}
>
> (define (unify-two-minterms mt1 mt2)
>   (function-map-with-escaping-by-kontinuation2
>  (macro-function-compare-2-bits-with-continuation) mt1 mt2))
>
> ;; (function-map-with-escaping-by-kontinuation2
> (macro-function-compare-2-bits-with-continuation)   '(1 1 0 1 0 1 1 0) '(1
> 1 0 1 1 1 1 1))
>
> ;; list1 = (1 1 0 1 0 1 1 0)
> ;; more-lists = ((1 1 0 1 1 1 1 1))
> ;; lists = ((1 1 0 1 0 1 1 0) (1 1 0 1 1 1 1 1))
> ;; clozure = #<procedure:...gos-DrRacket.scm:195:11>
>
> ;; #f
> ;;
> ;;  (function-map-with-escaping-by-kontinuation2
> (macro-function-compare-2-bits-with-continuation)    '(1 1 0 1 0 1 1 0) '(1
> 1 0 1 1 1 1 0))
>
> ;; list1 = (1 1 0 1 0 1 1 0)
> ;; more-lists = ((1 1 0 1 1 1 1 0))
> ;; lists = ((1 1 0 1 0 1 1 0) (1 1 0 1 1 1 1 0))
> ;; clozure = #<procedure:...gos-DrRacket.scm:195:11>
>
> ;; '(1 1 0 1 x 1 1 0)
> (define (function-map-with-escaping-by-kontinuation2 clozure list1 .
> more-lists)
>   (call/cc (lambda (kontinuation)
>     (let ((lists (cons list1 more-lists))
>   (funct-continu ;; this function have the kontinuation in his environment
>    (lambda (arg1 . more-args)
>      (let ((args (cons arg1 more-args)))
> (apply clozure kontinuation args))))) ;; a tester: (apply clozure (cons
> conti args))
>
>          ;; (newline)
>          ;; (dv list1)
>          ;; (dv more-lists)
>          ;; (dv lists)
>  ;; (dv clozure)
>          ;; (newline)
>
>       (apply map funct-continu lists)))))
>
> (define-syntax macro-function-compare-2-bits-with-continuation ;;
> continuation version of macro-compare-2-bits
>   ;; i need a macro because of external function to the clozure
>   (syntax-rules ()
>     ((_) (let ((cnt 0)) ;; counter
>   (lambda (continuation b1 b2) (if (equal? b1 b2)
>  b1
>  (begin
>    (set! cnt (add1 cnt)) ;; we leave with continuation in case cpt > 1, we
> can have used a flag too instead of a counter
>    (when (> cnt 1) (continuation #f)) ;; escaping with the continuation
>    'x))))))) ;; return x in case of (b1,b2) = (O,1) or (1,0)
>
> what could have caused mutex if in the latter definition above (let ((cnt
> 0)) ;; counter was defined at top level and shared by all threads!!! yes
> there could have be some mutex  but this is not the case, i think even all
> function are pure so why is it more slow with // than without?
> Damien
>
> On Wed, Oct 12, 2022 at 8:45 PM Maxime Devos <maximedevos@telenet.be>
> wrote:
>
>> On 12-10-2022 19:19, Damien Mattei wrote:
>> > Hello,
>> > all is in the title, i test on a approximately 30000 element list , i
>> got
>> > 9s with map and 3min 30s with par-map on exactly the same piece of
>> code!?
>> >
>>  > [...]
>>  >
>> > translated from Scheme+ to Scheme:
>> > (define unified-minterms-set-1 (map function-unify-minterms-list
>> > minterms-set)) ;;(par-map function-unify-minterms-list minterms-set))
>>
>> The definition of 'function-unify-minterms-list' and 'minterms-set' is
>> missing.  Without a test case, we can only speculate what's going on.
>> (E.g., maybe it grabs a mutex).
>>
>> Greetings,
>> Maxime.
>>
>