How much is a char in a string

[altenbach]

Maybe you can increase the lenght of the string subset by (m-1) while keeping the index positions the same (where "m" is the lenght of the matched string). 😉

[ouadji]

Maybe you can increase the lenght of the string subset by (m-1)

while keeping the index positions the same (where "m" is the lenght of the matched string)

I do not understand what you mean

"increase the lenght of the string subset by (m-1), while keeping the index positions the same"

where do that ? in the code of "Count or parralel Count" ?

in any cases, this will not prevent to split the main string in the middle of a substring

I search and I count the substrint "ABCD" ...

main string : zzzzzzzzzzABCDzzzzzzzzzzzz

split : zzzzzzzzzzAB | CDzzzzzzzzzzzz  (ABCD will not be found)

sorry, i don't understand your comment  (Maybe you can increase...)

[altenbach]

You simply make each subset longer so there is a small overlap. If the search string is 4 characters, make the subset 3 characters longer (characters shown in red). Now you get exactly one match (underlined), no matter where the cut is (either in the first or in the second substring).

For example like this:

Here are some examples.

zzzzzzzzzzzz|ABC               

            |ABCDzzzzzzzzzzzzzz

zzzzzzzzzzzzA|BCD

             |BCDzzzzzzzzzzzzzz

zzzzzzzzzzzzAB|CDz

              |CDzzzzzzzzzzzzzz

zzzzzzzzzzzzABC|Dzz            

               |Dzzzzzzzzzzzzzz

zzzzzzzzzzzzABCD|zzz            

                |zzzzzzzzzzzzzzz

[ouadji]

ok, understood.

an overlap of (m-1) ... yes, of course, obviously ...smart idea !

thank you altenbach

[ouadji]

Q6600 - 4 core - 2.6Ghz

main string : 50e6 char

count the number of "abc"

4 core => N/C=4

N=4    C=disable  64ms   cpu 67%   0

N=4    C=1        64ms   cpu 67%  -0

N=8    C=2        62ms   cpu 64%  -2

N=16   C=4        60ms   cpu 64%  -2

N=32   C=8        53ms   cpu 60%  -7 max delta   

N=64   C=16       48ms   cpu 60%  -5

N=128  C=32       44ms   cpu 55%  -4

N=256  C=64       43ms   cpu 53%  -1 max speed

N=512  C=128      43ms   cpu 53%  -0

[ouadji]

by cons, with your "Count_Parallel" code, the speed  does not change
if I change "reshape array / dimesion size" and  "For Loop / C" ... it's curious.

[altenbach]

---

@ouadji wrote:

by cons, with your "Count_Parallel" code, the speed  does not change
if I change "reshape array / dimesion size" and  "For Loop / C" ... it's curious.

---

This post does not provide sufficient information to be useful.