Dima
this is not really c++ topic
Anonymous
I have a struct like this
struct a
{
float* array1, array2;
}
a myarray[512];
I malloc() array1 and array2 per element to 256 each making each element exactly 512 all cache aligned
I made a second struct
struct a
{
float array1[512];
float array2[512];
}
a myarray[512];
they both perform at the same speed, I assumed using malloc() on array elements would have made a less efficient system but, seems not.
Anonymous
Infact I am finding it very hard to hit any cache penalty intentionally, I am compiling with clang
Anonymous
clang version 9.0.0-2 (tags/RELEASE_900/final)
Target: x86_64-pc-linux-gnu
Thread model: posix
Anonymous
I only ever iterate 0 to 512 sequentially, so I assumed having the memory in one big block array would be more efficient
as I assume defining a block array of 512 x2 pointers (4 bytes per pointer so 8x512 bytes in the lookup array) and then malloc() is like having a lookup table array struct a[512] to what is then a big block array of 1024 floats (4 bytes x 1024) per struct 512 times in a big sequential array
Anonymous
either way I saw no change in time to iterate either solutions.
Anonymous
But I can iterate a memory mapped file a lot faster lol, as long as im just doing a memcmp on each element
like 10 - 20 times faster than iterating a much smaller array of floats and doing some basic arithmetic
Anonymous
i guess there is some latency of the cpu accessing the fpu, as where in a standard byte comparison iteration it's all on the main cpu ?
Anonymous
hello who understans french ?
Natarajan
Anonymous
anyway i have a project i dont know how to do it can someone help me (this is my first time in telegrame )
Talula
anyway i have a project i dont know how to do it can someone help me (this is my first time in telegrame )
What kind of project? If it's a very large one, we could try give you tips.
Anonymous
okey thank you, i went to google translate this is it :
Anonymous
We wanted to computerize the schooling of the computer science department, knowing that there are 6 semesters
License and 4 semesters Master, such as:
─ Each semester contains challenging modules.
─ Each module contains: CC score, exam score and Average.
─
Providing a program in C allows you to manage an endless list of students. Each student is
represented by: a number, Name, First name, Date of birth, date of registration, modules with
their notes ...
Also this program offers the following services (functions and procedures):
─ Register a student.
─ Enter a student's grades.
─ Calculate the average of a student.
─ Display the students whose mean> = 10
─ Display% of students whose average> = 10 (admitted)
─ Display% of students with average <10 (postponed)
─ Displays the number of registered students
Note: You must use pointers, structures and lists.
Anonymous
i am so new to chapter lists and i dont know how to use them in this project and i dont have much time please help me : give me tips or anything you can
Anonymous
yes it is a school project
Anonymous
okey i will thank you
Talula
i am so new to chapter lists and i dont know how to use them in this project and i dont have much time please help me : give me tips or anything you can
What tips? I mean you have to start somewhere and if you get stuck we could help you, what you wanna do? Want us to make the whole software for you?
Anonymous
no, not like that , well i searched in youtube and google .... i read about it i tried , can i send you what i wrote in c++ till now and gide me like give me notes if i am in the right way or i should change my methode ?
Anonymous
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
typedef struct {
char nom[30];//surname
char prenom[30];//name
char Date_naissance[30];//birthday
char Date_inss[30];//day of inscription
float moyenne;
} etudiant ;
typedef struct cellule cellule ;
typedef cellule* liste ;
struct cellule {
etudiant data ;
cellule * next ;
};
cellule* newetudiant (etudiant e )
{
cellule * b ;
b=(cellule*)malloc(sizeof(cellule));
b->data=e;
b->next=NULL;
return b ;
}
void ajouteraudebut (liste* debut, etudiant e )
{
cellule * b ;
b=newetudiant(e);
b->next=*debut;
*debut=b;
}
void ajouteralafin(liste* debut, etudiant e)
{
cellule * b , *temp ;
b=newetudiant (e);
if(*debut == NULL)
*debut=b;
else {
temp =*debut ;
while(temp->next !=NULL)
temp=temp->next ;
temp->next=b;
}
}
void ajouteretudiant(liste* debut ,etudiant e )
{
if(e.moyenne<=10)
ajouteraudebut(debut,e);
else
ajouteralafin(debut,e);
}
void afficher (liste debut )
{
cellule * temp ;
if(debut == NULL)
printf("la liste est vide ");
else
{
temp = debut ;
while(temp!=NULL)
{
printf("%s \t %f -> ",temp->data.nom,temp->data.moyenne);
temp =temp->next ;
}
}
}
int main ()
{
liste l1=NULL;
etudiant e;
int chx;
do {
printf("nom : ");
scanf("%s",&e.nom);
printf("prenom : ");
scanf("%s",&e.prenom);
printf("Date naiss : ");
scanf("%s",&e.Date_naiss);
printf("Date inss : ");
scanf("%s",&e.Date_inss);
printf("moyenne : ");
scanf("%f",&e.moyenne);
ajouteretudiant(&l1,e);
printf("un autre etudiant 0 si non : ");
scanf("%d",&chx);
}while(chx!=0);
afficher(l1);
return 0 ;
}
Anonymous
i made this work using a programme that takes students who have more than 10 and put them in the end of list and take who has less then 10 and put them in the head
Anonymous
i know its is not what i have to do but should i continue or stop ? or ? (sorry for my bad english )
Talula
i know its is not what i have to do but should i continue or stop ? or ? (sorry for my bad english )
Yeah but I would love to know where you're stuck... I am not going to do your task for you.
Anonymous
i understand you are right , i will try harder and come back with better questions
Anonymous
and i just wanted oriontation to see if i am fine or i am totally wrong
Parikshit
Is there anything called access modifier in cpp?
Andrew
Amir
it's basically defined in OOP object oriented programming
Parikshit
But what is that?
Amir
What is your query then?
Amir
Access modifier are used to give particular access and modify levels
Parikshit
I know access specifier but didn't know about modifier
Amir
like private public protected
Parikshit
Access modifier are used to give particular access and modify levels
In inheritance? Or just in class?
Hadaward 'Solly'
he just wants to know the reserved words for C++ if there's any
Amir
obviously in both of them. there are rules for subclasses and classes
Parikshit
Okay, thanks
Anonymous
I found out my memory speed is 19.1 GB/s
Anonymous
Anonymous
This is my bottleneck as I am trying to push 36 GB in one pass, and a pass takes 4-5 seconds
Anonymous
two threads can still do 5-6 seconds
Anonymous
but after that the ram bus is truly exhausted
Anonymous
and the processes just start to take longer ofc
Dima
cool
Anonymous
what can I do, just deal with it ? I am trying to compute a neural network, I looked at the RTX cards and they have only 14 GB/s !!!!
Anonymous
Unles I get a EPYC with 8 ram channels and 16 slots
Anonymous
but even then that is only 2100 MHz under full load with the mobo's im looking at
Anonymous
I need more, and i need it faster, is this all modern technology is going to give me ?! 20 GB/s !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
25 GB/s at a push
Anonymous
PATHETIC
Ludovic 'Archivist'
the rules dont appear as pinned to me. Anyone knows why?
Because you closed the pinned message at some point
Hadaward 'Solly'
heck
Anonymous
WOW WTF IT WAS A LINK TO THE RULES PIN
Dima
lol
Dima
darwin theory
Anonymous
LOL FFS
Anonymous
NOOOOOOOOooooooooooooooooooo
Hadaward 'Solly'
yeah i got banned in the python groups for a similar reason
Hadaward 'Solly'
i forwarded one of the admin messages bellow rules cuz it had the reference material someone asked haha
Hadaward 'Solly'
it had telegram ids... 😐
Anonymous
i forwarded one of the admin messages bellow rules cuz it had the reference material someone asked haha
lmfao could be a good troll tbh, tricking people to forward stuff you know will get them banned
Hadaward 'Solly'
i could've used the commands but i didnt learn them quick enough
Hadaward 'Solly'
nah, people ask for references all the time in language groups
Dima
#ot
Hadaward 'Solly'
i'm not even mad, just sad heh
Dima
/ban 1288595836
Hadaward 'Solly'
nice reference. Btw Dima, could you edit the rules message to include the offtopic group link in the bottom?
Dima
/unban 1397820592
Anonymous
ty
Wendy
Hello am new hear
Dima
lol