C Malloc 3D array
I am trying to run the code below, but I receive an error (during the for loop). It seems that my "3D array" is defined (for i, j, k max) as c[nL_thread][nL][nL] while I am trying to set the indices as c[nL][nL][nL_thread], hence the error.
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<omp.h>
#include<mpi.h>
double ***alloc3(int x, int y, int z){
int i, j;
double *p = (double *) malloc(x*y*z*sizeof(double));
double ***array = (double ***) malloc(x*sizeof(double **));
for (i=0; i<x; i++){
array[i] = (double **) malloc(y*sizeof(double *));
for (j=0; j<y; j++){
int idx = x*j + x*y*i;
array[i][j] = &p[idx];}}
return array;
}
int main(int argc, char *argv){
MPI_Init(&argc, &argv);
int i, j, k;
int nL;
int nL_thread;
double ***c;
int nbr, rank;
MPI_Comm_size(MPI_COMM_WORLD, &nbr);
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
nL = 10;
nL_thread = 4;
c = alloc3(nL+1, nL+1, nL_thread+1);
for(k=0; k<=nL_thread; k++){
for(j=0; j<=nL; j++){
for(i=0; i<=nL; i++){
c[i][j][k] = 0;}}}
MPI_Finalize();
}
Thank you in advance for your help.
c
asked Nov 18 '18 at 1:39
IzyrIzyr
32
add a comment |
I am trying to run the code below, but I receive an error (during the for loop). It seems that my "3D array" is defined (for i, j, k max) as c[nL_thread][nL][nL] while I am trying to set the indices as c[nL][nL][nL_thread], hence the error.
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<omp.h>
#include<mpi.h>
double ***alloc3(int x, int y, int z){
int i, j;
double *p = (double *) malloc(x*y*z*sizeof(double));
double ***array = (double ***) malloc(x*sizeof(double **));
for (i=0; i<x; i++){
array[i] = (double **) malloc(y*sizeof(double *));
for (j=0; j<y; j++){
int idx = x*j + x*y*i;
array[i][j] = &p[idx];}}
return array;
}
int main(int argc, char *argv){
MPI_Init(&argc, &argv);
int i, j, k;
int nL;
int nL_thread;
double ***c;
int nbr, rank;
MPI_Comm_size(MPI_COMM_WORLD, &nbr);
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
nL = 10;
nL_thread = 4;
c = alloc3(nL+1, nL+1, nL_thread+1);
for(k=0; k<=nL_thread; k++){
for(j=0; j<=nL; j++){
for(i=0; i<=nL; i++){
c[i][j][k] = 0;}}}
MPI_Finalize();
}
Thank you in advance for your help.
c
asked Nov 18 '18 at 1:39
IzyrIzyr
32
Note:x*y*zinx*y*z*sizeof(double)can overflowintmath.sizeof(double)*x*y*zhas the advantage of usingsize_tmath, certainly wider thanint. Important if your x,y,z values are large.
– chux
Nov 18 '18 at 1:47
"I receive an error (during the for loop)" --> Please describe the error indication and provide any error message.
– chux
Nov 18 '18 at 1:48
int idx = x*j + x*y*i;should beint idx = z*j + y*z*i;?
– Osiris
Nov 18 '18 at 2:11
add a comment |
I am trying to run the code below, but I receive an error (during the for loop). It seems that my "3D array" is defined (for i, j, k max) as c[nL_thread][nL][nL] while I am trying to set the indices as c[nL][nL][nL_thread], hence the error.
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<omp.h>
#include<mpi.h>
double ***alloc3(int x, int y, int z){
int i, j;
double *p = (double *) malloc(x*y*z*sizeof(double));
double ***array = (double ***) malloc(x*sizeof(double **));
for (i=0; i<x; i++){
array[i] = (double **) malloc(y*sizeof(double *));
for (j=0; j<y; j++){
int idx = x*j + x*y*i;
array[i][j] = &p[idx];}}
return array;
}
int main(int argc, char *argv){
MPI_Init(&argc, &argv);
int i, j, k;
int nL;
int nL_thread;
double ***c;
int nbr, rank;
MPI_Comm_size(MPI_COMM_WORLD, &nbr);
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
nL = 10;
nL_thread = 4;
c = alloc3(nL+1, nL+1, nL_thread+1);
for(k=0; k<=nL_thread; k++){
for(j=0; j<=nL; j++){
for(i=0; i<=nL; i++){
c[i][j][k] = 0;}}}
MPI_Finalize();
}
Thank you in advance for your help.
c
asked Nov 18 '18 at 1:39
IzyrIzyr
32
I am trying to run the code below, but I receive an error (during the for loop). It seems that my "3D array" is defined (for i, j, k max) as c[nL_thread][nL][nL] while I am trying to set the indices as c[nL][nL][nL_thread], hence the error.
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<omp.h>
#include<mpi.h>
double ***alloc3(int x, int y, int z){
int i, j;
double *p = (double *) malloc(x*y*z*sizeof(double));
double ***array = (double ***) malloc(x*sizeof(double **));
for (i=0; i<x; i++){
array[i] = (double **) malloc(y*sizeof(double *));
for (j=0; j<y; j++){
int idx = x*j + x*y*i;
array[i][j] = &p[idx];}}
return array;
}
int main(int argc, char *argv){
MPI_Init(&argc, &argv);
int i, j, k;
int nL;
int nL_thread;
double ***c;
int nbr, rank;
MPI_Comm_size(MPI_COMM_WORLD, &nbr);
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
nL = 10;
nL_thread = 4;
c = alloc3(nL+1, nL+1, nL_thread+1);
for(k=0; k<=nL_thread; k++){
for(j=0; j<=nL; j++){
for(i=0; i<=nL; i++){
c[i][j][k] = 0;}}}
MPI_Finalize();
}
Thank you in advance for your help.
c
c
asked Nov 18 '18 at 1:39
IzyrIzyr
32
asked Nov 18 '18 at 1:39
IzyrIzyr
32
edited Nov 18 '18 at 1:44
Izyr
asked Nov 18 '18 at 1:39
IzyrIzyr
32
asked Nov 18 '18 at 1:39
IzyrIzyr
32
asked Nov 18 '18 at 1:39
IzyrIzyr
32
32
Note:x*y*zinx*y*z*sizeof(double)can overflowintmath.sizeof(double)*x*y*zhas the advantage of usingsize_tmath, certainly wider thanint. Important if your x,y,z values are large.
– chux
Nov 18 '18 at 1:47
"I receive an error (during the for loop)" --> Please describe the error indication and provide any error message.
– chux
Nov 18 '18 at 1:48
int idx = x*j + x*y*i;should beint idx = z*j + y*z*i;?
– Osiris
Nov 18 '18 at 2:11
add a comment |
Note:x*y*zinx*y*z*sizeof(double)can overflowintmath.sizeof(double)*x*y*zhas the advantage of usingsize_tmath, certainly wider thanint. Important if your x,y,z values are large.
– chux
Nov 18 '18 at 1:47
"I receive an error (during the for loop)" --> Please describe the error indication and provide any error message.
– chux
Nov 18 '18 at 1:48
int idx = x*j + x*y*i;should beint idx = z*j + y*z*i;?
– Osiris
Nov 18 '18 at 2:11
Note:
x*y*z in x*y*z*sizeof(double) can overflow int math. sizeof(double)*x*y*z has the advantage of using size_t math, certainly wider than int. Important if your x,y,z values are large.– chux
Nov 18 '18 at 1:47
Note:
x*y*z in x*y*z*sizeof(double) can overflow int math. sizeof(double)*x*y*z has the advantage of using size_t math, certainly wider than int. Important if your x,y,z values are large.– chux
Nov 18 '18 at 1:47
"I receive an error (during the for loop)" --> Please describe the error indication and provide any error message.
– chux
Nov 18 '18 at 1:48
"I receive an error (during the for loop)" --> Please describe the error indication and provide any error message.
– chux
Nov 18 '18 at 1:48
int idx = x*j + x*y*i; should be int idx = z*j + y*z*i;?– Osiris
Nov 18 '18 at 2:11
int idx = x*j + x*y*i; should be int idx = z*j + y*z*i;?– Osiris
Nov 18 '18 at 2:11
add a comment |
1 Answer
1
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oldest
votes
You have a problem in your allocation function. The calculation of the offset idx is wrong:
int idx = x*j + x*y*i;
should be
int idx = z*j + y*z*i;
Note that array[i][j+1] should point to z elements after array[i][j], and array[i+1][j] should point to y*z elements after array[i][j]. That is the reason why the sizes seem switched (but maybe also leads to out of bounds access).
answered Nov 18 '18 at 2:16
OsirisOsiris
2,568416
add a comment |
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1 Answer
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1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
You have a problem in your allocation function. The calculation of the offset idx is wrong:
int idx = x*j + x*y*i;
should be
int idx = z*j + y*z*i;
Note that array[i][j+1] should point to z elements after array[i][j], and array[i+1][j] should point to y*z elements after array[i][j]. That is the reason why the sizes seem switched (but maybe also leads to out of bounds access).
answered Nov 18 '18 at 2:16
OsirisOsiris
2,568416
add a comment |
You have a problem in your allocation function. The calculation of the offset idx is wrong:
int idx = x*j + x*y*i;
should be
int idx = z*j + y*z*i;
Note that array[i][j+1] should point to z elements after array[i][j], and array[i+1][j] should point to y*z elements after array[i][j]. That is the reason why the sizes seem switched (but maybe also leads to out of bounds access).
answered Nov 18 '18 at 2:16
OsirisOsiris
2,568416
add a comment |
You have a problem in your allocation function. The calculation of the offset idx is wrong:
int idx = x*j + x*y*i;
should be
int idx = z*j + y*z*i;
Note that array[i][j+1] should point to z elements after array[i][j], and array[i+1][j] should point to y*z elements after array[i][j]. That is the reason why the sizes seem switched (but maybe also leads to out of bounds access).
answered Nov 18 '18 at 2:16
OsirisOsiris
2,568416
You have a problem in your allocation function. The calculation of the offset idx is wrong:
int idx = x*j + x*y*i;
should be
int idx = z*j + y*z*i;
Note that array[i][j+1] should point to z elements after array[i][j], and array[i+1][j] should point to y*z elements after array[i][j]. That is the reason why the sizes seem switched (but maybe also leads to out of bounds access).
answered Nov 18 '18 at 2:16
OsirisOsiris
2,568416
edited Nov 18 '18 at 2:24
answered Nov 18 '18 at 2:16
OsirisOsiris
2,568416
answered Nov 18 '18 at 2:16
OsirisOsiris
2,568416
answered Nov 18 '18 at 2:16
OsirisOsiris
2,568416
2,568416
add a comment |
add a comment |
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Note:
x*y*zinx*y*z*sizeof(double)can overflowintmath.sizeof(double)*x*y*zhas the advantage of usingsize_tmath, certainly wider thanint. Important if your x,y,z values are large.– chux
Nov 18 '18 at 1:47
"I receive an error (during the for loop)" --> Please describe the error indication and provide any error message.
– chux
Nov 18 '18 at 1:48
int idx = x*j + x*y*i;should beint idx = z*j + y*z*i;?– Osiris
Nov 18 '18 at 2:11