{"id":3762,"date":"2015-06-29T21:25:35","date_gmt":"2015-06-29T12:25:35","guid":{"rendered":"http:\/\/pchero21.com\/?p=3762"},"modified":"2015-06-29T21:26:02","modified_gmt":"2015-06-29T12:26:02","slug":"memory-indexing-differences","status":"publish","type":"post","link":"http:\/\/pchero21.com\/?p=3762","title":{"rendered":"memory indexing differences"},"content":{"rendered":"

for \uad6c\ubb38 \uc0ac\uc6a9\uc2dc, \uc778\ub371\uc2f1\ud558\ub294 order \uc5d0 \ub530\ub77c, \uc2e4\ud589\uc2dc\uac04\uc5d0 \ucc28\uc774\uac00 \ubc1c\uc0dd\ud55c\ub2e4\ub294 \uae00\uc744 \ubcf4\uc558\ub2e4(\ucc38\uc870: http:\/\/process3.blog.me\/20030421397)<\/p>\n

\uc815\ub9d0\ub85c \uadf8\ub7f4\uae4c? \ud55c\ubc88 \ud655\uc778\ud574 \ubcf4\uc558\ub2e4. \uacb0\ub860\uc740? \ud655\uc2e4\ud55c \ucc28\uc774\uac00 \uc788\uc5c8\ub2e4.<\/p>\n

\uc774\uc720\ub97c \ud655\uc778\ud574\ubcf4\ub2c8, \uba54\ubaa8\ub9ac \uce90\uc2dc\uc640 \uad00\ub828\ub41c \ub0b4\uc6a9\uc774\uc5c8\ub2e4.<\/p>\n

 <\/p>\n

\n
— Program 1<\/div>\n
#include <stdio.h><\/div>\n
<\/div>\n
#define MAX_CNT 100<\/div>\n
<\/div>\n
int main(int argc, char** argv)<\/div>\n
{<\/div>\n
\u00a0 \u00a0 int i, j, k;<\/div>\n
\u00a0 \u00a0 int test_data[MAX_CNT][MAX_CNT][MAX_CNT];<\/div>\n
<\/div>\n
\u00a0 \u00a0 for(i = 0; i < MAX_CNT; i++)<\/div>\n
\u00a0 \u00a0 {<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 for(j = 0; j < MAX_CNT; j++)<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 {<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 for(k = 0; k < MAX_CNT; k++)<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 {<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 test_data[i][j][k] = 100;<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 }<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 }<\/div>\n
\u00a0 \u00a0 }<\/div>\n
<\/div>\n
\u00a0 \u00a0 return 0;<\/div>\n
}<\/div>\n
<\/div>\n
Result<\/div>\n
$ time .\/main<\/div>\n
<\/div>\n
real\u00a0 \u00a0 0m0.008s<\/div>\n
user\u00a0 \u00a0 0m0.004s<\/div>\n
sys \u00a0 \u00a0 0m0.004s<\/div>\n
<\/div>\n
<\/div>\n
— Program 2<\/div>\n
#include <stdio.h><\/div>\n
<\/div>\n
#define MAX_CNT 100<\/div>\n
<\/div>\n
<\/div>\n
int main(int argc, char** argv)<\/div>\n
{<\/div>\n
\u00a0 \u00a0 int i, j, k;<\/div>\n
\u00a0 \u00a0 int test_data[MAX_CNT][MAX_CNT][MAX_CNT];<\/div>\n
<\/div>\n
\u00a0 \u00a0 for(i = 0; i < MAX_CNT; i++)<\/div>\n
\u00a0 \u00a0 {<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 for(j = 0; j < MAX_CNT; j++)<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 {<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 for(k = 0; k < MAX_CNT; k++)<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 {<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 test_data[k][j][i] = 100;<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 }<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 }<\/div>\n
\u00a0 \u00a0 }<\/div>\n
<\/div>\n
\u00a0 \u00a0 return 0;<\/div>\n
}<\/div>\n
<\/div>\n
$ time .\/main<\/div>\n
<\/div>\n
real\u00a0 \u00a0 0m0.017s<\/div>\n
user\u00a0 \u00a0 0m0.013s<\/div>\n

sys \u00a0 \u00a0 0m0.004s<\/p><\/blockquote>\n

 <\/p>\n

\ud799 \uc601\uc5ed \uc0ac\uc6a9\uc2dc, \ubcf4\ub2e4 \ub354 \ud070 \ucc28\uc774\ub97c \ud655\uc778\ud560 \uc218 \uc788\ub2e4.<\/p>\n

\n
— Program 1<\/div>\n
#include <stdio.h><\/div>\n
#include <stdlib.h><\/div>\n
<\/div>\n
#define MAX_CNT 500<\/div>\n
<\/div>\n
<\/div>\n
int main(int argc, char** argv)<\/div>\n
{<\/div>\n
\u00a0 \u00a0 int i, j, k;<\/div>\n
\/\/ \u00a0 \u00a0int test_data[MAX_CNT][MAX_CNT][MAX_CNT];<\/div>\n
\u00a0 \u00a0 int*** test_data;<\/div>\n
<\/div>\n
\u00a0 \u00a0 test_data = calloc(MAX_CNT, sizeof(int**));<\/div>\n
\u00a0 \u00a0 for(i = 0; i < MAX_CNT; i++)<\/div>\n
\u00a0 \u00a0 {<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 test_data[i] = calloc(MAX_CNT, sizeof(int*));<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 for(j = 0; j < MAX_CNT; j++)<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 {<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 test_data[i][j] = calloc(MAX_CNT, sizeof(int));<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 }<\/div>\n
\u00a0 \u00a0 }<\/div>\n
<\/div>\n
\u00a0 \u00a0 for(i = 0; i < MAX_CNT; i++)<\/div>\n
\u00a0 \u00a0 {<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 for(j = 0; j < MAX_CNT; j++)<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 {<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 for(k = 0; k < MAX_CNT; k++)<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 {<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 test_data[i][j][k] = 100;<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 }<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 }<\/div>\n
\u00a0 \u00a0 }<\/div>\n
<\/div>\n
\u00a0 \u00a0 return 0;<\/div>\n
}<\/div>\n
<\/div>\n
<\/div>\n
Result<\/div>\n
$ time .\/main<\/div>\n
<\/div>\n
real\u00a0 \u00a0 0m0.539s<\/div>\n
user\u00a0 \u00a0 0m0.367s<\/div>\n
sys \u00a0 \u00a0 0m0.172s<\/div>\n
<\/div>\n
<\/div>\n
— Program 2<\/div>\n
#include <stdio.h><\/div>\n
#include <stdlib.h><\/div>\n
<\/div>\n
#define MAX_CNT 500<\/div>\n
<\/div>\n
<\/div>\n
int main(int argc, char** argv)<\/div>\n
{<\/div>\n
\u00a0 \u00a0 int i, j, k;<\/div>\n
\/\/ \u00a0 \u00a0int test_data[MAX_CNT][MAX_CNT][MAX_CNT];<\/div>\n
\u00a0 \u00a0 int*** test_data;<\/div>\n
<\/div>\n
\u00a0 \u00a0 test_data = calloc(MAX_CNT, sizeof(int**));<\/div>\n
\u00a0 \u00a0 for(i = 0; i < MAX_CNT; i++)<\/div>\n
\u00a0 \u00a0 {<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 test_data[i] = calloc(MAX_CNT, sizeof(int*));<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 for(j = 0; j < MAX_CNT; j++)<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 {<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 test_data[i][j] = calloc(MAX_CNT, sizeof(int));<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 }<\/div>\n
\u00a0 \u00a0 }<\/div>\n
<\/div>\n
\u00a0 \u00a0 for(i = 0; i < MAX_CNT; i++)<\/div>\n
\u00a0 \u00a0 {<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 for(j = 0; j < MAX_CNT; j++)<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 {<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 for(k = 0; k < MAX_CNT; k++)<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 {<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 test_data[k][j][i] = 100;<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 }<\/div>\n
\u00a0 \u00a0 \u00a0 \u00a0 }<\/div>\n
\u00a0 \u00a0 }<\/div>\n
<\/div>\n
\u00a0 \u00a0 return 0;<\/div>\n
}<\/div>\n
<\/div>\n
Result<\/div>\n
$ time .\/main<\/div>\n
<\/div>\n
real\u00a0 \u00a0 0m5.344s<\/div>\n
user\u00a0 \u00a0 0m5.202s<\/div>\n
sys \u00a0 \u00a0 0m0.147s<\/div>\n<\/blockquote>\n","protected":false},"excerpt":{"rendered":"

for \uad6c\ubb38 \uc0ac\uc6a9\uc2dc, \uc778\ub371\uc2f1\ud558\ub294 order \uc5d0 \ub530\ub77c, \uc2e4\ud589\uc2dc\uac04\uc5d0 \ucc28\uc774\uac00 \ubc1c\uc0dd\ud55c\ub2e4\ub294 \uae00\uc744 \ubcf4\uc558\ub2e4(\ucc38\uc870: http:\/\/process3.blog.me\/20030421397) \uc815\ub9d0\ub85c \uadf8\ub7f4\uae4c? \ud55c\ubc88 \ud655\uc778\ud574 \ubcf4\uc558\ub2e4. \uacb0\ub860\uc740? \ud655\uc2e4\ud55c \ucc28\uc774\uac00 \uc788\uc5c8\ub2e4. \uc774\uc720\ub97c \ud655\uc778\ud574\ubcf4\ub2c8, \uba54\ubaa8\ub9ac \uce90\uc2dc\uc640 \uad00\ub828\ub41c \ub0b4\uc6a9\uc774\uc5c8\ub2e4.   — Program 1 #include <stdio.h> #define MAX_CNT 100 int main(int argc, … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[16],"tags":[128,917,961,949],"_links":{"self":[{"href":"http:\/\/pchero21.com\/index.php?rest_route=\/wp\/v2\/posts\/3762"}],"collection":[{"href":"http:\/\/pchero21.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/pchero21.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/pchero21.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/pchero21.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3762"}],"version-history":[{"count":3,"href":"http:\/\/pchero21.com\/index.php?rest_route=\/wp\/v2\/posts\/3762\/revisions"}],"predecessor-version":[{"id":3765,"href":"http:\/\/pchero21.com\/index.php?rest_route=\/wp\/v2\/posts\/3762\/revisions\/3765"}],"wp:attachment":[{"href":"http:\/\/pchero21.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3762"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/pchero21.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3762"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/pchero21.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3762"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}