Question

In C Language: Write a program to sum arrays row wise and column wise. Keep track of time to do each matrix each way. Export you times and matrix sizes to a csv file. Use excel to open you csv. Make a graph of your times versus matrix size.

Answer 1

Copy the code and run. Look at the screenshot for indentation. Comment incase of bugs/doubts.

CODE:

matiTime 2 3 #include <stdio.h» #1nclueestdlib.h> include <time.h> 5 int nain) t /set initial rowsice and colsize int co!size 16; e ta write to FILE* fp: fp fopen("tines,csw", while(rows1ze 1800) 18 /keep increasing rowsize till max 1imit is reached. Depends an avaitable RAM create array int arr[rowsize][colsize] ror [int j -9; j ros i ze ; j++) { //randomly ns sign values using rand runction 14 15 16 17 18 19 28 21 tor(int k=0; k< cols1ze; k++) { s rand( tine(e)) ; arri ] I IJ I = rand( ) ; clock t start, end; double tine_row; start clock forli t j -9; j < rows ize; İ ++) { //start and end store clock times /start clock 23 24. 25 26 27 28 29 35 31 32 //ite rate over all rows /stares sun long long int sun ; tor(int k: θ; k< colsize; kt+) { //ite rate over all columns sun arri][k]; //keep adding end - clack( tine row-((double) (end double time col startclock) stop clock start / CLOCKS PER SEC; /get time taken by adding row operation /repeat the sane. This time for column wise sum 34. 35 36 37 38 39 48 41 42 13 long long int sun ; sun+arr[k]lil; end clack( tine col-((double) (end start)) / CLOCKS PER SEC; fprintf(fp, "ริโ fAlfM,8d\n", timerow, tinecol, rowsize, rowsize2 colsize -2; colsize); //print to file - - increase row and cols1z 45 46 47 close(tp) return ;

#include <stdio.h>

#include <stdlib.h>

#include <time.h>

int main() {

//set initial rowsize and colsize

int rowsize = 10;

int colsize = 10;

//open file to write to

FILE* fp;

fp = fopen("times.csv", "w");

while(rowsize <= 1000) { //keep increasing rowsize till max limit is reached. Depends on available RAM

int arr[rowsize][colsize]; //create array

for(int j = 0; j < rowsize; j++) { //randomly assign values using rand function

for(int k = 0; k < colsize; k++) {

srand(time(0));

arr[j][j] = rand();

}

}

clock_t start, end; //start and end store clock times

double time_row;

start = clock(); //start clock

for(int j = 0; j < rowsize; j ++) { //iterate over all rows

long long int sum = 0; //stores sum

for(int k = 0; k < colsize; k++) { //iterate over all columns

sum += arr[j][k]; //keep adding

}

}

end = clock(); //stop clock

time_row = ((double)(end - start)) / CLOCKS_PER_SEC; //get time taken by adding row operation

double time_col; //repeat the same. This time for column wise sum

start = clock();

for(int j = 0; j < colsize; j ++) {

long long int sum = 0;

for(int k = 0; k < rowsize; k++) {

sum += arr[k][j];

}

}

end = clock();

time_col = ((double)(end - start)) / CLOCKS_PER_SEC;

fprintf(fp, "%lf,%lf,%d,%d\n", time_row, time_col, rowsize, colsize); //print to file

rowsize *= 2; //increase row and colsize

colsize *= 2;

}

fclose(fp);

return 0;

}

SAMPLE RUN:

sample output file produced by program. row_time, col_time, num_rows, num_cols.

.900884, θ·880083 , 16, 1e 3 4 5 000D86 , 0 . 000005, 20 , 2 9·000026, θ . 800018, 46, 46 9.000844 , θ·8日0038,80,BA θ· 600879, θ . 860068, 166, 160 9·000386 , θ , 800295 , 329 , 329 D.801223,0.81582,64,640