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#include <stdio.h> | |
#include <unistd.h> | |
#include <stdlib.h> | |
#include <string.h> | |
#include <sys/types.h> | |
#include <sys/wait.h> | |
// select TEST 1 or 2. TEST=0 reads from stdin | |
#ifndef DO_TEST | |
#define DO_TEST 1 | |
#endif | |
#if DO_TEST > 0 | |
const char *test_input1[] = { | |
"2", // n | |
"1", "2", // A | |
"3", "4", | |
"1", "2", // B | |
"3", "4", | |
}; | |
const char *test_input2[] = { | |
"2", // n | |
"1", "0", // A | |
"0", "1", | |
"1", "0", // B | |
"0", "1", | |
}; | |
#define INP(F, D) do { sscanf(*line, F, D); line++; } while (0) | |
#else | |
#define INP(F, D) scanf(F, D) | |
#endif | |
// Program Structure | |
enum program_constants { max_dimension = 10 }; | |
struct context { | |
int max; | |
int pfd[2]; // pipe | |
pid_t pid[max_dimension]; // subprocesses | |
int A[max_dimension][max_dimension]; | |
int B[max_dimension][max_dimension]; | |
int C[max_dimension][max_dimension]; | |
}; | |
static int init_context(struct context* C); | |
static int start_jobs(struct context* C); | |
static int read_result(struct context* C); | |
// Program main | |
int main(int argc, char* argv[]) | |
{ | |
struct context C; | |
int err; | |
if (0 != (err = init_context(&C))) { | |
return err; | |
} else if (0 != (err = start_jobs(&C))) { | |
return err; | |
} else if(0 != (err = read_result(&C))) { | |
return err; | |
} else { | |
return 0; | |
} | |
} | |
// Functions | |
int init_context(struct context* C) | |
{ | |
int i,j; | |
#if DO_TEST == 1 | |
const char** line = test_input1; | |
#elif DO_TEST == 2 | |
const char** line = test_input2; | |
#endif | |
printf("Enter the size (%d)", getpid() ); | |
INP("%d", &C->max); | |
if (0 < C->max && C->max < max_dimension) { | |
for(i = 0;i < C->max; i++) | |
{ | |
printf("Enter row %d of your matrix A: ", i); | |
for(j=0;j<C->max;j++) | |
{ | |
INP("%d",&C->A[i][j]); | |
} | |
} | |
// Get input for the first matrix | |
for(i = 0; i < C->max; i++) | |
{ | |
printf("Enter row %d of your matrix B: ", i); | |
for(j=0;j<C->max;j++) | |
{ | |
INP("%d",&C->B[i][j]); | |
} | |
} | |
// Get input for the second matrix | |
printf("\n"); | |
return 0; | |
} else { | |
return -1; // dimension must be in [1,max_dimension[ | |
} | |
} | |
int start_jobs(struct context* C) | |
{ | |
int i; | |
int comm[2]; | |
if(pipe(C->pfd)==-1) | |
{ | |
fprintf(stderr,"Error\n"); | |
exit(1); | |
} | |
for(i = 0; i < C->max; i++) | |
{ | |
C->pid[i]=fork(); | |
if((C->pid[i])==0) | |
{ | |
int j, prod, c; | |
printf("CHLD %i %d\n", i, getpid()); | |
close(C->pfd[0]); | |
for(j = 0; j < C->max; j++) | |
{ | |
prod=0; | |
for(c = 0; c < C->max; c++) | |
{ | |
//printf("A: %d, B: %d\n", C->A[i][c], C->B[c][j]); | |
prod += C->A[i][c]*C->B[c][j]; | |
} | |
printf("A_%d_S * B_S_%d = %d\n", i, j,prod); | |
comm[0] = i; comm[1] = prod; | |
write(C->pfd[1], comm, sizeof comm); | |
} | |
exit(0); | |
} else if (C->pid[i] < 0) { | |
return -1; // a fork failed | |
} | |
} | |
return 0; // all processes started. | |
} | |
int read_result(struct context* C) | |
{ | |
int i, j, _k, k[max_dimension], finalprod; | |
int status; | |
int comm[2]; | |
memset(k, 0, sizeof k); | |
for(j = 0; j < C->max; j++) | |
{ | |
if(C->pid[j] != 0) | |
{ | |
for(_k = 0; _k < C->max; _k++) | |
{ | |
read(C->pfd[0], comm, sizeof comm); | |
i = comm[0]; finalprod = comm[1]; | |
C->C[k[i]][i] = finalprod; | |
printf("C[%d][%d] = %d\n", k[i], i, C->C[k[i]][i]); | |
++k[i]; | |
} | |
} | |
} | |
for(j = 0; j < C->max; j++) { | |
waitpid(C->pid[j],&status,0); | |
} | |
return 0; | |
} |
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we need to move the
k
index in a row ordered way.