Files
2025-02-Numerical/hws/hw3/main.c

345 lines
9.9 KiB
C

#include "nr.h"
#include "nrutil.h"
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/wait.h>
#include "matutil.h"
void try_gaussj(JMatrixData *data) {
printf("gauss-jordan method:\n");
fflush(stdout);
fflush(stderr);
gaussj(data->a, data->m, data->b, 1);
print_matrix(data->m, 1, data->b);
}
void try_lu(JMatrixData *data) {
printf("LU Decomposition:\n");
int *indx = calloc(data->m + 1, sizeof(int));
float *d = calloc(data->m + 1, sizeof(float));
ludcmp(data->a, data->m, indx, d);
print_matrix(data->m, data->n, data->a);
printf("index: ");
print_vector_int(data->m, indx);
printf("solution x: ");
float *b = calloc(data->m + 1, sizeof(float));
int i;
for (i = 1; i <= data->m; i++) {
b[i] = data->b[i][1];
}
lubksb(data->a, data->m, indx, b);
print_vector_float(data->m, b);
free(indx);
free(d);
free(b);
}
void try_svd(JMatrixData *data) {
int i;
printf("Singular Value Decompoisition:\n");
fflush(stdout);
fflush(stderr);
float *w = calloc(data->m + 1, sizeof(float));
float **v = new_matrix(data->m, data->n);
svdcmp(data->a, data->m, data->n, w, v);
printf("U:\n");
print_matrix(data->m, data->n, data->a);
printf("w: ");
print_vector_float(data->m, w);
printf("S:\n");
float **s = new_diagonal(data->m, w);
print_matrix(data->m, data->n, s);
printf("V:\n");
print_matrix(data->m, data->n, v);
printf("\n");
float **t1 = matmul(data->m, data->m, data->m, data->a, s);
float **vt = mattranspose(data->m, data->n, v);
float **t2 = matmul(data->m, data->n, data->m, t1, vt);
printf("Orig = U * S * V^T\n");
print_matrix(data->m, data->n, t2);
printf("we want to get x by using x = V * (S^-1 * (U^T * b)):\n");
printf("x:\n");
float **invS = new_matrix(data->m, data->m);
for (i = 1; i <= data->m; i++) {
invS[i][i] = 1 / w[i];
}
float **UT = mattranspose(data->m, data->n, data->a);
float **l1 = matmul(data->m, data->m, 1, UT, data->b);
float **l2 = matmul(data->m, data->m, 1, invS, l1);
float **l3 = matmul(data->m, data->m, 1, v, l2);
print_matrix(data->m, 1, l3);
simple_free_matrix(data->m, data->n, v);
simple_free_matrix(data->m, data->m, vt);
simple_free_matrix(data->m, data->m, s);
simple_free_matrix(data->m, data->n, t1);
simple_free_matrix(data->m, data->n, t2);
simple_free_matrix(data->m, data->m, invS);
simple_free_matrix(data->m, data->m, UT);
simple_free_matrix(data->m, 1, l1);
simple_free_matrix(data->m, 1, l2);
simple_free_matrix(data->m, 1, l3);
free(w);
}
void try_det_inv(JMatrixData *data) {
int m = data->m;
float det = matdet(m, data->a);
printf("det: %f\n", det);
if (det < 1e-6) {
printf("There is no inverse matrix, because det ~ 0.0f\n");
} else {
float **inv = matinv(m, data->a);
printf("inv:\n");
print_matrix(m, m, inv);
simple_free_matrix(m, m, inv);
}
}
void try_mprove(JMatrixData *data) {
printf("mprove method:\n");
fflush(stdout);
fflush(stderr);
float **a = new_matrix(data->m, data->m);
copy_matrix(data->m, data->m, data->a, a);
int *indx = calloc(data->m + 1, sizeof(int));
float *d = malloc(sizeof(float));
ludcmp(a, data->m, indx, d);
float *x_init = calloc(data->m + 1, sizeof(float));
float *b = calloc(data->m + 1, sizeof(float));
int i;
for (i = 1; i <= data->m; i++) {
x_init[i] = data->b[i][1];
b[i] = data->b[i][1];
}
lubksb(a, data->m, indx, x_init);
float *x = calloc(data->m + 1, sizeof(float));
for (i = 1; i <= data->m; i++) {
x[i] = x_init[i];
}
printf("x_init: ");
print_vector_float(data->m, x_init);
mprove(data->a, a, data->m, indx, b, x);
printf("x using mprove: ");
print_vector_float(data->m, x);
free(x);
free(x_init);
free(indx);
free(d);
simple_free_matrix(data->m, data->m, a);
}
void processMatrix(JMatrixData *data) {
printf("-----------------------------\n");
printf("matrix data A:\n");
print_matrix(data->m, data->n, data->a);
printf("matrix data b:\n");
print_matrix(data->m, 1, data->b);
printf("-----------------------------\n");
fflush(stdout);
fflush(stderr);
pid_t pid = fork();
if (pid < 0) {
printf("process 실행 실패\n");
return;
} else if (pid == 0) {
printf("created process for gauss-jordan method\n");
printf("-----------------------------\n");
JMatrixData *copied = new_jmatdata(data->m, data->n);
copy_jmatdata(data, copied);
try_gaussj(copied);
free_jmatdata(copied);
printf("-----------------------------\n");
exit(0);
}
wait(NULL);
fflush(stdout);
fflush(stderr);
pid = fork();
if (pid < 0) {
printf("process 실행 실패\n");
return;
} else if (pid == 0) {
printf("created process for LU Decomposition\n");
printf("-----------------------------\n");
fflush(stdout);
fflush(stderr);
JMatrixData *copied = new_jmatdata(data->m, data->n);
copy_jmatdata(data, copied);
try_lu(copied);
free_jmatdata(copied);
printf("-----------------------------\n");
exit(0);
}
wait(NULL);
fflush(stdout);
fflush(stderr);
pid = fork();
if (pid < 0) {
printf("process 실행 실패\n");
return;
} else if (pid == 0) {
printf("created process for Singular Value Decomposition\n");
printf("-----------------------------\n");
fflush(stdout);
fflush(stderr);
JMatrixData *copied = new_jmatdata(data->m, data->n);
copy_jmatdata(data, copied);
try_svd(copied);
free_jmatdata(copied);
printf("-----------------------------\n");
exit(0);
}
wait(NULL);
fflush(stdout);
fflush(stderr);
pid = fork();
if (pid < 0) {
printf("process 실행 실패\n");
return;
} else if (pid == 0) {
printf("created process for LUDecomp with mprove\n");
printf("-----------------------------\n");
fflush(stdout);
fflush(stderr);
JMatrixData *copied = new_jmatdata(data->m, data->n);
copy_jmatdata(data, copied);
try_mprove(copied);
free_jmatdata(copied);
printf("-----------------------------\n");
exit(0);
}
wait(NULL);
fflush(stdout);
fflush(stderr);
printf("last we want to get det and inv of A:\n");
pid = fork();
if (pid < 0) {
printf("process 실행 실패\n");
return;
} else if (pid == 0) {
printf("created process for det and inv\n");
printf("-----------------------------\n");
fflush(stdout);
fflush(stderr);
JMatrixData *copied = new_jmatdata(data->m, data->n);
copy_jmatdata(data, copied);
try_det_inv(copied);
free_jmatdata(copied);
printf("-----------------------------\n");
exit(0);
}
wait(NULL);
fflush(stdout);
fflush(stderr);
}
JMatrixData *readDataFrom(char *filename) {
FILE *fp = fopen(filename, "r");
if (fp == NULL) {
printf("Error opening file");
exit(1);
}
int m, n;
fscanf(fp, "%d", &m);
fscanf(fp, "%d", &n);
JMatrixData *data = new_jmatdata(m, n);
int i, j;
for (i = 1; i <= data->m; i++) {
for (j = 1; j <= data->n; j++) {
fscanf(fp, "%f", &data->a[i][j]);
}
}
for (i = 1; i <= data->m; i++) {
fscanf(fp, "%f", &data->b[i][1]);
}
fclose(fp);
return data;
}
int main() {
int m, n;
int i, j;
const char *filenames[] = {
"lineq1.dat", "lineq2.dat", "lineq3.dat"};
pid_t pid;
for (i = 0; i < 3; i++) {
pid = fork();
fflush(stdout);
fflush(stderr);
if (pid < 0) {
printf("process 실행 실패\n");
return 2;
} else if (pid == 0) {
printf("=================================\n");
printf("data from %s:\n", filenames[i]);
JMatrixData *data = readDataFrom(filenames[i]);
processMatrix(data);
printf("end for %s\n", filenames[i]);
exit(0);
}
wait(NULL);
}
fflush(stdout);
fflush(stderr);
printf("=======================================\n");
printf("===============< Report >==============\n");
printf("=======================================\n");
printf("# 1. discuss three method.\n");
printf("In terms of the accuracy of the solution,\nthere is no noticable difference between three methods.(at 1e-6)\n");
printf("But `gaussj` method is unstable when there are many solutions.\n");
printf("In terms of stability, svdcmp is the most stable\nbecause the solution can always come out (because it is, by definition, expressed as matmul).\n");
printf("I could not feel it in this example\nbut I think svd is the slowest for that; matmul is too expensive.\n");
printf("so I think that LUdcmp is balanced:\nNot as unstable as gaussj, not as expensive as svdcmp.\n");
printf("# 2. mprove\n");
printf("`mprove` is a method of increasing the accuracy of the solution\nby using an iterative method using the alud and initial solution obtained by `ludcmp`.\n");
printf("The accuracy of the LU can be compensated using this method,\nso the LUdcmp is getting more useful.\n");
printf("# 3. det and inv\n");
printf("Without first example, we can get inverse matrix with gaussj.\n");
printf("We can also get determinants using cofactor expansion with recursive method.\n");
printf("=======================================\n");
printf("=============< End Report >============\n");
printf("=======================================\n");
return 0;
}