fix final main.c matutil.c matutil.h and add hw3.txt and README.md

hws/hw3/matutil.c

@@ -1,23 +1,42 @@
 #include "matutil.h"
 
+#define FLOAT_FORMAT "%10.7f "
+
 void print_vector_float(int size, float *v) {
     int i;
-    for (i = 0; i < size; i++) {
-        printf("%6.2f ", v[i]);
+    for (i = 1; i <= size; i++) {
+        printf(FLOAT_FORMAT, v[i]);
     }
     printf("\n");
 }
 
 void print_vector_int(int size, int *v) {
     int i;
-    for (i = 0; i < size; i++) {
+    for (i = 1; i <= size; i++) {
         printf("%d ", v[i]);
     }
     printf("\n");
 }
 
 float **new_matrix(int m, int n) {
-    return matrix(1, m, 1, n);
+    float **mat = matrix(1, m, 1, n);
+    int i, j;
+    for (i = 1; i <= m; i++) {
+        for (j = 1; j <= n; j++) {
+            mat[i][j] = 0;
+        }
+    }
+    return mat;
+}
+
+float **new_diagonal(int n, float *v) {
+    float **mat = new_matrix(n, n);
+    int i;
+    for (i = 1; i <= n; i++) {
+        mat[i][i] = v[i];
+    }
+
+    return mat;
 }
 
 void simple_free_matrix(int m, int n, float **mat) {
@@ -28,7 +47,7 @@ void print_matrix(int m, int n, float **mat) {
     int i, j;
     for (i = 1; i <= m; i++) {
         for (j = 1; j <= n; j++) {
-            printf("%6.2f ", mat[i][j]);
+            printf(FLOAT_FORMAT, mat[i][j]);
         }
         printf("\n");
     }
@@ -43,6 +62,92 @@ void copy_matrix(int m, int n, float **src, float **dst) {
     }
 }
 
+float **matmul(int m, int n, int p, float **a, float **b) {
+    float **c = new_matrix(m, p);
+    int i, j, k;
+
+    for (i = 1; i <= m; i++) {
+
+        for (j = 1; j <= p; j++) {
+            c[i][j] = 0;
+
+            for (k = 1; k <= n; k++) {
+
+                c[i][j] += a[i][k] * b[k][j];
+            }
+        }
+    }
+
+    return c;
+}
+
+float **mattranspose(int m, int n, float **mat) {
+    float **t = new_matrix(n, m);
+    int i, j;
+    for (i = 1; i <= m; i++) {
+        for (j = 1; j <= n; j++) {
+            t[j][i] = mat[i][j];
+        }
+    }
+    return t;
+}
+
+float **matinv(int m, float **mat) {
+    float **inv = new_matrix(m, m);
+    int i, j;
+    for (i = 1; i <= m; i++) {
+        for (j = 1; j <= m; j++) {
+            if (i == j) {
+                inv[i][j] = 1;
+            } else {
+                inv[i][j] = 0;
+            }
+        }
+    }
+    gaussj(mat, m, inv, m);
+    return inv;
+}
+
+void create_submatrix(float **matrix, float **sub_matrix, int n, int exclude_col) {
+    int sub_i = 1;
+    int i, j;
+    for (i = 2; i <= n; i++) {
+        int sub_j = 1;
+        for (j = 1; j <= n; j++) {
+            if (j == exclude_col) {
+                continue;
+            }
+            sub_matrix[sub_i][sub_j] = matrix[i][j];
+            sub_j++;
+        }
+        sub_i++;
+    }
+}
+
+float matdet(int m, float **mat) {
+    if (m == 1) {
+        return mat[1][1];
+    } else if (m == 2) {
+        return mat[1][1] * mat[2][2] - mat[1][2] * mat[2][1];
+    }
+
+    float det = .0f;
+
+    float **submat = new_matrix(m - 1, m - 1);
+    int i, j;
+    for(i = 1; i <= m; i ++) {
+        create_submatrix(mat, submat, m, i);
+        float sign = (i % 2 == 0) ? -1 : 1;
+        
+        float el = mat[1][i];
+
+        det += el * sign * matdet(m-1, submat);
+    }
+
+    simple_free_matrix(m - 1, m - 1, submat);
+    return det;
+}
+
 /* for JMatrixData */
 
 void copy_jmatdata(JMatrixData *src, JMatrixData *dst) {