void powMatrix(int **C, int **A, int k,
int ***powers,
char *computed,
int N)
{
int **T, i;
T = (int **) malloc(MAX_N * sizeof(int *));
for ( i=0; i<MAX_N; ++i )
T[i] = (int *) malloc(MAX_N * sizeof(int));
if ( (int)computed[k] ) cpyMatrix(C, A, N);
else {
if ( k==1 )
cpyMatrix(powers[k], A, N);
else if ( k%2==0 ) {
powMatrix(T, A, k/2, powers, computed, N);
mulMatrix(powers[k], T, T, N);
}
else {
powMatrix(T, A, k-1, powers, computed, N);
mulMatrix(powers[k], A, T, N);
}
computed[k] = 1;
cpyMatrix(C, powers[k], N);
}
for ( i=0; i<MAX_N; ++i )
free(T[i]);
free(T);
}
int main(int argc, char const *argv[]) {
printf("\nEnter matrix filename, or type 'enter' to enter.\n");
char promptString[100];
scanf("%s", promptString);
if (strcmp(promptString, "enter") == 0) {
printf("Enter the number of rows: ");
scanf("%d", &rows);
printf("Enter the number of columns: ");
scanf("%d", &columns);
printf("\nNote: you can enter '|' to place the augmentation bar.\n");
for (int i = 0; i < rows; ++i) {
for (int j = 0; j < columns; ++j) {
double input;
printf("Row %d Column %d: ", i+1, j+1);
scanf("%lf", &(input));
matrix[i][j] = input;
}
}
}
else {
mtrxFromFile(promptString);
}
// Backup
cpyMatrix(matrix, prevMatrix);
printf("\n");
// Main loop
while (true) {
// Print matrix
printMatrix();
// Get command
printf("\nCommand: ('a'dd, 'm'ul, 's'wap, 'u'ndo, 'r'un solver): ");
char command[5];
scanf("%s", command);
if (command[0] == 'a') {
// Backup
cpyMatrix(matrix, prevMatrix);
int row;
printf(" target row: ");
scanf("%d", &row);
int srcRow;
printf(" source row: ");
scanf("%d", &srcRow);
double factor;
printf(" factor: ");
scanf("%lf", &factor);
mtrxAdd(matrix, row, srcRow, factor);
}
else if (command[0] == 'm') {
// Backup
cpyMatrix(matrix, prevMatrix);
int row;
printf(" row: ");
scanf("%d", &row);
double factor;
printf(" factor: ");
scanf("%lf", &factor);
mtrxMult(matrix, row, factor);
}
else if (command[0] == 's') {
// Backup
cpyMatrix(matrix, prevMatrix);
int row1;
printf(" target row: ");
scanf("%d", &row1);
int row2;
printf(" source row: ");
scanf("%d", &row2);
mtrxSwap(matrix, row1, row2);
}
else if (command[0] == 'u') {
printf("\n\nUNDO. You may only undo once at a time.\n");
cpyMatrix(prevMatrix, matrix);
}
else if (command[0] == 'r') {
// Backup
cpyMatrix(matrix, prevMatrix);
// Rest all pivots
pivotRow = 0;
pivotColumn = 0;
while (pickAndSwapPivot()) {
if (matrix[pivotRow - 1][pivotColumn - 1] != 1) {
// Scale
double factor = 1.0 / matrix[pivotRow - 1][pivotColumn - 1];
mtrxMult(matrix, pivotRow, factor);
}
// Clear column
for (int i = 0; i < rows; ++i) {
if (i == pivotRow - 1) continue;
double value = matrix[i][pivotColumn - 1];
if (fabs(value) >= ZERO_THRESH) {
// Subtract multiples
mtrxAdd(matrix, i + 1, pivotRow, -value);
}
}
printMatrix();
}
printf("\nSolved matrix.\n");
}
else {
printf("\n\nRETRY. Use only one letter.\n");
}
printf("\n");
}
return 0;
}
