126 lines
3.4 KiB
C++
126 lines
3.4 KiB
C++
#include "elimination.h"
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#include "math.h"
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FracturedMatrix::FracturedMatrix(const FracturedMatrix& other) : A(other.A), C(other.C), b(other.b), pivot_column_index(other.pivot_column_index), pivot_row_index(other.pivot_row_index) {}
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FracturedMatrix::FracturedMatrix(Matrix A, Vector C, Vector b, int pivot_column_index, int pivot_row_index) : A(A), C(C), b(b), pivot_column_index(pivot_column_index), pivot_row_index(pivot_row_index) {}
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FracturedMatrix& FracturedMatrix::operator=(const FracturedMatrix& other) {
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A = other.A;
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C = other.C;
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b = other.b;
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pivot_column_index = other.pivot_column_index;
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pivot_row_index = other.pivot_row_index;
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return *this;
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}
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DestroyMatrix disassembleGeneralMatrix(Matrix& generalMatrix) {
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int rows = generalMatrix.getRows();
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int cols = generalMatrix.getColumns();
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Matrix A(rows - 1, cols - 1);
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Vector C(cols - 1);
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Vector b(rows);
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for (int j = 0; j < cols - 1; ++j) {
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C[j] = generalMatrix[0][j];
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}
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for (int i = 0; i < rows; ++i) {
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b[i] = generalMatrix[i][cols - 1];
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}
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for (int i = 1; i < rows; ++i) {
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for (int j = 0; j < cols - 1; ++j) {
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A[i - 1][j] = generalMatrix[i][j];
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}
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}
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return {A, C, b};
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}
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Matrix createGeneralMatrix(Matrix& A, Vector& C, Vector& b) {
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int m = A.getRows() + 1;
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int n = A.getColumns() + 1;
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// States if equation has a slack variable
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std::vector<bool> has_slack(A.getColumns(), false);
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int number_of_slack = 0;
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for (int j = 0; j < A.getColumns(); ++j) {
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int basic_var_index = 0;
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int ones = 0;
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int zeros = 0;
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for (int i = 0; i < A.getRows(); ++i) {
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if (A[i][j] == 1) {
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basic_var_index = i;
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++ones;
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} else if (A[i][j] == 0) {
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++zeros;
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}
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}
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if (ones + zeros == A.getRows()) {
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has_slack[basic_var_index] = true;
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number_of_slack += 1;
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}
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}
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n = n + A.getRows() - number_of_slack;
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Matrix generalMatrix(m, n);
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for (int i = 0; i < n; i++) {
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if (i < C.size()) {
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generalMatrix[0][i] = C[i];
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} else {
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generalMatrix[0][i] = 0;
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}
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}
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// For objective function (j=0) the value is set to zero one step before
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for (int j = 1; j < m; j++) {
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generalMatrix[j][n-1] = b[j-1];
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}
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int k = 0;
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for (int i = 0; i < m - 1; i++) {
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for (int j = 0; j < n - 1; j++) {
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if (j < A.getColumns()) {
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generalMatrix[i + 1][j] = A[i][j];
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} else {
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generalMatrix[i + 1][j] = 0;
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}
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}
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if (!has_slack[i]) {
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generalMatrix[i + 1][A.getColumns() + k] = 1;
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++k;
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}
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}
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return generalMatrix;
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}
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void elimination(Matrix& generalMatrix, int pivot_row_index, int pivot_column_index) {
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int rows = generalMatrix.getRows();
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int cols = generalMatrix.getColumns();
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double pivotElement = generalMatrix[pivot_row_index][pivot_column_index];
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for (int j = 0; j < cols; ++j) {
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generalMatrix[pivot_row_index][j] /= pivotElement;
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}
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for (int i = 0; i < rows; ++i) {
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if (i == pivot_row_index)
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continue;
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double pivotColumnCoefficient = generalMatrix[i][pivot_column_index];
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for (int j = 0; j < cols; ++j) {
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generalMatrix[i][j] -= pivotColumnCoefficient * generalMatrix[pivot_row_index][j];
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}
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}
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}
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