@Test
public void moreOpsTest() {
double[][] basicArray = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}, {10, 11, 12}};
Matrix m = new Matrix(basicArray);
/** MINOR ARRAY (2, 2) */
double[][] minorArr = {{1, 3}, {7, 9}, {10, 12}};
assertTrue(m.minor(2, 2).equals(new Matrix(minorArr)));
/** DETERMINANT AND INVERSE */
double[][] basicSquare = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
Matrix basicSquareMatrix = new Matrix(basicSquare);
assertTrue(basicSquareMatrix.det() == 0);
assertFalse(basicSquareMatrix.invertible()); // since det = 0;
double[][] invertibleArr = {{7, 2, 1}, {0, 3, -1}, {-3, 4, -2}};
Matrix invertibleMatrix = new Matrix(invertibleArr);
double[][] inverse = {{-2, 8, -5}, {3, -11, 7}, {9, -34, 21}};
assertTrue(invertibleMatrix.inverse().equals(new Matrix(inverse)));
/** ECHELON FORM */
double[][] echelonRes1 = {{1, 2, 0}, {0, 1, 1.25}, {0, 0, 1}};
Matrix echelonMatrix1 = new Matrix(echelonRes1);
double[][] testArr = {{1, 2, 0}, {0, 4, 5}, {3, 2, 6}};
Matrix testMatrix = new Matrix(testArr);
testMatrix.echelonForm();
double[][] testArr2 = {{0, 4, 5}, {1, 2, 0}, {3, 2, 6}};
Matrix testMatrix2 = new Matrix(testArr2);
testMatrix2.echelonForm();
assertTrue(testMatrix.equals(echelonMatrix1));
assertTrue(testMatrix2.equals(echelonMatrix1));
double[][] identityArr = {{1, 0, 0}, {0, 1, 0}, {0, 0, 1}};
Matrix identityMatrix = new Matrix(identityArr);
testMatrix.reducedEchelonForm();
assertTrue(testMatrix.equals(identityMatrix));
double[][] moreRows = {{4, 5}, {2, 1}, {0, 0}};
Matrix moreRowsMatrix = new Matrix(moreRows);
double[][] goodMoreRows = {{1, 0}, {0, 1}, {0, 0}};
Matrix goodMoreRowsMatrix = new Matrix(goodMoreRows);
moreRowsMatrix.reducedEchelonForm();
assertTrue(moreRowsMatrix.equals(goodMoreRowsMatrix));
double[][] moreCols = {{2, 4, 8}, {1, 2, 9}};
Matrix moreColsMatrix = new Matrix(moreCols);
double[][] goodMoreCols = {{1, 2, 0}, {0, 0, 1}};
Matrix goodMoreColsMatrix = new Matrix(goodMoreCols);
moreColsMatrix.reducedEchelonForm();
assertTrue(moreColsMatrix.equals(goodMoreColsMatrix));
/** PIVOT COUNT */
assertTrue(moreColsMatrix.pivots() == 2);
assertTrue(moreRowsMatrix.pivots() == 2);
assertTrue(testMatrix.pivots() == 3);
}
