Matrix3 { public Matrix3 invertMatrix(Matrix3 matrix) { if (matrix == null) { throw new IllegalArgumentException( Logger.logMessage(Logger.ERROR, "Matrix3", "invertMatrix", "missingMatrix")); } throw new UnsupportedOperationException("Matrix3.invertMatrix is not implemented"); } Matrix3();  Matrix3(double m11, double m12, double m13,
                   double m21, double m22, double m23,
                   double m31, double m32, double m33);  Matrix3(Matrix3 matrix); @Override boolean equals(Object o); @Override int hashCode(); @Override String toString(); Matrix3 set(double m11, double m12, double m13,
                       double m21, double m22, double m23,
                       double m31, double m32, double m33); Matrix3 set(Matrix3 matrix); Matrix3 setTranslation(double x, double y); Matrix3 setRotation(double angleDegrees); Matrix3 setScale(double xScale, double yScale); Matrix3 setToIdentity(); Matrix3 setToTranslation(double x, double y); Matrix3 setToRotation(double angleDegrees); Matrix3 setToScale(double xScale, double yScale); Matrix3 setToVerticalFlip(); Matrix3 setToTileTransform(Sector src, Sector dst); Matrix3 setToMultiply(Matrix3 a, Matrix3 b); Matrix3 multiplyByTranslation(double x, double y); Matrix3 multiplyByRotation(double angleDegrees); Matrix3 multiplyByScale(double xScale, double yScale); Matrix3 multiplyByVerticalFlip(); Matrix3 multiplyByTileTransform(Sector src, Sector dst); Matrix3 multiplyByMatrix(Matrix3 matrix); Matrix3 multiplyByMatrix(double m11, double m12, double m13,
                                    double m21, double m22, double m23,
                                    double m31, double m32, double m33); Matrix3 transpose(); Matrix3 transposeMatrix(Matrix3 matrix); float[] transposeToArray(float[] result, int offset); Matrix3 invert(); Matrix3 invertMatrix(Matrix3 matrix); final double[] m; }
@Ignore("invertMatrix was not implemented at time of test") @Test public void testInvertMatrix() throws Exception { Matrix3 m1 = new Matrix3(); Matrix3 m2 = new Matrix3( -4, -3, 3, 0, 2, -2, 1, 4, -1); double det = computeDeterminant(m2); System.out.println(m2); System.out.println("Determinate: " + det); Matrix3 mInv = m1.invertMatrix(m2); Matrix3 mIdentity = mInv.multiplyByMatrix(m2); assertArrayEquals("identity matrix array", Matrix3.identity, mIdentity.m, 0); assertSame("fluent api result", mInv, m1); }