### Question:
LinearAlgebraUtils { public static DoubleMatrix matTxmat(DoubleMatrix matrix1, DoubleMatrix matrix2) { return matrix1.transpose().mmul(matrix2); }  static double[] solve22(double[][] A, double[] y); static double[] solve33(double[][] A, double[] rhs); static DoubleMatrix absMatrix(DoubleMatrix inMatrix); static double[][] absMatrix(double[][] inMatrix); static DoubleMatrix matrixPower(DoubleMatrix data, double scalar); static double[][] matrixPower(double[][] inMatrix, double scalar); static void invertChol_inplace(double[][] inMatrix); static double[][] invertChol(double[][] inMatrix); static void invertChol_inplace(DoubleMatrix inMatrix); static DoubleMatrix invertChol(DoubleMatrix inMatrix); static ComplexDoubleMatrix dotmult(ComplexDoubleMatrix A, ComplexDoubleMatrix B); static void dotmult_inplace(ComplexDoubleMatrix A, ComplexDoubleMatrix B); static void fliplr_inplace(DoubleMatrix A); static DoubleMatrix matTxmat(DoubleMatrix matrix1, DoubleMatrix matrix2); static ComplexDoubleMatrix matTxmat(ComplexDoubleMatrix matrix1, ComplexDoubleMatrix matrix2); static void wshift_inplace(DoubleMatrix inVector, int n); static DoubleMatrix wshift(DoubleMatrix inMatrix, int n); static void setdata(DoubleMatrix outMatrix, Window outWin, DoubleMatrix inMatrix, Window inWin); static void setdata(ComplexDoubleMatrix outMatrix, Window outWin, ComplexDoubleMatrix inMatrix, Window inWin); static void setdata(ComplexDoubleMatrix outMatrix, ComplexDoubleMatrix inMatrix, Window inWin); static void setdata(DoubleMatrix outMatrix, DoubleMatrix inMatrix, Window inWin); static void chol_inplace(double[][] inMatrix); static void chol_inplace(DoubleMatrix inMatrix); static void invert_inplace(double[][] inMatrix); static double[][] invert(double[][] inMatrix); static void invert_inplace(DoubleMatrix inMatrix); static DoubleMatrix invert(DoubleMatrix inMatrix); static void arrangeCholesky_inplace(DoubleMatrix inMatrix); static void arrangeCholesky_inplace(double[][] inArray);  }### Answer:
@Test public void testMatTxmatDouble_JBLAS() throws Exception { DoubleMatrix ATA_33_ACTUAL = LinearAlgebraUtils.matTxmat(A_33, A_33); Assert.assertEquals(ATA_33_EXPECTED, ATA_33_ACTUAL); }
@Test public void testMatTxmatComplex_JBLASS() throws Exception { ComplexDoubleMatrix ATA_33_CPLX_ACTUAL = LinearAlgebraUtils.matTxmat(new ComplexDoubleMatrix(A_33, A_33), new ComplexDoubleMatrix(A_33, A_33)); ComplexDoubleMatrix ATA_33_CPLX_EXPECTED = new ComplexDoubleMatrix(DoubleMatrix.zeros(A_33.rows, A_33.columns), ATA_33_EXPECTED.mmul(2)); Assert.assertEquals(ATA_33_CPLX_EXPECTED, ATA_33_CPLX_ACTUAL); }