31 March 2023 10:34:20.384 AM LAGUERRE_EXACTNESS(): FORTRAN90 version Investigate the exactness of a Gauss-Laguerre quadrature rule for integrating monomials with density exp(-x) or density 1 over the [0,+oo) interval. LAGUERRE_EXACTNESS: User input: Quadrature rule X file = "lag_o04_x.txt". Quadrature rule W file = "lag_o04_w.txt". Quadrature rule R file = "lag_o04_r.txt". Maximum degree to check = 10 OPTION = 0, integrate exp(-x)*f(x). Spatial dimension = 1 Number of points = 4 The quadrature rule to be tested is a Gauss-Laguerre rule of ORDER = 4 Integral ( 0.00000 <= x < +oo ) f(x) exp ( -x ) dx Weights W: w( 1) = 0.6031541043416337 w( 2) = 0.3574186924377999 w( 3) = 0.3888790851500538E-01 w( 4) = 0.5392947055613278E-03 Abscissas X: x( 1) = 0.3225476896193923 x( 2) = 1.745761101158346 x( 3) = 4.536620296921128 x( 4) = 9.395070912301136 Region R: r( 1) = 0.000000000000000 r( 2) = 0.1000000000000000E+31 A Gauss-Laguerre rule would be able to exactly integrate monomials up to and including degree = 7 Degree Error 0 0.0000000000000002 1 0.0000000000000002 2 0.0000000000000000 3 0.0000000000000000 4 0.0000000000000003 5 0.0000000000000007 6 0.0000000000000013 7 0.0000000000000022 8 0.0142857142857118 9 0.0650793650793622 10 0.1641269841269810 LAGUERRE_EXACTNESS: Normal end of execution. 31 March 2023 10:34:20.385 AM