28 March 2023 1:52:56.459 PM gen_laguerre_exactness(): FORTRAN90 version Investigate the polynomial exactness of a generalized Gauss-Laguerre quadrature rule by integrating exponentially weighted monomials up to a given degree over the [0,+oo) interval. The rule may be defined on another interval, [A,+oo) in which case it is adjusted to the [0,+oo) interval. gen_laguerre_exactness: User input: Quadrature rule X file = "gen_lag_o4_a0.5_x.txt". Quadrature rule W file = "gen_lag_o4_a0.5_w.txt". Quadrature rule R file = "gen_lag_o4_a0.5_r.txt". Maximum degree to check = 10 Weighting function exponent ALPHA = 0.500000 Spatial dimension = 1 Number of points = 4 The quadrature rule to be tested is a generalized Gauss-Laguerre rule ORDER = 4 A = 0.00000 ALPHA = 0.500000 OPTION = 0, standard rule: Integral ( A <= x < +oo ) x^alpha exp(-x) f(x) dx is to be approximated by sum ( 1 <= I <= ORDER ) w(i) * f(x(i)). Weights W: w( 1) = 0.4530087465586076 w( 2) = 0.3816169601717996 w( 3) = 0.5079462757224078E-01 w( 4) = 0.8065911501100311E-03 Abscissas X: x( 1) = 0.5235260767382691 x( 2) = 2.156648763269094 x( 3) = 5.137387546176711 x( 4) = 10.18243761381592 Region R: r( 1) = 0.000000000000000 r( 2) = 0.1000000000000000E+31 A generalized Gauss-Laguerre rule would be able to exactly integrate monomials up to and including degree = 7 Error Degree 0.0000000000000000 0 0.0000000000000003 1 0.0000000000000004 2 0.0000000000000003 3 0.0000000000000003 4 0.0000000000000006 5 0.0000000000000013 6 0.0000000000000023 7 0.0105306458247668 8 0.0504362510554501 9 0.1330978618904361 10 gen_laguerre_exactness: Normal end of execution. 28 March 2023 1:52:56.459 PM