3 February 2008 11:45:59.244 AM INT_EXACTNESS_GEN_LAGUERRE 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. INT_EXACTNESS_GEN_LAGUERRE: User input: Quadrature rule X file = "gen_lag_o8_a0.5_x.txt". Quadrature rule W file = "gen_lag_o8_a0.5_w.txt". Quadrature rule R file = "gen_lag_o8_a0.5_r.txt". Maximum degree to check = 18 Weighting function exponent ALPHA = 0.500000 Spatial dimension = 1 Number of points = 8 The quadrature rule to be tested is a generalized Gauss-Laguerre rule ORDER = 8 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) = 0.2271393619524718 w( 2) = 0.3935945428036146 w( 3) = 0.2129089708672283 w( 4) = 0.4787748320313819E-01 w( 5) = 0.4542517474762639E-02 w( 6) = 0.1624046001853258E-03 w( 7) = 0.1642377413806097E-05 w( 8) = 0.2173943126630915E-08 Abscissas X: x( 1) = 0.2826336481165992 x( 2) = 1.139873801581614 x( 3) = 2.601524843406029 x( 4) = 4.724114537527790 x( 5) = 7.605256299231614 x( 6) = 11.41718207654583 x( 7) = 16.49941079765582 x( 8) = 23.73000399593471 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 = 15 Error Degree 0.0000000000000001 0 0.0000000000000002 1 0.0000000000000003 2 0.0000000000000002 3 0.0000000000000000 4 0.0000000000000004 5 0.0000000000000004 6 0.0000000000000004 7 0.0000000000000007 8 0.0000000000000008 9 0.0000000000000008 10 0.0000000000000015 11 0.0000000000000018 12 0.0000000000000033 13 0.0000000000000053 14 0.0000000000000045 15 0.0000561671454578 16 0.0004926661044402 17 0.0022799523824517 18 INT_EXACTNESS_GEN_LAGUERRE: Normal end of execution. 3 February 2008 11:45:59.247 AM