3 February 2008 11:45:59.415 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_o16_a0.5_modified_x.txt". Quadrature rule W file = "gen_lag_o16_a0.5_modified_w.txt". Quadrature rule R file = "gen_lag_o16_a0.5_modified_r.txt". Maximum degree to check = 35 Weighting function exponent ALPHA = 0.500000 Spatial dimension = 1 Number of points = 16 The quadrature rule to be tested is a generalized Gauss-Laguerre rule ORDER = 16 A = 0.00000 ALPHA = 0.500000 OPTION = 1, modified rule: Integral ( A <= x < oo ) f(x) dx is to be approximated by sum ( 1 <= I <= ORDER ) w(i) * f(x(i)). Weights W: w( 1) = 0.2950148257926292 w( 2) = 0.5926504061509453 w( 3) = 0.8956575998744516 w( 4) = 1.207063433953284 w( 5) = 1.530352787791976 w( 6) = 1.869714179339352 w( 7) = 2.230395748423061 w( 8) = 2.619252244761896 w( 9) = 3.045634801992271 w(10) = 3.522929682017350 w(11) = 4.071417057880741 w(12) = 4.724080738693911 w(13) = 5.539909876059123 w(14) = 6.639993574123777 w(15) = 8.335658835078922 w(16) = 11.89633502881635 Abscissas X: x( 1) = 0.1473991846163110 x( 2) = 0.5909018112431889 x( 3) = 1.334487511614577 x( 4) = 2.385011552004654 x( 5) = 3.752567873874769 x( 6) = 5.451062939568397 x( 7) = 7.499085532907372 x( 8) = 9.921219136072430 x( 9) = 12.75005546011707 x(10) = 16.02938636037513 x(11) = 19.81951287710202 x(12) = 24.20668064346831 x(13) = 29.32145610335233 x(14) = 35.37955078717556 x(15) = 42.79325597075464 x(16) = 52.61836625575324 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 = 31 Error Degree 0.0000000000000005 0 0.0000000000000012 1 0.0000000000000013 2 0.0000000000000006 3 0.0000000000000004 4 0.0000000000000002 5 0.0000000000000001 6 0.0000000000000000 7 0.0000000000000001 8 0.0000000000000002 9 0.0000000000000002 10 0.0000000000000024 11 0.0000000000000008 12 0.0000000000000046 13 0.0000000000000044 14 0.0000000000000034 15 0.0000000000000015 16 0.0000000000000028 17 0.0000000000000035 18 0.0000000000000009 19 0.0000000000000054 20 0.0000000000000032 21 0.0000000000000008 22 0.0000000000000088 23 0.0000000000000031 24 0.0000000000000048 25 0.0000000000000028 26 0.0000000000000015 27 0.0000000000000029 28 0.0000000000000078 29 0.0000000000000055 30 0.0000000000000028 31 0.0000000011898407 32 0.0000000199430886 33 0.0000001720073247 34 0.0000010170435781 35 INT_EXACTNESS_GEN_LAGUERRE: Normal end of execution. 3 February 2008 11:45:59.419 AM