3 February 2008 11:45:59.274 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_x.txt". Quadrature rule W file = "gen_lag_o16_a0.5_w.txt". Quadrature rule R file = "gen_lag_o16_a0.5_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 = 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) = 0.9774098913713274E-01 w( 2) = 0.2523079012122731 w( 3) = 0.2724198251520776 w( 4) = 0.1716635071262904 w( 5) = 0.6954026102655395E-01 w( 6) = 0.1873480877845603E-01 w( 7) = 0.3381229238954949E-02 w( 8) = 0.4052556900801655E-03 w( 9) = 0.3156131814886896E-04 w(10) = 0.1541304259364148E-05 w(11) = 0.4474937802762097E-07 w(12) = 0.7136037163751600E-09 w(13) = 0.5532849784136906E-11 w(14) = 0.1703727514691121E-13 w(15) = 0.1418249588844851E-16 w(16) = 0.1213712303922958E-20 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 0.0000000000000006 0 0.0000000000000012 1 0.0000000000000013 2 0.0000000000000008 3 0.0000000000000004 4 0.0000000000000002 5 0.0000000000000001 6 0.0000000000000005 7 0.0000000000000007 8 0.0000000000000008 9 0.0000000000000016 10 0.0000000000000004 11 0.0000000000000028 12 0.0000000000000025 13 0.0000000000000060 14 0.0000000000000049 15 0.0000000000000000 16 0.0000000000000038 17 0.0000000000000040 18 0.0000000000000014 19 0.0000000000000052 20 0.0000000000000032 21 0.0000000000000006 22 0.0000000000000089 23 0.0000000000000031 24 0.0000000000000046 25 0.0000000000000030 26 0.0000000000000011 27 0.0000000000000034 28 0.0000000000000086 29 0.0000000000000045 30 0.0000000000000022 31 0.0000000011898415 32 0.0000000199430896 33 0.0000001720073255 34 0.0000010170435789 35 INT_EXACTNESS_GEN_LAGUERRE: Normal end of execution. 3 February 2008 11:45:59.279 AM