function [ t, wts ] = cdgqf ( nt, kind, alpha, beta ) %*****************************************************************************80 % %% CDGQF computes a Gauss quadrature formula with default A, B and simple knots. % % Discussion: % % This routine computes all the knots and weights of a Gauss quadrature % formula with a classical weight function with default values for A and B, % and only simple knots. % % There are no moments checks and no printing is done. % % Use routine EIQFS to evaluate a quadrature computed by CGQFS. % % Licensing: % % This code is distributed under the GNU LGPL license. % % Modified: % % 04 January 2010 % % Author: % % Original FORTRAN77 version by Sylvan Elhay, Jaroslav Kautsky. % MATLAB version by John Burkardt. % % Reference: % % Sylvan Elhay, Jaroslav Kautsky, % Algorithm 655: IQPACK, FORTRAN Subroutines for the Weights of % Interpolatory Quadrature, % ACM Transactions on Mathematical Software, % Volume 13, Number 4, December 1987, pages 399-415. % % Parameters: % % Input, integer NT, the number of knots. % % Input, integer KIND, the rule. % 1, Legendre, (a,b) 1.0 % 2, Chebyshev Type 1, (a,b) ((b-x)*(x-a))^(-0.5) % 3, Gegenbauer, (a,b) ((b-x)*(x-a))^alpha % 4, Jacobi, (a,b) (b-x)^alpha*(x-a)^beta % 5, Generalized Laguerre, (a,+oo) (x-a)^alpha*exp(-b*(x-a)) % 6, Generalized Hermite, (-oo,+oo) |x-a|^alpha*exp(-b*(x-a)^2) % 7, Exponential, (a,b) |x-(a+b)/2.0|^alpha % 8, Rational, (a,+oo) (x-a)^alpha*(x+b)^beta % 9, Chebyshev Type 2, (a,b) ((b-x)*(x-a))^(+0.5) % % Input, real ALPHA, the value of Alpha, if needed. % % Input, real BETA, the value of Beta, if needed. % % Output, real T(NT), the knots. % % Output, real WTS(NT), the weights. % parchk ( kind, 2 * nt, alpha, beta ); % % Get the Jacobi matrix and zero-th moment. % [ aj, bj, zemu ] = class_matrix ( kind, nt, alpha, beta ); % % Compute the knots and weights. % [ t, wts ] = sgqf ( nt, aj, bj, zemu ); return end