toms655, a Python code which computes weights for interpolatory quadrature schemes, by Sylvan Elhay and Jaroslav Kautsky.
Only a small part of this code has been converted to Python!
Thus, the typical use of this code is for the user to specify a quadrature interval, a weight function, and a sequence of abscissas (which may be repeated), and to request the corresponding weight vector so that an interpolatory quadrature rule is produced.
Note that when an abscissa is repeated, this indicates that, at this point, not only the function value but one or more derivatives are to be used in the quadrature formula.
The code is also suitable for the simpler task of computing both the abscissas and weights for a variety of classical Gaussian quadrature rules, including
Name | Interval | Weight function |
---|---|---|
Legendre | (a,b) | 1.0 |
Chebyshev Type 1 | (a,b) | ((b-x)*(x-a))^(-0.5) |
Gegenbauer | (a,b) | ((b-x)*(x-a))^alpha |
Jacobi | (a,b) | (b-x)^alpha*(x-a)^beta |
Laguerre and Generalized Laguerre | (a,+oo) | (x-a)^alpha*exp(-b*(x-a)) |
Hermite and Generalized Hermite | (-oo,+oo) | |x-a|^alpha*exp(-b*(x-a)^2) |
Exponential | (a,b) | |x-(a+b)/2.0|^alpha |
Rational | (a,+oo) | (x-a)^alpha*(x+b)^beta |
The text of many ACM TOMS algorithms is available online through ACM: https://calgo.acm.org/ or NETLIB: https://www.netlib.org/toms/index.html.
The computer code and data files made available on this web page are distributed under the GNU LGPL license.
toms655 is available in a C version and a C++ version and a Fortran90 version and a MATLAB version and an Octave version and a Python version.