[![Build Status](https://travis-ci.org/frithnanth/raku-Math-Libgsl-Combination.svg?branch=master)](https://travis-ci.org/frithnanth/raku-Math-Libgsl-Combination) NAME ==== Math::Libgsl::Combination - An interface to libgsl, the Gnu Scientific Library - Combinations. SYNOPSIS ======== ```perl6 use Math::Libgsl::Combination; ``` DESCRIPTION =========== Math::Libgsl::Combination is an interface to the combination functions of libgsl, the Gnu Scientific Library. This package provides both the low-level interface to the C library (Raw) and a more comfortable interface layer for the Raku programmer. ### new(:$n!, :$k!) ### new($n!, $k!) The constructor accepts two parameters: the total number of elements in the set and the number of elements chosen from the set; the parameters can be passed as Pair-s or as single values. The combination object is already initialized in lexicographically first combination, i.e. (0, 1, 2, …, $k − 1). ### init(:$start? = TOP) This method initialize the combination object and returns **self**. The default is to initialize the object in lexicographically first combination, but by specifying the optional parameter **$start** as **BOTTOM** the initialization is performed in the lexicographically last combination, i.e. ($n − $k, $n − $k + 1, …, $n − 1). TOP and BOTTOM are declared as values of the Starting-point enum. ### copy($src! where * ~~ Math::Libgsl::Combination) This method copies the combination **$src** into the current combination object and returns **self**. ### get(Int $elem! --> Int) This method returns the combination value at position **$elem**. ### all(--> Seq) This method returns a Seq of all the elements of the current combination. ### size(--> List) This method returns the (n, k) parameters of the current combination object. ### is-valid(--> Bool) This method checks whether the current combination is valid: the k elements should lie in the range 0 to $n − 1, with each value occurring once at most and in increasing order. ### next() ### prev() These functions advance or step backwards the combination and return **self**, useful for method chaining. ### bnext(--> Bool) ### bprev(--> Bool) These functions advance or step backwards the combination and return a Bool: **True** if successful or **False** if there's no more permutation to produce. ### write(Str $filename! --> Int) This method writes the combination data to a file. ### read(Str $filename! --> Int) This method reads the combination data from a file. The combination must be of the same size of the one to be read. ### fprintf(Str $filename!, Str $format! --> Int) This method writes the combination data to a file, using the format specifier. ### fscanf(Str $filename!) This method reads the combination data from a file. The combination must be of the same size of the one to be read. C Library Documentation ======================= For more details on libgsl see [https://www.gnu.org/software/gsl/](https://www.gnu.org/software/gsl/). The excellent C Library manual is available here [https://www.gnu.org/software/gsl/doc/html/index.html](https://www.gnu.org/software/gsl/doc/html/index.html), or here [https://www.gnu.org/software/gsl/doc/latex/gsl-ref.pdf](https://www.gnu.org/software/gsl/doc/latex/gsl-ref.pdf) in PDF format. Prerequisites ============= This module requires the libgsl library to be installed. Please follow the instructions below based on your platform: Debian Linux ------------ sudo apt install libgsl23 libgsl-dev libgslcblas0 That command will install libgslcblas0 as well, since it's used by the GSL. Ubuntu 18.04 ------------ libgsl23 and libgslcblas0 have a missing symbol on Ubuntu 18.04. I solved the issue installing the Debian Buster version of those three libraries: * [http://http.us.debian.org/debian/pool/main/g/gsl/libgslcblas0_2.5+dfsg-6_amd64.deb](http://http.us.debian.org/debian/pool/main/g/gsl/libgslcblas0_2.5+dfsg-6_amd64.deb) * [http://http.us.debian.org/debian/pool/main/g/gsl/libgsl23_2.5+dfsg-6_amd64.deb](http://http.us.debian.org/debian/pool/main/g/gsl/libgsl23_2.5+dfsg-6_amd64.deb) * [http://http.us.debian.org/debian/pool/main/g/gsl/libgsl-dev_2.5+dfsg-6_amd64.deb](http://http.us.debian.org/debian/pool/main/g/gsl/libgsl-dev_2.5+dfsg-6_amd64.deb) Installation ============ To install it using zef (a module management tool): $ zef install Math::Libgsl::Combination AUTHOR ====== Fernando Santagata COPYRIGHT AND LICENSE ===================== Copyright 2020 Fernando Santagata This library is free software; you can redistribute it and/or modify it under the Artistic License 2.0.