Sparse Grids ------------- Implementation of Sparse Grid (Smolyak) methods for numerical integration. This implementation is a porting of the Sparse-Grid package developped in MatLab(R) at http://www.sparse-grids.de The code is extended with Clenshaw-Curtis and Fejer quadrature rules [1] @copyright: 2007 Florian Heiss, Viktor Winschel @copyright: 2012-2015 Daniele Bigoni .. [1]: Waldvogel, J. (2006). Fast Construction of the Fejér and Clenshaw–Curtis Quadrature Rules. Bit Numerical Mathematics, 46(1), 195–202. doi:10.1007/s10543-006-0045-4