# fdlap.m

From Spinach Documentation Wiki

Returns a finite-difference representation of the Laplacian for an array with a user-specified finite difference stencil size. The resulting operator is a sparse matrix designed to act on the vectorisation of the array. The dimensions of the array are assumed to be ordered as [X Y Z].

## Contents

## Syntax

L=fdlap(npoints,extents,nstenc)

## Arguments

dims - a one-element, two-element, or three-element vector specifying the number of discretisation points in each dimension of the 1D, 2D, or 3D array of data that the operator will be acting on, ordered as [X Y Z]. extents - a one-element, two-element, or three-element vector specifying the size of each dimension of the array, ordered as [X Y Z]. nstenc - number of finite-difference stencil points for the finite-difference approximation; periodic boundary conditions are used

## Outputs

L - a sparse matrix designed to act on the vectori- zation of the 3D array. The dimensions of that array are assumed to be ordered as [X Y Z].

## See also

fdvec.m, fdmat.m, fdhess.m, fdkup.m, fdweights.m, fftdiff.m, fourdif.m, fourlap.m

*Version 2.2, authors: Ilya Kuprov*