# fdweights.m

From Spinach Documentation Wiki

Calculates finite difference weights for numerical derivatives, including order 0, which amounts to interpolation.

## Contents

## Syntax

w=fdweights(target_point,grid_points,max_order)

## Arguments

target_point - the point at which the derivative is required grid_points - the points at which the function is given max_order - maximum derivative order

## Outputs

w - finite difference coefficient array with the coefficients for the succes- sive derivatives in rows

## Examples

Point weights for central schemes on a three-point stencil, where the value is required at the centre:

>> fdweights(0,[-1 0 1],2) ans = 0 1.0000 0 -0.5000 0 0.5000 1.0000 -2.0000 1.0000

The three rows are for interpolation, first derivative and second derivative respectively.

## See also

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

*Version 2.2, authors: Bengt Fornberg, Ilya Kuprov*