# lapsf, lapsg

Given a scalar z, compute its Laplacian via Spherepack.

## Synopsis

procedure lapsf(
z : float,
zlap : float
)
procedure lapsg(
z : float,
zlap : float
)

## Arguments

*z*
- scalar function array (input, two or more dimensions, last two
dimensions must be
*nlat* x *nlon* and input values must be
in ascending latitude order).
*zlap*
- Laplacian array (output, same dimensions as
*z*, values will
be in ascending latitude order)

## Description

*lapsf* and *lapsg* both compute the Laplacian
*z* and return it in the array *zlap*. *lapsf*
operates on an equal (fixed) grid, and *lapsg* operates on a
Gaussian grid.
**Note**: For the arrays whose last two dimensions are *nlat*
x *nlon*, the rest of the dimensions (if any) are collectively
referred to as *nt*. If the input/output arrays are just two
dimensions, then *nt* can either be considered equal to 1 or
nothing at all.

Arrays which have dimensions *nt* x *nlat* x *nlon*
should **not** include the cyclic (wraparound) points when invoking
the procedures and functions which use spherical harmonics
(Spherepack).

For example, if an array *x* has dimensions *nlat* = 64 and
*nlon* = 129, where the "129" represents the cyclic points, then
the user should pass the data to the procedure/function via:

z = sample ( x([...],:,0:nlon-2) ) ; does not include cyclic points

## Error messages

If *jer* or *ker* is equal to:
1 : error in the specification of *nlat*

2 : error in the specification of *nlon*

4 : error in the specification of *nt* (*jer* only)

### Reference Manual Control Panel

NG4.1 Home, Index, Examples, Glossary, Feedback, Ref Contents, Ref WhereAmI?

* $Revision: 1.8 $ $Date: 1999/02/23 15:59:25 $ *