# lapvf, lapvg

Given vector quantity (u,v), compute the vector Laplacian via Spherepack.

## Synopsis

```    procedure lapvf(
u    : float,
v    : float,
ulap : float,
vlap : float
)

procedure lapvg(
u    : float,
v    : float,
ulap : float,
vlap : float
)
```

## Arguments

u, v
vector field arrays (input, two or more dimensions, last two dimensions must be nlat x nlon and input values must be in ascending latitude order)
ulap, vlap
vector Laplacian arrays (output, same dimensions as u, v, values will be in ascending latitude order)

## Description

Given vector field u and v, lapvf and lapvg both compute the Laplacian vector and return the results in the arrays ulap and vlap. lapvf operates on an equal (fixed) grid, and lapvg 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)

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