# wrappers

##### Wrappers for the C functions used in geoR

These functions are *wrappers* for some (but not all)
the C functions
included in the geoR package.
Typically the C code is directly called from the geoR
functions but these functions allows independent calls.

- Keywords
- spatial, programming, interface

##### Usage

```
diffpairs(coords, data)
loccoords(coords, locations)
.diagquadraticformXAX(X, lowerA, diagA)
.bilinearformXAY(X, lowerA, diagA, Y)
.corr.diaglowertri(coords, cov.model, phi, kappa)
.Ccor.spatial(x, phi, kappa, cov.model)
```

##### Arguments

- coords
an \(n \times 2\) matrix with the data coordinates.

- data
an vector with the data values.

- locations
an \(N \times 2\) matrix with the coordinates of the prediction locations.

- lowerA
a vector with the diagonal terms of the symmetric matrix A.

- diagA
a vector with the diagonal terms of the symmetric matrix A.

- X
a matrix with conforming dimensions.

- Y
a matrix with conforming dimensions.

- cov.model
covariance model, see

`cov.spatial`

for options and more details.- phi
numerical value of the correlation function parameter phi.

- kappa
numerical value of the correlation function parameter kappa.

- x
a vector of distances.

##### Value

The outputs for the different functions are:

returns a list with elements `dist`

- the
distance between pairs of points, and `diff`

- the difference
between the values of the attributes.

returns a \(n \times N\) matrix with distances between data points and prediction locations.

returns a vector with the diagonal term of the quadratic form \(X' A X\).

returns a vector or a matrix with the terms of the quadratic form \(X' A Y\).

returns the lower triangle of the correlation matrix, including the diagonal.

returns a vector of values of spatial correlations.

##### References

Further information on the package geoR can be found at: http://www.leg.ufpr.br/geoR.

*Documentation reproduced from package geoR, version 1.8-1, License: GPL (>= 2)*