Keywords - Function groups - @ A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

 Library: spatial See also: SPPPinit SPPPinitrandom SPPPsetregion SPPPgetregion SPPPkfn SPPPpsim SPPPssi SPPPkenvl SPPPkaver

 Quantlet: SPPPstrauss Description: simulates a Strauss spatial point process. It uses a spatial birth-and-death process for (4 n) steps (or for (40 n) steps when starting from a binomial pattern on the first call from another function). Note that SPPPinit or SPPPsetregion must have been called before to set the domain. To be able to reproduce results, reset the random number generator for point processes by calling SPPPinitrandom first.

Reference(s):
Venables, W. N., Ripley, B. D. (1999): Modern Applied Statistics with S-Plus, Third Edition, Springer, New York

 Usage: res = SPPPstrauss(nsim, n, c, r) Input: nsim scalar, number of simulations n scalar, number of points in the domain c scalar, in [0, 1]; c = 0 corresponds to complete inhibition at distances up to r r scalar, inhibition distance Output: res list, consisting of components xmat, ymat and type: xmat n x nsim matrix, x coordinates ymat n x nsim matrix, y coordinates type string, "STRAUSS"

Note:
C-Code from Venables, Ripley (1999) forms the basis of this quantlet. Also check this reference for more details.

Example:
```; loads the spatial statistics library
library("spatial")
; reads a spatial data set
; initializes a point process
pinesobj = SPPPinit(pines, 0, 96, 0, 100, 10)
; resets random number generator
SPPPinitrandom(0)
; simulates 100 Strauss point processes(with c = 0.15
; and r = 0.7), each consisting of 72 points,
; in the previously determined domain
ppstrauss = SPPPstrauss(100, 72, 0.15, 0.7)
ppstrauss.xmat[1:3,1:3]
ppstrauss.ymat[1:3,1:3]

```
Result:
```List ppstrauss consists of x and y coordinates of 100 Strauss
point processes, each consisting of 72 points.

Contents of _tmp
[1,]    3.405   4.3925   7.2541
[2,]   6.7804   8.3313   9.1502
[3,]   8.5118    8.757   5.2338

Contents of _tmp
[1,]   4.0346   2.5354   9.0886
[2,]   1.0608   2.3618   6.5437
[3,]    5.603   5.6731   1.4222
```

Author: J. Symanzik, 20000725 license MD*Tech
(C) MD*TECH Method and Data Technologies, 05.02.2006