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 SPPPstrauss SPPPkenvl SPPPkaver

 Quantlet: SPPPssi Description: simulates a SSI (sequential spatial inhibition) point process. 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. Note that this quantlet will not return a result if r is too large and if it is impossible to place n points.

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

 Usage: res = SPPPssi(nsim, n, r) Input: nsim scalar, number of simulations n scalar, number of points in the domain r scalar, inhibition distance Output: res list, consisting of components xmat, ymat and type: res.xmat n x nsim matrix, x coordinates res.ymat n x nsim matrix, y coordinates res.type string, "SSI"

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 SSI point processes(with r = 0.7),
; each consisting of 72 points, in the previously
; determined domain
ppssi = SPPPssi(100, 72, 0.7)
ppssi.xmat[1:3,1:3]
ppssi.ymat[1:3,1:3]

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

Contents of _tmp
[1,]  1.0709e-06   7.7566   8.5364
[2,]   1.1978   5.9195   1.6666
[3,]  0.034049  0.67031   7.4771

Contents of _tmp
[1,]  0.030269   9.6169   0.1943
[2,]   4.2072   0.2853  0.88153
[3,]   2.3159   4.7711   0.9613
```

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