RELEASE NOTES 

		spatstat 1.9-1

	 	26 May 2006

We thank Rasmus Waagepetersen for substantial contributions of new code,
and Colin Beale and Malte Spiess for suggestions.

OVERVIEW

	New functions for fitting point process models 
	by the Method of Minimum Contrast. 

	Fast code for the K function (Kest and Kinhom)
	can now handle huge point patterns.

	More support for line segments and polygons.
	
NEW FUNCTIONS


	thomas.estK
	matclust.estK
	lgcp.estK
		New algorithms for model-fitting, 
		kindly supplied by Rasmus Waagepetersen.
		Fit a Thomas model, Matern Cluster model, or 
		log-Gaussian Cox point process model to a point pattern
		using the Method of Minimum Contrast.

	mincontrast
		General algorithm for the Method of Minimum Contrast,
		kindly supplied by Rasmus Waagepetersen.
	
	crossing.psp
	selfcrossing.psp
		Find crossing-points between two line segment patterns,
		or self-crossing points in a line segment pattern.



IMPROVEMENTS/ENHANCEMENTS

	Kest, Kinhom
		Modified to handle very large point pattern datasets. 

		A fast algorithm for computing the border correction, 
		in an arbitrary window, has been written in C. 
		This algorithm can handle a point pattern of any size,
		up to the maximum size of an object in R. 
		We have tested it on patterns of 1,000,000 points
		with computation times of about 1 minute per 100,000 points.

		When the number of points exceeds a threshold 'nlarge',
		Kest/Kinhom now switches to this fast algorithm (and therefore
		only computes the border correction) by default. 

	rmh
		Code has been slightly accelerated;
		simulation times have dropped by 2-10% 
		depending on the model.

	ppm
		The test for validity of covariates is now applied
		only to those covariates that are actually named
		in the model formula.

	owin
		Polygonal windows are now checked more carefully,
		including checks for 
			- duplicated vertices
			- self-intersection of polygons
			- intersection between different polygons
		
	data(letterR)
		Modified (the data contained a repeated vertex!)

	Documentation 
		help files improved.

	rMaternI
	rMaternII
	rNeymanScott
	rMatClust
		changed 'lambda' to 'kappa' in these functions,
		for conformity with the new minimum contrast functions.

WARNINGS

	Kest		
		The argument sequence of Kest has been altered. The default
		vector of r values in Kest has been altered.

BUGS

	none (this week!)