Help page for addreg.find 
 	
	Find a cumulative additive regression estimate in survival analysis

DESCRIPTION:

	Function that finds an additive regression estimate in survival analysis,
        	and returns data with estimates, variances of estimates and the
	relevant survival times.

USAGE:
	addreg.find(covar, trisk, status,stoptime,stopcond,stand,na.rm)

REQUIRED ARGUMENTS:

covar
	This variable contains the covariates of the analysis,
	with one row for each subject 

trisk
	Observation times.

status
	Status is 0 if the observation is censored, and 1 otherwise.

OPTIONAL ARGUMENTS:

stoptime
	Here you can select the time for which you want the estimation
	to stop. If you don't select any time the routine continues until
	YY’ becomes singular 

stopcond
	This is the test value for the rank of the matrix. Is’s numeric and can fail for very small covariates. In this case one could adjust the variable "stoptime" to some lager number, but if you choose it to big, it will not let the estimates go so far in time as they could. Default value is 0.001

stand
If  "stand" is true the covariat are standardised, that is, the mean is subtracted from each covarite . Default is true.	

na.rm
If "na.rm" is true all observations with missing values are ignored. Default is true.

 VALUE:
	The function returns a three dimensional array with:
	
	First element 1: 
	Is 1 for estimates of expectation and 2 for estimates of variances.
	
	Second elements:
	Number 1 is the times of estimates, then comes the constant, 
	covariate number 1, covariate number 2 ...
	
	Last element:
	Is the observation number

	Remark: Normally the data are read by the function "addreg.show" or "addreg.est",
	so that the user does not need to know anything about the data structure (see example).

SIDE EFFECTS:
	None

DETAILS:
	The routine makes notes when YY’ becomes singular and the estimation stops.
	
REFERENCES:
	Note on use is distributed with the package
        	("Documentation for S-plus package in additive survival analysis")	     
	
	See also internet:    	http://www.med.uio.no/imb/stat/addreg/  
	Procedure written by:	Harald Fekjaer, e-mail: hfe@math.uio.no 
	Theoretical work by:	Prof. Odd O. Aalen
	Research institute:	Section of Medical Statistics, University of Oslo, Norway 
	Date:               	1997 

WARNING as needed:
	THIS FUNCTION IS FREE AND COMES WITH ABSOLUTELY NO
 	WARRANTY, WHETHER FOR THE METHOD OR IT’S IMPLEMENTATION. 
	
	The routine that tests the rank of matrix is numeric, and can fail for very small covariate values. In this case one could adjust the variable "stoptime"

	Please report to Harald Fekjaer (E-mail: hfe@math.uio.no) if you 
	find any weaknesses or have any ideas on how to improve the program.

SEE ALSO:
	addreg.show , addreg.est , addreg.test, addreg

EXAMPLES:
To find and display results use:
> res <- addreg.find(covar, trisk, status)
> addreg.show(res)