Description Usage Arguments Details Value Author(s) References Examples
These functions are the main interface functions for calculating Nearlyisotonic solutions
1 2 3  neariso(y, maxBreaks=100, lambda=NULL)
nearisoGetBreakpoints(nearisoPathObj, maxBreaks=100)
nearisoGetSolution(nearisoPathObj, lambda=nearisoGetBreakpoints(nearisoPathObj))

y 
response variable; numeric 
lambda 
penalty parameter vector (nonnegative) for the difference of coefficients; numeric 
nearisoPathObj 
Solution object of class 
maxBreaks 
maximum number of breakpoints the function should return 
neariso
is the main function to calculate a Nearlyisotonic regression fit and returns an object of class nearisoPath
. If lambda=NULL, then the breakpoints of the linear solution path of beta are chosen, however at most maxBreaks
. See nirGetBreakpoints
for what happens if there are more than maxBreaks
breakpoints.
nearisoGetSolution
takes an object of class nearisoPath
and returns an object of the same class, but with the solution calculated for the given value of lambda
. Advantage in comparison to neariso
is that it uses the already calculated solution and does not recompute the entire solution path, therefore being faster.
nearisoGetBreakpoints
returns the lambda values at which the piecewise linear solution paths for beta have a breakpoint. If there are more than maxBreaks
such breakpoints, only maxBreaks
representative breakpoints will be returned, including the first and last.
Returns a list with the items
solObj 
Object of class 
lambda 
Values of 
df 
Number of different values for beta in the solution; degrees of freedom; same length as 
beta 

Holger Hoefling
Ryan Tibshirani, Holger Hoefling, Rob Tibshirani. Nearlyisotonic regression. 2010. To appear in Technometrics.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18  library(neariso)
# generate some artificial data
y < rnorm(1000) + (1:1000)/3000
### run the algorithm as default; will output solution at 100 breakpoints for lambda
res0 < neariso(y)
### apply function nir and get solution directly
lambda = 0:10/10
res < neariso(y, lambda=lambda)
### apply the function and get the solution later
res2 < neariso(y, lambda=NULL)
res2 < nearisoGetSolution(res2, lambda=lambda)
### look at the breakpoints
lambdaBreaks < nearisoGetBreakpoints(res2, maxBreaks=1000)
res3 < nearisoGetSolution(res2, lambda=lambdaBreaks)

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