npRmpi (version 0.60-20)

gradients: Extract Gradients

Description

gradients is a generic function which extracts gradients from objects.

Usage

gradients(x, ...)
# S3 method for condensity
gradients(x, errors = FALSE, ...)
# S3 method for condistribution
gradients(x, errors = FALSE, ...)
# S3 method for npregression
gradients(x, errors = FALSE, ...)
# S3 method for qregression
gradients(x, errors = FALSE, ...)
# S3 method for singleindex
gradients(x, errors = FALSE, ...)

Value

Gradients extracted from the model object x.

Arguments

x

an object for which the extraction of gradients is meaningful.

...

other arguments.

errors

a logical value specifying whether or not standard errors of gradients are desired. Defaults to FALSE.

Author

Tristen Hayfield , Jeffrey S. Racine

Details

This function provides a generic interface for extraction of gradients from objects.

References

See the references for the method being interrogated via gradients in the appropriate help file. For example, for the particulars of the gradients for nonparametric regression see the references in npreg

See Also

fitted, residuals, coef, and se, for related methods; npRmpi for supported objects.

Examples

if (FALSE) {
## Not run in checks: excluded to keep MPI examples stable and check times short.
## The following example is adapted for interactive parallel execution
## in R. Here we spawn 1 slave so that there will be two compute nodes
## (master and slave).  Kindly see the batch examples in the demos
## directory (npRmpi/demos) and study them carefully. Also kindly see
## the more extensive examples in the np package itself. See the npRmpi
## vignette for further details on running parallel np programs via
## vignette("npRmpi",package="npRmpi").

## Start npRmpi for interactive execution. If slaves are already running and
## `options(npRmpi.reuse.slaves=TRUE)` (default on some systems), this will
## reuse the existing pool instead of respawning. To change the number of
## slaves, call `npRmpi.stop(force=TRUE)` then restart.
npRmpi.start(nslaves=1)

set.seed(42)

x <- runif(10)
y <- x + rnorm(10, sd = 0.1)
mydat <- data.frame(x,y)
rm(x,y)

mpi.bcast.Robj2slave(mydat)

mpi.bcast.cmd(model <- npreg(y~x, data=mydat, gradients=TRUE),
              caller.execute=TRUE)

gradients(model)

## For the interactive run only we close the slaves perhaps to proceed
## with other examples and so forth. This is redundant in batch mode.

## Note: on some systems (notably macOS+MPICH), repeatedly spawning and
## tearing down slaves in the same R session can lead to hangs/crashes.
## npRmpi may therefore keep slave daemons alive by default and
## `npRmpi.stop()` performs a "soft close". Use `force=TRUE` to
## actually shut down the slaves.
##
## You can disable reuse via `options(npRmpi.reuse.slaves=FALSE)` or by
## setting the environment variable `NP_RMPI_NO_REUSE_SLAVES=1` before
## loading the package.

npRmpi.stop()               ## soft close (may keep slaves alive)
## npRmpi.stop(force=TRUE)  ## hard close

## Note that in order to exit npRmpi properly avoid quit(), and instead
## use mpi.quit() as follows.

## mpi.bcast.cmd(mpi.quit(),
##               caller.execute=TRUE)
}