Matlab: Call a Matlab function with R values as arguments

In omegahat/RMatlab: R-Matlab interface

Description

These R functions allow one to invoke an arbitrary Matlab function from within R, passing R objects as the arguments to the Matlab function. The two functions are quite different in the model used to invoke the call. .Matlab uses the more akward Engine API for interacting with Matlab. It allows access to Matlab as another process, on a different machine, etc. but uses strings to evaluate the call and uses the Matlab workspace to temporarily store the arguments and results. This has the (small) possibility of overwriting other values within the workspace and causing erroneous results. The .MatlabMexCall is more direct, invoking a function directly without having to store values in the workspace. We can only use this mechanism however when R was originally accessed from within a Matlab session, and not when Matlab was embedded within the R process.

Usage

.Matlab(funcName, ..., .values = list(...), engine, .convert = TRUE, .resultNames = 1)
.MatlabMexCall(funcName, ..., .values = list(...), .nout = 1)

Arguments

funcName	a string giving the name of the Matlab function to invoke
...	the R values that are used as arguments to the Matlab function. These elements can be named or not. Any named elements are assigned to the Matlab workspace and will be available in subsequent calls to .MatlabEval via the specified names. For .MatlabMexCall does not use the names of the arguments.
.values	this is an alternative way to specify the arguments to the Matlab function. This is useful in programmatic (i.e. non-interactive) access to this function where one alread has the arguments in a list.
engine	a MatlabEngine object obtained from .MatlabInit. This is used to identify the particular engine to use, which potentially allows multiple instances of the Matlab engine to be used concurrently, e.g. on different machines
.convert	a logical value indicating whether to convert the result(s) to R objects or leave them as references to Matlab variables. Note that we could (and probably will) just use .resultNames to encode all the possible options of convert or not, or supress all results.
.resultNames	if specified, this can be either a number indicating how many values are expected (since Matlab can return multiple values) or the names of the variables in the Matlab workspace to use for storing the results.
.nout	an integer iving the number of results that are to be returned from the Matlab function. Since Matlab functions can have more than one return value, this is a way to specify in how many we are interested.

Details

Currently, this uses an akward mechanism via the Matlab engine API to evaluate the function call rather than doing it directly in the C code.

Author(s)

Duncan Temple Lang <[e-mail]>

References

Matlab External Interface Guide, the Engine API. Matlab User's Guide

See Also

.MatlabInit .MatlabEval .MatlabGet .MatlabPut

Examples

## Not run: 
  .Matlab('magic', 4)

## End(Not run)

omegahat/RMatlab documentation built on May 24, 2019, 1:54 p.m.