CallMatlab: Function that executes Matlab code

In jacobbien/CVXfromR: Matlab and CVX from R

Description

Given a string of Matlab code, a list of inputs, and a vector of names of output variables, this function opens Matlab, runs the Matlab code, closes Matlab, and then returns all the output variables. This function assumes that Matlab can be called from the command line using "matlab" (or more generally the string given in the argument matlab.call)

Usage

CallMatlab(matlab.code, inputs = list(), output.names = NULL, delete.temp = TRUE, norun = FALSE, matlab.call = "matlab")

Arguments

matlab.code	A string containing Matlab code. Use semicolons to separate lines. This function assumes that the Matlab code is valid. The names of variables used in this string should match those in the inputs argument.
inputs	List containing all variables that need to be passed to Matlab. The names of the elements of the list should match the names used in matlab.code. All variables must be numeric (e.g. matrices, vectors, scalars)
output.names	Array of names of all variables that should be returned from Matlab. The names should match those used in matlab.code. All variables must be numeric (no strings).
delete.temp	Default TRUE. Indicates whether the temporary files that are created should be deleted.
norun	Default FALSE. Mostly for debugging purposes. Returns the command that would be run in Matlab without it actually opening Matlab.
matlab.call	How Matlab can be invoked through the "system" command. Default: "matlab" but even if this is the alias in your default shell, "system" might use a different shell in which "matlab" is not recognized.

Details

This function is pretty low-tech but works well. It begins by writing every variable in inputs to a separate text file named temp_in_<variablename>.txt. A Matlab expression is then formed that does the following:

1) reads in each of the input files; 2) executes matlab.code; 3) writes each output variable to a file named temp_out_<variablename>.txt.

CallMatlab uses the R function "system" to call Matlab from the command line. Finally, R reads in each output file and deletes all the files that were created (if delete.temp==TRUE).

Value

A list containing all the outputs that were listed in output.names with the values they have after matlab.code was executed in Matlab.

command

The string that is run on the command line.

Author(s)

Jacob Bien

Examples

# 1) example of basic usage
x <- rnorm(100)
y <- 1:100
inputs <- list(x=x, y=y)
## Not run: 
out <- CallMatlab("z=x+y", inputs, "z")
out2 <- CallMatlab("z=x+y;x=x+1", inputs, c("z","x"))

## End(Not run)

# 2) example where there are no input variables
## Not run: 
CallMatlab("I = eye(100)", output.names="I")

## End(Not run)

jacobbien/CVXfromR documentation built on May 18, 2019, 8:01 a.m.