Utilities and shorthands

Topics covered in this section:

This section lists several drivers that can be used from the Mosel libraries and also within Mosel models. These drivers are described in the `Mosel Language Reference Manual'.

tmp: accessing the temporary directory of Mosel

The driver tmp is an extension to the default driver that locates the specified file in the temporary directory used by Mosel. For example, we might wish to compile a submodel file to a BIM file located in the temporary directory:

if compile("", "burglar.mos", "tmp:burglar.bim")<>0 then exit(1); end-if
load(modBurg, "tmp:burglar.bim")     ! Load the BIM file 

The same can be achieved with the following library commands (Mosel C libraries):

XPRMcompmod(NULL, "burglar.mos", "tmp:burglar.bim", "Burglar example");
mod = XPRMloadmod("tmp:burglar.bim",NULL);     /* Load the BIM file */

The tmp driver can also be used with the library interfaces to other programming languages, such as the Mosel Java library:

  mosel.compile("", "burglar2.mos", "tmp:burglar2.bim", "");
  mod = mosel.loadModel("tmp:burglar2.bim");

Mosel's temporary directory is located in the system temporary directory, its actual definition depends on the system that is used for running Mosel and can be retrieved via the Mosel function getparam.

writeln("Temporary directory: ", getparam("tmpdir") )

tee: multiple output destinations

The tee driver duplicates output into up to 6 files simultaneously. It is particularly useful for creating output log files while still being able to watch progress output on screen. If we wish to maintain screen display and at the same time log the output in the file burglarsol.txt for the example burglar2ff.mos from Section Alternative text data file formats we may use the following Mosel code:

 fopen("tee:burglarsol.txt&", F_OUTPUT+F_APPEND)
 writeln("Solution:\n Objective: ", getobjval)
 forall(i in ITEMS)  writeln(" take(", i, "): ", getsol(take(i)))
 fclose(F_OUTPUT)

The tee driver also works with the library functions, such as to duplicate all the output generated by a model (output to a file and on screen, Mosel C libraries):

XPRMsetdefstream(mod, XPRM_F_WRITE, "tee:burglarlog.txt&");

Analogously with other library interfaces, such as the Mosel Java library:

mod.setDefaultStream(XPRM.F_OUTPUT, "tee:burglarlog.txt&");

null: disactivating a stream

The typical use of the null driver is to make (embedded) models silent by disabling their output, either from the host application embedding the model 'mod' (Mosel C libraries):

XPRMsetdefstream(mod, XPRM_F_WRITE, "null:");

Similarly with other library interfaces, such as with the Mosel Java library:

mod.setDefaultStream(XPRM.F_OUTPUT, "null:");

Or from within Mosel, such as in a model that controls the execution of a submodel 'submod':

setdefstream(submod, F_OUTPUT, "null:")

Or even directly in the (sub)model itself:

fopen(F_OUTPUT, "null:")