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DDT

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Description Content
module load devel/ddt
Availability bwUniCluster | BwForCluster_Chemistry
License Floating or server locked licences for developers and users. | Allinea DDT licensing
Citing n/a
Links Alinea DDT Homepage
Graphical Interface Yes


1 Introduction

Allinea DDT: The debugger for C, C++ and F90 threaded and parallel code.
Allinea DDT's powerful intuitive GUI defines the standard of multi-process, multi-threaded debugging. Zero-click variable comparisons and powerful array visualizations simplify the complexity of debugging software wriitten to exploit today's increasingly parallel processors, clusters and supercomputers.

DDT consists of a graphical front end and a back end serial debugger which controls the application program. One instance of the serial debugger controls one MPI process. Via the fron tend the user interacts with the debugger to select the program that will be debugged, to specify different options and to monitor the execution of the program. Debugging commands may be sent to one, all or a subset of the MPI processes.

See more infos about DDT

2 Versions and Availability

A list of versions currently available on all bwHPC-C5-Clusters can be obtained from the

Cluster Information System CIS

On the command line interface of any bwHPC cluster you'll get a list of available versions by using the command
'module avail devel/ddt'.

$ : bwUniCluster
$ module avail devel/ddt
------------------------ /opt/bwhpc/common/modulefiles -------------------------
devel/ddt/4.2.1 devel/ddt/5.0.1


3 Loading

Now, the DDT-GUI may be started with the command
'ddt [program-name] &'.
[program-name] is the name of your program that you want to debug.

3.1 GUI

This is the DDT’s startup window.
Before actually starting the debugging session, you should check the contents of several fields in this window.

Ddt1 750.jpg

  1. The top line shows the executable file that will be run under control of the debugger. In the following lines you may input some options that are passed to your program or to the MPI environment.
  2. If your program reads data from stdin you can specify an input file in the startup window.
  3. Before starting an MPI program you should check that "Open MPI (Compatability)" or "Intel MPI" is the MPI implementation that has been selected. If this is not the case, you have to change this. Otherwise ddt may not be able to run your program. In order to debug serial programs, the selected MPI implementation should be "none". You may also change the underlying serial debugger using the "change" button. By default ddt uses its own serial debugger, but it may also use the Intel idb ebugger.
  4. Select the number of MPI processes that will be started by ddt. If you are using ddt within a batch job, replace mpirun by ddt in the command line of ????? and make sure that the chosen number of MPI processes is identical to the number of MPI tasks (-p option ???) that you selected with the ?????? command. When you debug a serial program, select 1.
  5. After you have checked all inputs in the ddt startup window, you can start the debugging session by pressing the "run" button.


The ddt window now shows the source code of the program that is being debugged and breakpoints can be set by just pointing to the corresponding line and pressing the right mouse button.
So you may step through your program, display the values of variables and arrays and look at the message queues.

Ddt2 750.jpg