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DELWAQ

DELWAQ is the engine of the D-Water Quality and D-Ecology programmes of the Delft3D suite. It is based on a rich library from which relevant substances and processes can be selected to quickly put water and sediment quality models together.

The processes library covers many aspects of water quality and ecology, from basic tracers, dissolved oxygen, nutrients, organic matter, inorganic suspended matter, heavy metals, bacteria and organic micro-pollutants, to complex algae and macrophyte dynamics. High performance solvers enable the simulation of long periods, often required to capture the full cycles of the processes being modelled.

The finite volume approach underlying DELWAQ allows it to be coupled to both the structured grid hydrodynamics of the current Delft3D-FLOW engine and the upcoming D-Flow Flexible Mesh engine (1D-2D-3D) of the Delft3D Flexible Mesh Suite (or even other models such as TELEMAC).

'DELWAQ in open source' is our invitation to all leading experts to collaborate in further development and research in the field of water quality, ecology and morphology using Delft3D. Feel free to post your DELWAQ related questions or comments in this dedicated forum space. If you are new to DELWAQ, the tutorial (in the user manual) is a good place to start. A list of DELWAQ related publications is available here.

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D-Flow Flexible Mesh
DELWAQ

Cohesive sediments & muddy systems

 


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Error Delwaq2 by increasing the number of Processors

GS
Gholamreza Shiravani, modified 2 Months ago.

Error Delwaq2 by increasing the number of Processors

Youngling Posts: 13 Join Date: 6/25/16 Recent Posts

Hi,

I want to run delwaq2 on 28 processors. I used the nothreads command to manage the computations. When I use -nothreads 1 it runs fine, without errors. When I use -nothreads 2 or 3 it runs fine, with some warnings but the Simulation is not crashed. Using 4 and more processors the simulation will be crashed. I attached the simulation files from 1,2,3 and 4 processors. Could you tell me how can I solve this Problem?

Michelle Jeuken, modified 2 Months ago.

RE: Error Delwaq2 by increasing the number of Processors

Jedi Knight Posts: 156 Join Date: 1/21/13 Recent Posts

Hm, seems like you are running multiple instances of Delwaq at once. This is not how is parallelism in Delwaq works. Delwaq uses OpenMP parallelisation, so only one instance of Delwaq should be running on one node, which could use multiple threads. Seen from your screen dump you have an extra tool to launch multiple Delwaq's on 4 nodes. They will all try to write the same files, so this will crash...

It might be that the command line option -nothreads also trigers the multiple instances of Delwaq. It is best to set the number of threads in the input file of Delwaq itself in block 7 (which is terminated by #7) through the special constant nothreads. Like this:
 

 

CONSTANTS nothreads DATA 0.0


You can either set it to 0 (max number of threads) or to the number of threads you want. No command line argument is needed then.

If you need more info, look in the Input File Description manual (section 7.3.1.1).

 

Michelle

GS
Gholamreza Shiravani, modified 2 Months ago.

RE: Error Delwaq2 by increasing the number of Processors

Youngling Posts: 13 Join Date: 6/25/16 Recent Posts

Hi Michelle, thanks a lot. Now it works fine.