intro story Coast / Estuary

Coast / Estuary

Coastal systems are among the most dynamic physical systems on earth and are subject to a large variety of forces. The morphodynamic changes occurring to coastlines worldwide are of great interest and importance. These changes occur as a result of the erosion of sediments, its subsequent transport as bed load or suspended load, and eventual deposition. 
 
Estuaries are partly enclosed water bodies that have an open connection to the coast. Estuaries generally have one or more branching channels, intertidal mudflats and/or salt marshes. Intertidal areas are of high ecological importance and trap sediments (sands, silts, clays and organic matter).
Within the Delft3D modelling package a large variation of coastal and estuarine physical and chemical processes can be simulated. These include waves, tidal propagation, wind- or wave-induced water level setup, flow induced by salinity or temperature gradients, sand and mud transport, water quality and changing bathymetry (morphology). Delft3D can also be used operationally e.g. storm, surge and algal bloom forecasting. 
 
On this discussion page you can post questions, research discussions or just share your experience about modelling coastal and/or estuarine systems with Delft3D FM. 
 

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Sub groups
D-Flow Flexible Mesh
DELWAQ
Cohesive sediments & muddy systems

 

 

Message Boards

Error Delwaq2 by increasing the number of Processors

GS
Gholamreza Shiravani, modified 2 Years ago.

Error Delwaq2 by increasing the number of Processors

Padawan Posts: 65 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?

MJ
Michelle Jeuken, modified 2 Years ago.

RE: Error Delwaq2 by increasing the number of Processors

Jedi Knight Posts: 154 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 Years ago.

RE: Error Delwaq2 by increasing the number of Processors

Padawan Posts: 65 Join Date: 6/25/16 Recent Posts

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