Mr. Henrik Philipsen 0 Report post Posted July 23, 2015 Dear Caeses crew, I am trying to utilize the Dakota engine to optimize a hull. I use between 2 and 8 design variables, but only one result objective, the total resistance in this case. How do I set the Dakota engine up to search towards the minimum of the result variable?And I am a bit in doubt about how to implement constraints with the design variables. How do I set the limitation scope? Thanks, Henrik Share this post Link to post Share on other sites
Mr. Carsten Fuetterer 9 Report post Posted July 23, 2015 Hello Henrik, did you run a sobol or a sensitivity analysis by dakota first? I would do this to scan the design space. Then you could try the Local Optimization Efficient Algorithm by Dakota. This is a local search with a surrogate model (response surface). It can use the results of the DOE to build a first response surface. It will optimize internaly on this and will calculate the best design and so on. I had some good results when I set the samples per iterations to zero. This means it will calculate just one design of the response surface. But this is just one way to optimize. Does this gives you a first idea? cheers Carsten Share this post Link to post Share on other sites
Mr. Henrik Philipsen 0 Report post Posted July 24, 2015 Hey Carsten, Thanks for your reply. I have done some sensitivity analysis on the variables, and sobol analysis, and I am getting a good mapping of the design space.How does the Dakota Local Optimization Efficient Algorithm know that the objective is to minimize the drag? I have had problems getting it to run. Thanks, Henrik Share this post Link to post Share on other sites
Mr. Carsten Fuetterer 9 Report post Posted July 24, 2015 you just choose the drag as an evaluation and set it as objective. There should be just one objective. cheers Share this post Link to post Share on other sites
Mr. Henrik Philipsen 0 Report post Posted July 24, 2015 And by default it knows it has to minimize the value? Share this post Link to post Share on other sites
Mr. Carsten Fuetterer 9 Report post Posted July 24, 2015 yes, all optimization engines minimize by default. Share this post Link to post Share on other sites
Mr. Henrik Philipsen 0 Report post Posted July 25, 2015 Excellent, thanks Carsten Share this post Link to post Share on other sites
Karsten Wenzke 12 Report post Posted July 27, 2015 Hey Henrik, Don't know if you have already seen it but we released a video for CAESES and Dakota.Here you can watch it. Cheers, Karsten Share this post Link to post Share on other sites
Guest Mr. YEONUK KANG Report post Posted October 27, 2015 hi karstern wenzke I can't find dakota menu in optimization menu. NSGA2,MOSA are my last module in 4.0.2 system. Share this post Link to post Share on other sites
Willy Maschen 1 Report post Posted October 28, 2015 Hallo Mr. Yeonuk Kang, to be able to use the Dakota engine in CAESES an extra licence pack is needed. GreetingsWilly Share this post Link to post Share on other sites
Jörg 29 Report post Posted June 29, 2017 Here is a recent post about surrogate-based optimization with Dakota. Share this post Link to post Share on other sites