Hello Debadrita Paria
                            
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                                                Posted:
                            
                                1 decade ago                            
                            
                                2014/09/23 23:11 GMT-4                            
                        
                        
                                                    Please try the direct solver instead of the iterative solver. I had exactly the same problem (extremely slow convergence at about 360 nm for a silver nanocrystal), and the direct solver worked perfectly.                                                
                                                
                            Please try the direct solver instead of the iterative solver. I had exactly the same problem (extremely slow convergence at about 360 nm for a silver nanocrystal), and the direct solver worked perfectly.                        
                                                
                                                                                                            
                                             
                                            
                                                
    
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                                                Posted:
                            
                                9 years ago                            
                            
                                2017/01/20 11:10 GMT-5                            
                        
                        
                                                    I was stuck in same problem.
Thanks for your comment. !                                                
                                                
                            I was stuck in same problem.
Thanks for your comment. !                        
                                                
                                                                                                            
                                             
                        
                        
                            
                                                                                        
                                Walter Frei
                                                                                                                                                    COMSOL Employee
                                                         
                            
                                                                                                                                                
                         
                                                
    
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                                                Posted:
                            
                                9 years ago                            
                            
                                2017/01/20 11:44 GMT-5                            
                        
                        
                                                    Hello All,
Having to use a direct solver is also often a sign that you've undermeshed the problem, especially in the silver material domains. 
If you're dealing with a model that has lossy materials, please read:
www.comsol.com/blogs/modeling-of-materials-in-wave-electromagnetics-problems/
www.comsol.com/blogs/simulation-tools-for-solving-wave-electromagnetics-problems/
Meshing more finely may improve solution speed when using the iterative solver (and although a more finely meshed problem will use more memory, the iterative solver uses much less memory that the direct solver, so you generally come out ahead.) 
Best Regards,
                                                
                            Hello All,
Having to use a direct solver is also often a sign that you've undermeshed the problem, especially in the silver material domains. 
If you're dealing with a model that has lossy materials, please read:
https://www.comsol.com/blogs/modeling-of-materials-in-wave-electromagnetics-problems/
https://www.comsol.com/blogs/simulation-tools-for-solving-wave-electromagnetics-problems/
Meshing more finely may improve solution speed when using the iterative solver (and although a more finely meshed problem will use more memory, the iterative solver uses much less memory that the direct solver, so you generally come out ahead.) 
Best Regards,