Error messages 



319. An error message gives information about a "fatal" error, that is, 

 an error detected that would stop the calculation. On the data entry level, 

 these errors might be caused by inconsistencies in specified quantities (for 

 example, specifying three groins but only giving positions for two) or a 

 serious problem in the calculation (for example, running many high waves at 

 extremely oblique incident wave angles). GENESIS is based on physical 

 assumptions and calculation techniques that have limitations (as described in 

 Part V). If these limitations are exceeded, the simulation may fail or give 

 an erroneous result. Experience with GENESIS in a variety of projects 

 indicates it will perform satisfactorily if prudence is taken to represent 

 realistic wave, structure, and shoreline position conditions. 



Warnings 



320. Warnings are given if a potentially undesirable condition is 

 detected in the course of calculation. One of the more common warnings is 

 that the stability parameter STAB (called "R s " in the main text) has 

 exceeded the value of 5.0 during a particular time step (see Part V). If 

 STAB > 5.0 for too many time steps (as judged by the user) or if a number of 

 STAB values are very large, the calculation is likely to be numerically inac- 

 curate. In this case, the time interval DT should be decreased. The 

 exception to this discussion of STAB is use of GENESIS in scoping or preli- 

 minary analysis, for which results need only be qualitative and where large 

 time steps may be desirable to reduce computation time. 



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