58 



The examples in this dissertation were all computed on a Intel 90MHz Pentium 

 processor based PC with 32MB of RAM, running the Linux operating system. As an 

 order of magnitude estimate, the shortest computation time for an example in this 

 chapter is 4.8 minutes and 7.8 x 10^ flops for the complete laboratory record presented 

 in figure 3.19. The longest computation time required was 71 minutes and 582 x 10^ 

 flops for the shallow water wave presented in figure 3.4. There are a number of 

 reasons for this large variation in computation time. The first is simply the number 

 of window solutions computed. As each window solution is computed separately, 

 the computation time increases linearly with the number of windows computed. If 

 computational time is a concern, this can be taken into account when choosing the 

 output spacing. The other reason that the shallow water wave takes much longer 

 to compute is that there are a number of windows that did not converge with the 

 first set of computational parameters. The optimization is run for many iterations 

 to ensure that it won't converge. As the parameters are varied, the computation is 

 repeated. This process takes a great deal of time. 



With further development, it may be possible to determine a set of criteria for the 

 computational parameters by examining the segment of the record in a given window. 

 This would be far more efficient than simply attempting a solution with a variety of 

 values until convergence is achieved. 



