One of these files is used to hot start the model. Hot start output is written to fort.67 and fort.68 on an alternating basis so that if the computer crashes in the process of writing one of these files, the other will be unaffected and can be used to hot start the model. Normally, the most current (in time) of the fort.67 or fort.68 files is used to hot start the model. On certain computers, the write buffer may not be emptied on a crash and other output files (e.g., time series output files fort.63, fort.64) may not be caught up to the time when the latest hot start file was written. In this case it would be necessary to restart the model using the earlier of the hot start files. Which (if either) hot start file is read in is determined by the parameter IHOT in the Model Parameter and Periodic Boundary Condition File.
It is often convenient to change parameter values in the Model Parameter and Periodic Boundary Condition File during the course of an ADCIRC run. (For example the duration of the run may be extended, nonlinear terms may be turned on or off, the value of the horizontal viscosity may be changed, etc.) A convenient way to accomplish this is via the hot start feature. The only parameters that can not be changed at the time of a hot start are the model time step, DTDP, and parameters having to do with time series or harmonic output. One exception to this limitation is the ending time of a time series output file which may be changed (e.g., if the length of the run is increased). However, changing the ending time of an output time series has one undesirable consequence since the number of output data sets contained in the file (i.e., how many different times output data will be written during the model run) is written at the beginning of the file. After a hot start, it is not possible to change this value in the time series output file and therefore it may not match the actual number of output data sets in the file. In this case it would be necessary to edit this number by hand in any affected time series output file before using the file in analysis or display software.
Writing hot start output files is controlled by the parameters NHSTAR and NHSINC in the Model Parameter and Periodic Boundary Condition File.
Hot start files are written in binary with record length of 8 bytes. Data contained in these files are shown via their variable names. Blanks are not included in the file and are shown below only to enhance readability. Loops indicate multiple data values. Conditional data are indicated by an if clause following the variable name. Definitions of each variable name are provided via hot links.
for k = 1 to NP
for j = 1 to NFEN
This line is included only if IDEN = 1
This line is included only if IDEN = 2
This line is included only if IDEN = 3
These lines are included only if IDEN = 4
end j loop
end k loop
The remainder of the lines in this file provide information required by the harmonic analysis routines and are included only if IHARIND = 1for k = 1 to MM
for j = 1 to MM
end j loop
end k loop
These lines included only if NOUTE = 1
These lines included only if NOUTV = 1
These lines included only if NOUTGE = 1
These lines included only if NOUTGV = 1
These lines included only if FMV > 0