Restarting Jaguar Jobs and Using Previous Results

Sometimes, you may find it useful to restart a job, either because you want to refine the results and do not want to start from the beginning of the calculation, because you want to alter the calculation slightly but want to use an initial guess or geometry from the previous run, or because you encountered some sort of problem that prevented the job from finishing. New input files, which are also called restart files, generated during each job can be used to restart the jobs. These files are automatically written to your local job directory at the end of a run; if the run did not finish, you can usually find the new input file by following the directions at the end of this section.

The restart file contains all the information needed for a new run, incorporating the results from the first run. This file contains the same job settings you made for the original input file for the job, but also contains the results of the job—the final wave function, the final geometry, and the like. Thus, if you want to restart the calculation with the wave function and other data already calculated, you can just read in the new input file. The file name is jobname.**.in, where the asterisks represent a two-digit number. This number is 01 if the name of the input file for the job from which it was generated is not in this form, and is otherwise set to the number after that assigned to the current input file. These files overwrite any other existing files of the same name.

As an example, if you run the job h2o, the restart file generated during the run is called h2o.01.in. You could then read this file, as described in Reading Jaguar Input Files into Maestro, and use it to continue on with the calculation, possibly after making some changes to the calculation requested. The new input file generated during this second run would be called h2o.02.in.

If you want to start a new job where the previous job left off, you need only read the new input file in, then make any changes you think are necessary—for example, you could change the SCF energy convergence criterion in the SCF tab. Similarly, if you want to perform an additional calculation once a geometry has been optimized, you can read in the restart file as input for the second job and make any necessary changes to it, such as selecting a DFT calculation instead of Hartree-Fock. Reading Jaguar Input Files into Maestro contains information on reading input files in the GUI. See The Jaguar Input File if you would like more information on input files.

Note that if you restart a run, you may not get exactly the same results as you would if you had simply performed a longer run in the first place, even if the calculation type is the same. The methods used in Jaguar sometimes use data from previous iterations, if this information is available, but the data may not be stored in the new input file. For example, the DIIS convergence scheme uses Fock matrices from all previous iterations for the run, and Fock matrices are not stored in new input files. However, calculations should ultimately converge to the same answer within a standard margin of error whether they are restarted or not.

If your run aborted or was killed before completion, and you want to restart the calculation or start another calculation where that one left off, you can look for a file called restart.in. The file is located in a subdirectory whose name is the same as the job’s, and which is found within the temp directory for the job, which was listed in the Job Settings Dialog Box.

By default, the restart.in file is written out at the end of the Jaguar programs for calculating the initial guess, performing the SCF iterations, and calculating a new geometry for geometry optimizations, as well as at the end of each SCF iteration. (To turn off restart.in file generation, the input file output keywords ip151 and/or ip152 in the gen section should be set to 0.) The restart.in file is overwritten each time, so that the final version is written either at the end of the run or just prior to any problems encountered.