Firefly Frequently Asked Questions (somewhat outdated)

Q1. What are the files in the Firefly distribution?

A1. Precompiled binaries that run on different operating systems: Windows, Linux, and Mac OS X are provided as compressed ZIP files. Furthermore, different executables for different parallel environments are provided. Download one binary archive that best maches your system.

Q2. How do I run Firefly under Linux?

A2. Firefly runs natively under Linux. See the discussionon how to install and to use the Firefly under Linux.

Q3. What is the easiest way to run Firefly in parallel on Windows SMP/multicore system?

A3.Two changes that are required to get Firefly for Windows to run SMP parallel jobs on a single machine type setup:

Q4. Will Firefly work on (386, 486, various non-Intel but Intel-compatible) based systems?

A4. Firefly requires at least Pentium 4 (or compatible) class CPU. On the other hand, the quantum chemical calculations are very floating-point (FP) intensive, so you probably should use a faster processor. Current versions of Firefly are optimized for different modern processors.

Q5. Does Firefly run in parallel?

A5. Yes. Both SMP and clusters of computers are supported. The benefit of SMP is especially substantial for large MP3/MP4/MCQDPT2 calculations. Please read the documentation on how to execule Firefly in parallel

Q6. I've just found a bug in the Firefly. It does not work at all, or reports strange error messages (maybe simply hangs), or the results are definitely wrong. What should I do?

A6. Do as follows:
     First, check your input. If the problem disappears, that's fine.
     Second, check the documentation; then input once more!
     Third, you are encouraged to send us e-mail describing both your problem and the configuration of your computer and containing the sample input file.

Q7. What is the integral packing?

A7. Integral packing is the Firefly specific option that noticeably reduces the size of integral files. This option is turned on by default, and its using may lead to the results, which differ from the "exact" ones in the last digit(s). See the packing documentation for more details.

Q8. Is there any limitation for the maximum file size the Firefly can handle?

A8. It depends on your operating system and the file system. On Windows XP and Windows 2000 using the NTFS file system, Firefly can handle large files, although with minor limitations. Under Win95/98, the file size limit is 4 GByte if FAT32 volume is used as scratch storage, and 2 GByte otherwise. Maximum file size is 2 GByte for DOS, OS/2 HPFS, and some old Linux kernels and filesystems. Nevertheless, all Windows, OS/2, Linux, and Mac OS X Firefly versions are capable to handle large files by spliting them into smaller chunks.

Q9. Does Firefly support an assignment of the working files via the environment variables?

A9. This is currently supported only for input, punch, and ircdata files.

Q10. Are the Firefly sources available?

A10. Firefly sources are available under the terms of NDA with some additional limitations. For more information, contact Dr. Alex A. Granovsky.

Q11. When I run a job, the program is interrupted with the message
What is wrong with my input?

A11. The most common origin of this problem is as follows. In the Firefly's input, the first symbol of each line is treated in a special manner. If it contains any non-blank character, the rest of the current line is simply ignored (this looks like a Fortran-style comments). If the first symbol in the line is blank (space), then all other symbols of this line are read in and processed.

Q12. I tried to run Firefly under Windows. I used the command line suggested in the Firefly documentation. The program works, but I get only the screen output. On the disk, I find only the temporary files, but no output file.

A12. Do you run Firefly from the Windows command prompt window? The I/O redirection does not work properly if the program was started using Run  button in the Start Menu. You should always run Firefly in the command prompt window (or using a batch file).

Q13. Running Firefly, I've got the following error message:
          FSF: fatal error no. xxxxxxxx ...
What is this?

A13. These error messages are specific of the Firefly only. FSF is an abbreviation of the Fast System Files - a powerful set of fast non-Fortran file I/O subroutines. By default, the FSF subroutines are used by Firefly to perform almost all the file I/O operations. All the I/O errors are therefore reported as the specific FSF errors. Note that the most common FSF errors (0x00020070, 0xfffffffb, etc...) mean simply "out of disk space".

You can disable FSF support by setting the FASTF option to .False. in the $SYSTEM group. In this case, Firefly will use standard Fortran I/O calls. Thus, if the I/O error appears, you get a Fortran runtime error message. However, it is not recommended to disable this option.

Q14. I've got a message like:
What should I do?

A14. Check the virtual memory settings of your system. Try to increase the size of the paging file(s) or partitions. Do you have the requested amount of physical RAM installed? Other memory-related hints can also be helpful to you.

Q15. How does the SUSPEND/RESUME feature (Ctrl-C  and Ctrl-Break  signal handling) of Firefly work?

A15. The details of Ctrl-C  and Ctrl-Break  signal handling depend on the operating system used to run Firefly. Under Windows, pressing the Ctrl-Break  key also terminates Firefly instantly. On the other hand, pressing the Ctrl-C  key acts differently, namely, the following (self-explanatory) message appears:

Press X to terminate Firefly,
      T to set the new value of TIMLIM,
      or any other key to continue...
Note that:

Q16. Is it possible to run Firefly in such a way so it will not be automatically terminated during Windows NT log off process?

A16. Yes, it is possible. The simplest way to do this is to use at command to start Firefly job. To use at command, you should have installed and running the Schedule system service, and have the corresponding rights to access it.

That's all - your Firefly job is now in the Schedule queue and will be started at 11:00.
(See hints page for the information on how to organize your own job queue by using on-the-fly editing of batch and cmd files.)

If the Windows NT Resource Kit is installed on your system, there is also a couple of utilities that make things easier, namely winat and soon. While winat makes it easier to manage the scheduler queue, the very useful soon command allows one to schedule jobs in the near future. For example, the command

  soon cmd /c D:\test\task.cmd

will start your Firefly job after 5 seconds from now.

Certainly, it is still possible to manually terminate Firefly job started via at command. To do this, you can use pstat, (pmon, tlist, etc...) utility to get the PID of the process of interest, and then kill command to terminate it. Or, you can terminate process by its name (i.e., kill firefly). Alternatively, you can use the NT 4.0 task manager for this purpose.

Q17. Is there any telnet daemon available for Windows NT and OS/2?

A17. As to OS/2, the telnet daemon can be installed as a part of the IBM TCP/IP package. Use OS/2 detach command to start the desired job from inside your telnet session.
        As to NT, there is a lot of freeware, shareware, and commercial telnet daemons available in the market (we prefer the Telnet Server for Windows NT by Pragma Systems, Inc.). To start job from inside your remote session, simply follow the instructions in Q23.

Q18. Can Firefly calculate a Relaxed Potential Energy Surface (PES)?

A18. Yes. It is done with the RUNTYP=rsurface directive. See the example and the corresponding part of the documentation for more details.