Running (Only) A Single-Point Energy Calculation In Crystal06/09, Proper Input Format For Long-Range Dispersion Contributions In Crystal09, And Removing The MPICH2 Content From The Output File In Pcrystal

Now enjoying the benefits of dispersion-corrected solid-state density functional theory (and a proper MPICH2 implementation for infrared intensity calculations, although this now a problem for reasons to be addressed in an upcoming post) in Crystal09, three issues in recent calculations caused me to think hard enough about keyword formats and job runs that I have opted to post briefly about what to do in case google and bing are your preferred methods of manual searching.

1. How To Run Only A Single-Point Energy Calculation In Crystal06/Crystal09

This had never come up before and, by the time I needed to find an input file to see what do to, the first google search provided Civalleri's Total Energy Calculation page that currently has broken links to .zip files. There is quite a bit about the different geometry optimization approaches in the manual, but a search for "single-point" provides no information about what to do for only single-point energy calculations.

The solution, it should be obvious after, is simply to not include the geometry optimization section in the input file. What would otherwise be the following (with arbitrary geometry optimization-like info between [COORDINATES] and [BASIS SETS]…




One problem solved by simply not having any optimization parameters (again, makes sense and is now google-able).

2. Proper GRIMME Input Format For Long-Range Dispersion Contributions In Crystal09

This is another example where one's first efforts in translating the manual into calculations may lead to considerable confusion until the proper format is finally identified (by which time you've run many pruned-down input tests).

1.05 20. 25.
1.05 20. 25. s6 (scaling factor) d (steepness) Rcut (cutoff radius)
1  0.14 1.001 Hydrogen Conventional Atomic number , C6 , Rvdw
6  1.75 1.452 Carbon Conventional Atomic number , C6 , Rvdw
7  1.23 1.397 Nitrogen Conventional Atomic number , C6 , Rvdw
8  0.70 1.342 Oxygen Conventional Atomic number , C6 , Rvdw
17 5.07 1.639 Chlorine Conventional Atomic number , C6 ,'Rvdw

I'm not even sure where the final ,'Rvdw comes from. Your .out file may terminate with the following error (or something similar)…

rank 7 in job 8  korterquad_51438   caused collective abort of all ranks
  exit status of rank 7: killed by signal 9

And the ERROR.peN file with any content will show the following, clearly pointing to a GRIMME-specific error…


The problem is the additional content within the manual pages for the GRIMME keyword that require pruning (or, at least, some identifier to show what is and what is not needed). The proper GRIMME section above is properly provided in the INPUT file as…

1.05 20. 25.
1  0.14 1.001
6  1.75 1.452
7  1.23 1.397
8  0.70 1.342
17 5.07 1.639

Where (see page 88 of the Crystal09 manual)…

GRIMME <- keyword is called
1.05 20. 25. <- scaling factor, steepness, cutoff distance
5 <- number of elements in the list (not the total number of atoms)
1  0.14 1.001 <- atomic number, dispersion coefficient, van der Waals radius

When all is properly run, the bottom of your output file will look something like the following:

 CYC  43 ETOT(AU) -5.784662098123E+03 DETOT  1.18E-11 tst  8.17E-15 PX  6.73E-08

 == SCF ENDED - CONVERGENCE ON ENERGY      E(AU) -5.7846620981229E+03 CYCLES  43


 TOTAL ENERGY(DFT)(AU)( 43) -5.7846620981229E+03 DE 1.2E-11 tester 8.2E-15



 SCALE FACTOR (S6):     1.0500

 GRIMME DISPERSION ENERGY (AU) -1.9723347118951E-01
 TOTAL ENERGY + DISP (AU) -5.7848593315941E+03


The Crystal09 manual refers you to Table 1 of the Stefan Grimme paper, "Semiempirical GGA-type density functional constructed with a long-range dispersion correction" (Journal of Computational Chemistry, Volume 27, Issue 15, Pages 1787 – 1799), which I've put together into the proper format below. Be sure to (1) delete the elements in parentheses ( -> get rid of the (H) <- ), (2) remove those atoms you do not need, (3) be sure to change the "number of elements" number for your structure, and (4) get and reference the Grimme paper so you have the proper C6 parameters and van der Waals radii accounted for (you'll be the right nitwit if I mis-copied something and you ran with it (although I trust my input), and you should have the reference regardless).

( H)   1   0.14 1.001
(Li)   3   1.61 0.825
(Na)  11   5.71 1.144
( K)  19  10.80 1.485
(Rb)  37  24.67 1.628
(Be)   4   1.61 1.408
(Mg)  12   5.71 1.364
(Ca)  20  10.80 1.474
(Sr)  38  24.67 1.606
( B)   5   3.13 1.485
(Al)  13  10.79 1.639
(Ga)  31  16.99 1.650
(In)  49  37.32 1.672
( C)   6   1.75 1.452
(Si)  14   9.23 1.716
(Ge)  32  17.10 1.727
(Sn)  50  38.71 1.804
( N)   7   1.23 1.397
( P)  15   7.84 1.705
(As)  33  16.37 1.760
(Sb)  51  38.44 1.881
( O)   8   0.70 1.342
( S)  16   5.57 1.683
(Se)  34  12.64 1.771
(Te)  52  31.74 1.892
( F)   9   0.75 1.287
(Cl)  17   5.07 1.639
(Br)  35  12.47 1.749
( I)  53  31.50 1.892
(He)   2   0.08 1.012
(Ne)  10   0.63 1.243
(Ar)  18   4.61 1.595
(Kr)  36  12.01 1.727
(Xe)  54  29.99 1.881
Y-Cd      24.67 1.639
Sc-Zn     10.80 1.562

Note that the d-block is identical for each row (so no atom numbers provided).

3. Removing The MPICH2 Content From The Output File In Pcrystal(/09)

This final issue does not occur in Pcrystal(/06) but does in Pcrystal(/09), with the reason being (I assume) the new use of MPICH2 in Pcrystal(/09) instead of MPICH in Pcrystal(/06).  The problem comes from running the following set of commands at the terminal window in MPICH2:

mpiexec -machinefile machine -np N /path/to/Pcrystal &>FILENAME.out &

Embedded within the FILENAME.out file will be all flavors of MPI-specific output, perhaps such as the following (in this case errors, but it happens in proper output as well):

application called MPI_Abort(MPI_COMM_WORLD, 1) - process 4
application called MPI_Abort(MPI_COMM_WORLD, 1) - process 7
rank 7 in job 9  korterquad_51438   caused collective abort of all ranks
 exit status of rank 7: return code 1 
rank 4 in job 9  korterquad_51438   caused collective abort of all ranks
 exit status of rank 4: killed by signal 9 


mpiexec_machine (handle_stdin_input 1089): stdin problem; if pgm is run in background...
mpiexec_machine (handle_stdin_input 1090):     e.g.: mpiexec -n 4 a.out < /dev/null &

The solution is to break up the mpiexec output from the Pcrystal output, performed by directing the mpiexec-specific content to, in this case, /dev/null (because it is not necessary except for diagnostic purposes).

mpiexec -machinefile machine -np N /path/to/Pcrystal < /dev/null &>FILENAME.out &

Which removes all traces of mpi-specific output from FILENAME.out.

Installing And Mounting Network Drives Using NFS In Ubuntu (And Generally)

This is another piece in an Ubuntu puzzle that, when assembled, will describe how to set up an MPI (message passing interface) computer cluster for running parallel calculations (upcoming).  As a brief explanation of what's going on, many of the MPI (OpenMPI, MPICH, MPICH2) set-up procedures you may stumble across online describe how to use the network file system (NFS) protocol to set up one directory on a host node (head node/server node/master node/whatever) of your cluster so that, by mounting a directory on a guest node (client node/slave node/whatever) to this network-accessible drive, the head and guest nodes all see the same work directory and executables (both MPI and your program of choice).  There are more clever ways to set the cluster up that will likely run at a slightly faster pace than NFS may allow, but we'll ignore that at the moment.  The install procedure below is Ubuntu-specific only in the apt-get stage (NFS support is not part of the default installation).  After all of the components are installed (post-apt-get), the setup should be Linux-universal.


Text in black – my ramblings.

Text in bold red – things you will type in the Terminal

Text in green – text you will either see or will type into files (using pico, my preference)

Below is all I need to do in Ubuntu to do what I need it to do.  I'll be dividing the installation procedure into HOST and GUEST sections for organizational purposes.

1. HOST Node Installation

a. sudo apt-get install nfs-kernel-server nfs-common portmap

My apt-get list is becoming gigantic as part of the cluster work, but I'm only focusing on NFS right now (if you intend on running any MPI-based code, you also need to include SSH), so we only need to deal with these three packages (they will also install libevent1, libgssglue1, libnfsidmap2, and librpcsecgss3, but that's the beauty of letting apt-get do the dirty work.  You can see this previous post if you intend on finding yourself installing any programs in Ubuntu while [shiver] not online).  You'll see plenty of output and, hopefully, no errors.

b. sudo dpkg-reconfigure portmap

Installing packages with NFS in the title makes sense.  What's the deal with portmap?  NFS uses remote procedure calls (RPCs) for communication.  Portmap is a server/service that maps these RPCs to their proper services (as a translator between RPC numbers and DARPA port numbers. Yup.), thereby directing cluster traffic.

The portmap configuration file (/etc/default/portmap) looks as below:

# Portmap configuration file
# Note: if you manually edit this configuration file,
# portmap configuration scripts will avoid modifying it
# (for example, by running 'dpkg-reconfigure portmap').

# If you want portmap to listen only to the loopback
# interface, uncomment the following line (it will be
# uncommented automatically if you configure this
# through debconf).

For the purposes of the cluster work to be done in upcoming posts, you do NOT want to uncomment the OPTIONS line (which would then bind loopback), not that you would start randomly uncommenting lines in the first place.

c. sudo /etc/init.d/portmap restart

If you make changes to the /etc/default/portmap configuration file, reconfigure portmap, etc., you'll need to restart portmap for the changes to be implemented.  It is recommended that you run this restart upon installation regardless (especially having run dpkg-reconfigure portmap above).

d. sudo mkdir /[work_directory]

This makes the directory to be shared among all of the other cluster machines.  Call it what you will.

e. sudo chmod a+wrx /[work_directory]

We now provide carte blanche to this directory so anyone can read, write, and execute programs in this directory.

f. sudo pico /etc/exports

The last file modification step on the HOST node will mount the /[work_directory] as an NFS-accessible directory to the GUEST machines and preserve this NFS accessibility until you change the settings (or the directory), preserving the accessibility upon reboot.

# /etc/exports: the access control list for filesystems which may be exported
#               to NFS clients.  See exports(5).
# Example for NFSv2 and NFSv3:
# /srv/homes       hostname1(rw,sync) hostname2(ro,sync)
# Example for NFSv4:
# /srv/nfs4        gss/krb5i(rw,sync,fsid=0,crossmnt)
# /srv/nfs4/homes  gss/krb5i(rw,sync)
/[work_directory] *(rw,sync)

To translate:  * = open up to all clients; rw = read-write priviledges to specified clients; sync = commit all changes to the disk before the server responds to some request making a change to the disk.  It is also worded as "read/write and all transfers to disk are committed to the disk before the write request by the client is completed" and "this option does not allow the server to reply to requests before the changes made by the request are written to the disk," which may or may not help to enlighten.  Basically, it makes sure the NEXT modification to some file doesn't occur until the CURRENT operation on that file is complete.

This only scratches the surface of all things /etc/exports but is enough for my purposes (anyone can mount the drive and read/write.  If your machine is online, let SSH take care of the rest of it).

g. sudo /etc/init.d/nfs-kernel-server restart

Having made the changes to /etc/exports, we restart the NFS server to commit those changes to the operating system.

h. sudo exportfs -a

If you RTFM, you know "the exportfs command is used to maintain the current table of exported file systems for NFS. This list is kept in a separate file named /var/lib/nfs/xtab which is read by mountd when a remote host requests access to mount a file tree, and parts of the list which are active are kept in the kernel's export table." (see HERE for more info).

With all of that completed, you will now have a network-accessible drive /[work_directory] sitting on the HEAD node.

Before moving on to the GUEST nodes, now what?  Again, based on other MPI and cross-network installation descriptions, a completely reasonable thing to do is build ALL of your cluster-specific programs (MPI and calculation programs) into /[work_directory].  You will then mount this directory on the client machines and set the PATHs on these machines to include /[work_directory]. Everyone then sees the same programs.

2. GUEST Node Installation

a. sudo apt-get install portmap nfs-common

This installs portmap and the NFS command files (but not the server) and also "starts up" the client NFS tools.  You should be ready to mount network drives immediately.

b. sudo mkdir /[work_directory]

We make the directory that will have the network drive mounted (the same name as the directory on the HOST node).  I've placed it in the same location in the directory hierarchy as it exists on the HEAD node (sitting right in /, not in /mnt or whatever).

For immediate access -> c1. sudo mount HOST_MACHINE:/[work_directory] /[work_directory]

Here, HOST_MACHINE may be an IP address (often something like 192.168.nn.nn or 10.1.nn.nn if you've set up your cluster on a switch, the actual IP address for the HOST machine if you know it (type ifconfig on the HOST machine to find out)) or a domain name (, for instance).  It's that simple (if everything installed properly).

For long-term, automated access -> c2a. sudo pico /etc/fstab

If you want to make this connection permanent (and this is a very good idea on a cluster), you can modify /etc/fstab by adding the following line:

HOST_MACHINE:/[work_directory] /[work_directory] nfs   rw   0   0

Then type

c2b. sudo mount /[work_directory]

As for additional information and discussion, there is quite a bit online already (as you might expect), with a long Ubuntu thread on the subject at  For a bit more technical information on the subject, check out