Benchmarks

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=Benchmarks performed with NWChem=

This page contains a suite of benchmarks performed with NWChem. The benchmarks include a variety of computational chemistry methods on a variety of high performance computing platforms. The list of benchmarks available will evolve continuously as new data becomes available. If you have benchmark information you would like to add for your computing system, please contact one of the developers.
 
=Hybrid density functional calculation on the C<sub>240</sub> Buckyball=

Performance of the Gaussian basis set DFT module in NWChem. This calculation involved performing a PBE0 calculation (in direct mode) on the on C<sub>240</sub> system with the 6-31G* basis set (3600 basis functions) without symmetry. These calculations were performed on the Chinook supercomputer located at PNNL. Timings are per step for the various components. The [[Media:input_c240_pbe0.nw|input file]] is available.

[[File:dft-scaling-c240-pbe02.png|center|300px]]

=Parallel performance of ''Ab initio'' Molecular Dynamics using plane waves= 
[[file:PWScaling.png|left|320px |thumb|AIMD Parallel timings for <math>UO_2^{2+}</math>+122<math>H_2</math>O. These calculations were performed on the Franklin Cray-XT4 computer system at NERSC.]]
[[file:PWMDScaling.png|center|320px| thumb|AIMD and AIMD/MM Parallel Timings for <math>Zn^{2+}</math>+64<math>H_2</math>O (unit cell parameters SC=12.4 Angs. and  cutoff energy =100Ry).  These calculations were performed on the Chinook HP computer system at MSCF EMSL, PNNL.]]
[[file:PWEXScaling.png|left|320px|thumb|Exact exchange timings – 80 atom cell of hematite (cutoff energy=100Ry). These calculations were performed on the Franklin Cray-XT4 computer system at NERSC.]]
[[file:water192b.png|center|320px|thumb|Exact exchange timings – 576 atom cell of water (cutoff energy=100Ry). These calculations were performed on the Hopper Cray-XE6 computer system at NERSC.]]

=Parallel performance of the CR-EOMCCSD(T) method (triples part)= 

An example of the scalability of the triples part of the [http://dx.doi.org/10.1063/1.3385315 CR-EOMCCSD(T) approach] for Green Fluorescent Protein Chromophore (GFPC)
described  by cc-pVTZ basis set (648 basis functions) as obtained from NWChem. Timings were determined from calculations on the Franklin Cray-XT4 computer system at NERSC.
See the [[Media:input_gfpc.nw| input file]] for details.

[[File:creomccsd_t.png|center|500px| ]]


And more recent scalability test of the CR-EOMCCSD(T) formalism (Jaguar Cray XT5 at ORNL, see K. Kowalski, S. Krishnamoorthy, R.M. Olson, V. Tipparaju, E. Apra, 
SC2011, for details).

[[File:curve_bg_lumo.png|center|500px]]

=Parallel performance of the multireference coupled cluster (MRCC) methods =

In collaboration with Dr. Jiri Pittner's group from   Heyrovsky Institute of Physical Chemistry implementations of two variants of state-specific MRCC approaches
have been developed. During his internship at PNNL Jirka Brabec, using novel processor-group-based algorithms,  implemented Brillouin-Wigner and Mukherjee MRCC models with  singles and doubles. The scalabililty  tests for the Brillouin-Wigner MRCCSD approach have been performed on Jaguar XT5 system at ORNL for <math>\beta </math>-carotene in 6-31 basis set (472 orbitals, 216 correlated electrons, 20 reference functions; see J.Brabec, J. Pittner, H.J.J. van Dam, E. Apra, K. Kowalski, JCTC 
2012, 8(2), pp 487–497). Currently, PNNL postdoctoral fellow Dr. Kiran Bhaskaran Nair is developing  perturbative MRCCSD(T) approaches, which accounts for the effect of triple excitations. 

[[File:mrccsd_scalability.png|center|500px]]


Scaling of the triples part of the BW-MRCCSD(T) method for <math>\beta </math>-carotene in 6-31 basis set (JCP 137, 094112 (2012)).  The scalability tests of the
BW-MRCCSD(T) implementation of NWChem have been performed on the Jaguar Cray-XK6 computer system of the National Center for Computational Sciences at Oak Ridge National Laboratory.

[[File:Mrccsd_t_titan.png|center|500px]]

=Timings of CCSD/EOMCCSD for the oligoporphyrin dimer =

CCSD/EOMCCSD timings for oligoporphyrin dimer (942 basis functions, 270 correlated electrons, D2h symmetry, excited-state calculations were 
performed for state of b1g symmetry, in all test calculation convergence threshold was relaxed, 1024 cores were used). See the [[Media:input_p2ta.nw| input file]] for details.

 --------------------------------------------------------
  Iter          Residuum       Correlation     Cpu    Wall
  --------------------------------------------------------
    1   0.7187071521175  -7.9406033677717   640.9   807.7
    ......
  MICROCYCLE DIIS UPDATE: 10 5
   11   0.0009737920958  -7.9953441809574   691.1   822.2
  --------------------------------------------------------
  Iterations converged
  CCSD correlation energy / hartree =        -7.995344180957357
  CCSD total energy / hartree       =     -2418.570838364838890
 
  EOM-CCSD right-hand side iterations
  --------------------------------------------------------------
       Residuum       Omega / hartree  Omega / eV    Cpu    Wall
  --------------------------------------------------------------
 ......
 Iteration   2 using    6 trial vectors
   0.1584284659595   0.0882389635508    2.40111   865.3  1041.2
 Iteration   3 using    7 trial vectors
   0.0575982107592   0.0810948687618    2.20670   918.0  1042.2


=Performance tests of the GPU implementation of non-iterative part of  the CCSD(T) approach=

Recent tests of the GPU CCSD(T) implementation performed on Titan Cray XK7 system at ORNL
(C22H14, 378 basis set functions, C1 symmetry; 98 nodes: 8 cores per node + 1GPU)

 Using CUDA CCSD(T) code 
 Using 0 device(s) per node 
 CCSD[T] correction energy / hartree = -0.150973754992986 
 CCSD[T] correlation energy / hartree = -3.067917061062492 
 CCSD[T] total energy / hartree = -844.403376796441080 
 CCSD(T) correction energy / hartree = -0.147996460406684 
 CCSD(T) correlation energy / hartree = -3.064939766476190 
 CCSD(T) total energy / hartree = -844.400399501854849 
 Cpu & wall time / sec 9229.9 9240.3 


 Using CUDA CCSD(T) code 
 Using 1 device(s) per node  
 CCSD[T] correction energy / hartree = -0.150973754993019 
 CCSD[T] correlation energy / hartree = -3.067917061062597 
 CCSD[T] total energy / hartree = -844.403376796441307 
 CCSD(T) correction energy / hartree = -0.147996460406693 
 CCSD(T) correlation energy / hartree = -3.064939766476270 
 CCSD(T) total energy / hartree = -844.400399501854963 
 Cpu & wall time / sec 1468.0 1630.7 


Without GPU  9240.3 sec.
With      GPU  1630.7 sec.

Next release: GPU implementation of non-iterative part of the MRCCSD(T) approach
(K. Bhaskarsan-Nair, W. Ma, S. Krishnamoorthy, O. Villa, H. van Dam,
E. Apra, K. Kowalski, J. Chem. Theory Comput. 9, 1949 (2013))

[[File:GPU_MRCCSD_T.png|center|500px]]

=Current developments for high accuracy: alternative task schedulers (ATS)=

Currently various development efforts are underway for high accuracy methods that will be available in future releases of NWChem. The examples below shows the first results of the performance of the triples part of Reg-CCSD(T) on GPGPUs (left two examples) and of using alternative task schedules for the iterative CCSD and EOMCCSD.

<gallery widths=170px perrow=5>
File:gpu_scaling_spiro.png|<small>''Scalability of the triples part of the Reg-CCSD(T) approach for Spiro cation described by the Sadlej's TZ basis set (POL1).
The calculations were performed using Barracuda cluster at EMSL.</small>
File:gpu_speedup_uracil.png|<small>''Speedup of GPU over CPU of the (T) part of the (T) part of the Reg-CCSD(T) approach as a function of the tile size for the uracil molecule. 
The calculations were performed using Barracuda cluster at EMSL.</small>
File:ccsd_eomccsd_new.png|<small>''Comparison of the CCSD/EOMCCSD iteration times  for BacterioChlorophyll  (BChl, Mg O6 N4 C 36 H38)  for various tile sizes. Calculations were performed for 3-21G basis set (503 basis  functions, C1 symmetry, 240 correlated electrons, 1020 cores).</small>
File:bchl_6_311G_ccsd.png|<small>''Time per CCSD iteration for BChl in 6-311G basis set (733 basis functions, C1 symmetry, 240 correlated electrons, 1020 cores) as a function of tile size.</small>
File:eomccsd_scaling_ic.png|<small>''Scalability of the CCSD/EOMCCSD codes for BChl in 6-311G basis set (733 basis functions; tilesize=40, C1 symmetry, 240 correlated electrons).</small>
</gallery>



Other tests:

The impact of the tilesize on the CCSD(ATS) timings: All tests have been performed for uracil trimer (6-31G* basis set; all core electrons frozen) 
on Hopper using 25 nodes (600 cores). One can observe almost 10-fold speedup of the CCSD(ATS) code for tilesize=40 compared to standard TCE CCSD implementation 
using tilesize=12.

[[File:uracil_trimer.png|center|550px]]


Performance tests for water clusters

[[File:CTF.png|center|550px]]




Luciferin (aug-cc-pVDZ basis set; RHF reference; frozen core)  - time per CCSD iteration  ([[Media:luciferin.nw| input file]])
  
  tilesize = 30 
    256 cores      644 sec.
    512            378 sec.
    664            314 sec.
   1020            278 sec.
   1300            237 sec.

  tilesize = 40
     128             998 sec.
     256             575 sec.


Sucrose (6-311G** basis set; RHF reference; frozen core) - time per CCSD iteration ([[Media:sucrose.nw| input file]])

 tilesize = 40
    256 cores   1486 sec. 
    512          910 sec.
   1024          608 sec.


Cytosine-OH (POL1; UHF reference; frozen core) - time per EOMCCSD iteration ([[Media:cytosine_oh_pol1.nw| input file]])

  tilesize = 30
  256 cores    44.5 sec.

  tilesize = 40 
  128 cores    55.6 sec.