the openkim testing framework for interatomic potentials...

27
Ellad B. Tadmor and Ryan S. Elliott Department of Aerospace Engineering and Mechanics University of Minnesota LAMMPS Users’ Workshop, Albuquerque, NM, August 1-3, 2017 The OpenKIM testing framework for interatomic potentials NSF CDI and CDS&E programs Collaborators: James Sethna, Daniel Karls, Matthew Bierbaum, John Hooper.

Upload: others

Post on 18-Jun-2020

14 views

Category:

Documents


0 download

TRANSCRIPT

Page 1: The OpenKIM testing framework for interatomic potentials ...lammps.sandia.gov/workshops/Aug17/pdf/tadmor.pdf · The OpenKIM testing framework for interatomic potentials NSF CDI and

Ellad B. Tadmor and Ryan S. ElliottDepartment of Aerospace Engineering and MechanicsUniversity of Minnesota

LAMMPS Users’ Workshop, Albuquerque, NM, August 1-3, 2017

The OpenKIM testing framework for interatomic potentials

NSF CDI and CDS&E programs

Collaborators: James Sethna, Daniel Karls, Matthew Bierbaum, John Hooper.

Page 2: The OpenKIM testing framework for interatomic potentials ...lammps.sandia.gov/workshops/Aug17/pdf/tadmor.pdf · The OpenKIM testing framework for interatomic potentials NSF CDI and

Ellad B. Tadmor (University of Minnesota)

OpenKIM

2

Open Knowledgebase of Interatomic Models (OpenKIM)

• Development of an online open resource for standardized testing long-term warehousing of interatomic models (potentials and force fields) and data.

• Development of an application programming interface (API) standard for atomistic simulations, which will allow any interatomic model to work seamlessly with any atomistic simulation code.

• Development of a quantitative theory of transferability of interatomic models to provide guidance for selecting application-appropriate models based on rigorous criteria, and error bounds on results.

Project Objectives

PIs: Ellad Tadmor (U. Minn), Ryan Elliott (U. Minn), James Sethna (Cornell)

Funding: NSF CDI (2009-2014); NSF CDS&E (2014-)

Page 3: The OpenKIM testing framework for interatomic potentials ...lammps.sandia.gov/workshops/Aug17/pdf/tadmor.pdf · The OpenKIM testing framework for interatomic potentials NSF CDI and

Ellad B. Tadmor (University of Minnesota)

KIM Overview

3

Repository: A user-extendible database of ‣ interatomic Models‣ standardized Tests (simulation codes)‣ Predictions (results from Model-Test couplings)‣ Reference Data (obtained from experiments

and first principles calculations)

Web portal: A web interface that facilitates: ‣ user upload and download of Tests, Models, and

Reference Data‣ searching and querying the repository‣ comparing and visualizing Predictions and Reference Data‣ recording user feedback

Processing pipeline: An automatic system for generating Predictions by mating Tests and Models in the KIM Repository.‣ puts the “knowledge” in “knowledgebase”‣ employs virtual machines and cloud-based computing

Page 4: The OpenKIM testing framework for interatomic potentials ...lammps.sandia.gov/workshops/Aug17/pdf/tadmor.pdf · The OpenKIM testing framework for interatomic potentials NSF CDI and

Ellad B. Tadmor (University of Minnesota)

KIM Philosophy on an Interatomic Model

4

‣ An interatomic model (IM) can be understood to mean different things.

I. The functional form of LJ:

Consider the following views of the Lennard-Jones (LJ) potential:

II. The LJ parameter set for a given material:

Argon

✏ = 0.0104 eV

� = 3.40 ˚

A

This is common in EAM potentials where the parameter file is considered to be the potential.

⇤(r) = 4�

⇤�⇥

r

⇥12�

�⇥

r

⇥6⌅

III. A computer implementation of the LJ potential:

subroutine ljpotential(r,sig,eps,func,dfunc,d2func)implicit none

!-- Transferred variablesdouble precision, intent(in) :: r, sig, epsdouble precision, intent(out) :: func, dfunc, d2func

!-- Local variablesdouble precision rm,rm2,rm6,eos24

rm = sig/r ! sig/r rm2 = rm*rm ! (sig/r)^2rm6 = rm2*rm2*rm2 ! (sig/r)^6eos24 = 24.0*eps/sig

func = 4.0*eps*rm6*(rm6-1.0)dfunc = eos24*rm*rm6*(-2.0*rm6+1.0)d2func = (eos24/sig)*rm2*rm6*(26.0*rm6-7.0)

end subroutine ljpotential

Page 5: The OpenKIM testing framework for interatomic potentials ...lammps.sandia.gov/workshops/Aug17/pdf/tadmor.pdf · The OpenKIM testing framework for interatomic potentials NSF CDI and

Ellad B. Tadmor (University of Minnesota)

Why a is a Parameter Set not enough ?

5

‣ Interatomic models are often stored as a table of discrete data points that are interpolated by the simulation code:

r1 ɸ(r1)

r2 ɸ(r2)

r3 ɸ(r3)

... ...

‣ The interpolation choice (e.g. spline order) affects some results,

e.g. Quasi-harmonic estimate of the elastic constant for a 1D chain of atoms interacting via a nearest-neighbor Morse pair potential:

c = a

�00(a) +

kBT

2

�(4)(a)�00(a)� (�00(a))2

(�00(a))2

Interpolation E↵ects in Tabulated Potentials 14

0

5

c[nN]

0 500 1000T [K]

n=500

QH: 3N,3HQH: 4CQH: A,5C,5HMD: 3PMD: 5PQH: 3PQH: 5P

(a)

0

5

c[nN]

0 500 1000T [K]

n=2000

QH: A,5C,5H

QH: 3N,3H

QH: 4C

(b)

0

5

c[nN]

0 500 1000T [K]

n=10000

QH: A,5C

QH: 3N,3H

QH: 5H

QH: 4C

MD: AMD: 3N,3C,4C,5C,5H

(c)

Figure 4: Stress-free spatial elastic constant (tangent modulus) as a function of

temperature computed using the QH approximation with a tabulated modified Morse

potential using di↵erent splines with (a) n = 500 knots; (b) n = 2, 000 knots; (c)

n = 10, 000 knots. In addition to the lattice dynamics QH approximation results, frame

(a) also shows the QH and MD results computed using pure cubic and quintic polynomial

potentials, and frame (c) also shows the MD results computed using the analytic and

spline potentials.

pair potential is [4],

c = a

00(a) +k

B

T

2

(4)(a)�00(a)� (�000(a))2

(�00(a))2

�, (12)

where a = a(T ) is the stress-free equilibrium lattice constant at temperature T . The

value of c as a function of temperature for the spline and analytic potentials is presented

in figure 4. We see that the results obtained for the clamped quintic spline potential

agree well with the analytic potential results, even when the number of knots is on

the order of n = 500. The results obtained using the quintic Hermite spline potential

agree with the analytic results when the number of data points is not too large (e.g.,

n = 500 and n = 2, 000). However, due to the increased sensitivity to numerical

noise from the use of numerical di↵erentiation, the results of the quintic Hermite spline

degrade somewhat when n = 10, 000 data points are used. This is in agreement with

figures 1d and 1f where the quintic Hermite spline predicts worse fourth-order derivative

values with more data points. Thus, at least for the quintic Hermite spline, increasing

the number of knots does not necessarily lead to better accuracy. The results for the

clamped quartic spline are interesting. Although this spline is only C

3 continuous it is

able to follow the analytic curve on average, and shows better results with more data

points.

Unlike the higher-order quartic and quintic splines, the cubic splines (natural and

Hermite) produce a quantitatively di↵erent behavior for the temperature-dependent

elastic constant. In fact, they predict entirely the wrong initial slope at T = 0.

Increasing the number of knots decreases the discontinuity in the cubic spline results

Wen et al., MSMSE,23:074008 (2015)

Page 6: The OpenKIM testing framework for interatomic potentials ...lammps.sandia.gov/workshops/Aug17/pdf/tadmor.pdf · The OpenKIM testing framework for interatomic potentials NSF CDI and

Ellad B. Tadmor (University of Minnesota)

KIM Models

6

‣ The KIM framework defines an interatomic model as follows.

• A KIM Model is an autonomous computational entity:

KIM Modelatomic

configurationenergy and

its derivatives

1.Stand-alone Model for a particular functional form and parameters.

• KIM Models can have two forms:

2.Parameterized Model that is read in by a Model Driver; for example:

⇤(r) = 4�

⇤�⇥

r

⇥12�

�⇥

r

⇥6⌅

Lennard-Jones Model Driver: Material specific LJ Models:

Argon; ϵAr=10.4 meV, σAr=0.340 nmKrypton; ϵKr=14.0 meV, σKr=0.365 nm...

(Computer implementation including any interpolations or other data processing.)

(Each Model is a parameter file read in by its Model Driver.)

Page 7: The OpenKIM testing framework for interatomic potentials ...lammps.sandia.gov/workshops/Aug17/pdf/tadmor.pdf · The OpenKIM testing framework for interatomic potentials NSF CDI and

Ellad B. Tadmor (University of Minnesota)

Portability and the KIM API Standard

7

‣ In order to maximize the portability of KIM Models, anApplication Programming Interface (API) standards has been defined for exchanging information between simulators and models.

Simulator(simulation code)

Model(interatomic potential)

main program subroutine

pointer

pointer

standardized,packed data

structure“API Object”

• Stand-alone simulation computer program (MD, lattice dynamics, etc.)

• Can be written in any language supported by the API (Fortran 77, Fortran 90, Fortran 2003, C, C++, ...)

• Subroutine that given a set of atomic positions, species, ... computes energy, forces, ...

• Can be written in any language (Fortran 77, Fortran 90, Fortran 2003, C, C++, ...)

‣ Currently working on support for electrostatics and charge equilibration.

Page 8: The OpenKIM testing framework for interatomic potentials ...lammps.sandia.gov/workshops/Aug17/pdf/tadmor.pdf · The OpenKIM testing framework for interatomic potentials NSF CDI and

Ellad B. Tadmor (University of Minnesota)

Efficiency of the KIM API

8

‣ The KIM API is a lightweight efficient interface.

1 8 64 5120

20

40

60

80

100

Number of Processors

Para

llel E

fficie

ncy

(%)

Scaled−sized EAM Cu

LAMMPS Model Newton On (6.8439)LAMMPS Model Newton Off (7.69809)KIM Model (10.3464)

1 8 64 5120

20

40

60

80

100

Number of Processors

Para

llel E

fficie

ncy

(%)

Scaled−sized Lennard−Jones Argon

LAMMPS Model Newton On (10.4684)LAMMPS Model Newton Off (12.214)KIM Model (12.6469)

Lennard-Jones Argon EAM Copper

LAMMPS benchmark results (scaled size with 32,000 atoms per core)

Page 9: The OpenKIM testing framework for interatomic potentials ...lammps.sandia.gov/workshops/Aug17/pdf/tadmor.pdf · The OpenKIM testing framework for interatomic potentials NSF CDI and

Ellad B. Tadmor (University of Minnesota)

KIM-Compliant Codes

9

Page 10: The OpenKIM testing framework for interatomic potentials ...lammps.sandia.gov/workshops/Aug17/pdf/tadmor.pdf · The OpenKIM testing framework for interatomic potentials NSF CDI and

Ellad B. Tadmor (University of Minnesota)

Example: Using KIM Models with LAMMPS

10

‣ Using KIM Models with LAMMPS is straightforward:

• Install the KIM API from source or using binary packages (packages available for Ubuntu, CentOS, Fedora, OpenSUSE, others in development).

• Precede LAMMPS installation with “make yes-kim”

For more info, see http://lammps.sandia.gov/doc/pair_kim.html

• Replace native potential with pair style KIM and KIM ID

pair_style kim LAMMPSvirial EAM_Dynamo_Ercolessi_Adams_Al__MO_123629422045_001pair_coeff * * Almass 1 26.98

pair_style eam/alloypair_coeff * * Al_ercolessiAdams.alloy Al

• Run as usual

• Add the KIM Models that you want to use. (Binary packages have option to add all models.)

Page 11: The OpenKIM testing framework for interatomic potentials ...lammps.sandia.gov/workshops/Aug17/pdf/tadmor.pdf · The OpenKIM testing framework for interatomic potentials NSF CDI and

Ellad B. Tadmor (University of Minnesota)

MDStressLab (http://mdstresslab.org)

11

‣ MDStressLab is a program for computing stress fields from MD simulation results

INPUTParticle coordinates, velocities, and species

Available athttp://mdstresslab.org

COMPUTE:

• Calculated Cauchy and first PK versions of Hardy, Tsai and virial stress

• Decompose stress field into unique and non-unique parts

grid information

Model KIM ID

weighting function

Reference:N. C. Admal and E. B. Tadmor,J. Elast., 100:63, 2010

Page 12: The OpenKIM testing framework for interatomic potentials ...lammps.sandia.gov/workshops/Aug17/pdf/tadmor.pdf · The OpenKIM testing framework for interatomic potentials NSF CDI and

Ellad B. Tadmor (University of Minnesota)

Model Verification Checks

12

‣ All KIM Models are subjected to Verification Checks when uploaded to openkim.org.

Mandatory

• Species supported as stated;

• Unit conversion handled correctly;

• Domain decomposition handled correctly;

• ...

Consistency

• Numerical derivative check of forces, virial, hessian, ...

• Translational and rotational invariance;

• ...

Informational

• Smooth energy, forces, etc. at cutoff;

• Inversion symmetry;

• Coding issues: Dependence on optimiztion, memory leaks, etc.

• ...

Page 13: The OpenKIM testing framework for interatomic potentials ...lammps.sandia.gov/workshops/Aug17/pdf/tadmor.pdf · The OpenKIM testing framework for interatomic potentials NSF CDI and

Ellad B. Tadmor (University of Minnesota)

A Simulation is only as good as the Potential

13

‣ The predictive capability of an atomistic simulation is dependent on the fidelity of the interatomic model.

Example: Projectile impacting silicon plate

Tersoff Stillinger-Weber

Page 14: The OpenKIM testing framework for interatomic potentials ...lammps.sandia.gov/workshops/Aug17/pdf/tadmor.pdf · The OpenKIM testing framework for interatomic potentials NSF CDI and

Ellad B. Tadmor (University of Minnesota)

KIM Tests

14

Test: A computer program that when coupled with a suitable Model generates one or more Predictions, each of which is associated with a specific KIM Property.

• Test Types

- Test (stand-alone test limited to a single case, or a parameter set to a driver)

- Test Driver + Parameter Set (can work with multiple conditions)

- A “canonical property”, i.e. a basic atomistic property to which Models are often fitted and from which larger-scale behavior might be inferred.

Bulk- lattice constants- cohesive energy- elastic constants- phonon spectrum- ..Wall

- surface energy- surface structure- gamma surface- grain boundary structure- ...Line- dislocation core structure

- dislocation core energy- Peierls barrier- ...Point- vacancy formation energy- vacancy migration barrier- ...

- An “ideal” physical property without reference to the algorithmic details of how it is computed (e.g. “melting temperature” as opposed to a specific approach for getting it).

• What constitutes a KIM Property?

A Test can be a program or an input file to an installed Simulator (e.g. LAMMPS)

Page 15: The OpenKIM testing framework for interatomic potentials ...lammps.sandia.gov/workshops/Aug17/pdf/tadmor.pdf · The OpenKIM testing framework for interatomic potentials NSF CDI and

Ellad B. Tadmor (University of Minnesota)

Couple Test T with all valid Models and store resulting Predictions in Repository.

Model 1Model 2Model 3Model 4

Interacting with KIM

15

Web portal

Repository Processing pipeline

KIMTest T

Uploading new KIM Test to the OpenKIM Repository

... Model Predictions ...

Page 16: The OpenKIM testing framework for interatomic potentials ...lammps.sandia.gov/workshops/Aug17/pdf/tadmor.pdf · The OpenKIM testing framework for interatomic potentials NSF CDI and

Ellad B. Tadmor (University of Minnesota)

KIM Visualization

16

‣ KIM Visualizers are designed to display/analyze Test results (i.e. Property Instances) and are displayed on Model pages.

Cohesive energy curve FCC Lattice Constant

• plotting the results using Javascript libraries and templates developed in KIM

KIM Visualizers work by

• querying openkim.org to obtain desired Test results (see https://query.openkim.org/)

Follow the tutorials to adapt a visualizer to your own needs

Page 17: The OpenKIM testing framework for interatomic potentials ...lammps.sandia.gov/workshops/Aug17/pdf/tadmor.pdf · The OpenKIM testing framework for interatomic potentials NSF CDI and

Ellad B. Tadmor (University of Minnesota)

KIM Models (https://openkim.org)

17

‣ KIM Models are archived on the OpenKIM website https://openkim.org :

Page 18: The OpenKIM testing framework for interatomic potentials ...lammps.sandia.gov/workshops/Aug17/pdf/tadmor.pdf · The OpenKIM testing framework for interatomic potentials NSF CDI and

Ellad B. Tadmor (University of Minnesota)

KIM Models (https://openkim.org)

18

Page 19: The OpenKIM testing framework for interatomic potentials ...lammps.sandia.gov/workshops/Aug17/pdf/tadmor.pdf · The OpenKIM testing framework for interatomic potentials NSF CDI and

Ellad B. Tadmor (University of Minnesota)

KIM Models (https://openkim.org)

19

Page 20: The OpenKIM testing framework for interatomic potentials ...lammps.sandia.gov/workshops/Aug17/pdf/tadmor.pdf · The OpenKIM testing framework for interatomic potentials NSF CDI and

Ellad B. Tadmor (University of Minnesota)

KIM Models (https://openkim.org)

20

Unique archival KIM ID for citation in papers

Scientific reference for the potential.

Page 21: The OpenKIM testing framework for interatomic potentials ...lammps.sandia.gov/workshops/Aug17/pdf/tadmor.pdf · The OpenKIM testing framework for interatomic potentials NSF CDI and

Ellad B. Tadmor (University of Minnesota)

KIM Models (https://openkim.org)

21

Usertime muliplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run.

Full results page.

Expand a property synopsis.

Further down the model page for EAM_Dynamo_Mishin_Mehl_Cu__MO_346334655118_002

Page 22: The OpenKIM testing framework for interatomic potentials ...lammps.sandia.gov/workshops/Aug17/pdf/tadmor.pdf · The OpenKIM testing framework for interatomic potentials NSF CDI and

Ellad B. Tadmor (University of Minnesota)

KIM Models (https://openkim.org)

22

Elastic constants (note that c44 is negative indicating the sc structure is unstable).

Further down the model page for EAM_Dynamo_Mishin_Mehl_Cu__MO_346334655118_002

Page 23: The OpenKIM testing framework for interatomic potentials ...lammps.sandia.gov/workshops/Aug17/pdf/tadmor.pdf · The OpenKIM testing framework for interatomic potentials NSF CDI and

Ellad B. Tadmor (University of Minnesota)

KIM Models (https://openkim.org)

23

Page 24: The OpenKIM testing framework for interatomic potentials ...lammps.sandia.gov/workshops/Aug17/pdf/tadmor.pdf · The OpenKIM testing framework for interatomic potentials NSF CDI and

Ellad B. Tadmor (University of Minnesota)

KIM Models (https://openkim.org)

24

Page 25: The OpenKIM testing framework for interatomic potentials ...lammps.sandia.gov/workshops/Aug17/pdf/tadmor.pdf · The OpenKIM testing framework for interatomic potentials NSF CDI and

Ellad B. Tadmor (University of Minnesota)

Current Status (August 1, 2017)

25

Web portal

Repository Processing pipeline

• 189 Models

• 2612 Tests

• 53 property definitions

• 9 visualizers

• Interface to explore content

• Content upload by members

• Forums and Wikis for member input

• Online bootcamp w/lectures

• Automatic VM-based computations

• Downloadable KIM VM

• Handling of dependencies

Software supporting KIM API:

ASAP, ASE, DL_POLY, GULP, IMD, LAMMPS, libAtoms/QUIP, nanoHUB, Potfit, Quasicontinuum, VirtualFab, MDStressLab

Page 26: The OpenKIM testing framework for interatomic potentials ...lammps.sandia.gov/workshops/Aug17/pdf/tadmor.pdf · The OpenKIM testing framework for interatomic potentials NSF CDI and

Ellad B. Tadmor (University of Minnesota)

Summary

26

KIM provides archival permanent storage of interatomic models, tests, and reference data with known provenance.

All KIM content is citable with unique permanent identifiers. This makes it possible to reproduce simulation results in the future.

Models stored in the OpenKIM Repository are portable as they conform to an API that allows them to run seamlessly with any KIM-compliant simulation code.

Transferability is quantified by estimating the energy error of a new configuration by using Gaussian process regression to interpolate between errors of known configurations.

sd b sbg f hSSSS SSSSSSSSSSS

2

Energy error per atom (eV)

Test

0 1.6 3.2 4.8 6.4-1.0

Si3

Si2

hcp

fcc

graphite

bc8

sc

bcc

sh

diamond

P

P

P

P

P

P

P

P

P

P

T

T

T

T

T

T

T

T

T

T

Energy error per atom (eV)

0 1.6 3.2 4.8 6.4-1.0

Si5FSP

Si5FTB

Si5ETB

Si4tetrahedron

Si4rhombus

Si4square

Si4 cct

Si4chain

Si4linear

Si3linear

P

P

P

P

P

P

P

P

P

P

T

T

T

T

T

T

T

T

T

T

Energy error per atom (eV)

0 1.6 3.2 4.8 6.4-1.0

Si(111)

Si(100)(2x1)

Si(100)(1x1)

hexagonalinterstitial

tetrahedralinterstitial

vacancy

Si6pent. pyr.

Si6octahedron

Si5pentagon

P

P

P

P

P

P

P

P

P

T

T

T

T

T

T

T

T

T

EDIP TBD

SW TBD

Tersoff meam

FIG. 1. (color online). Predictions of the GPR for six common silicon EPs: Tersoff (T2), Stillinger-Weber, EDIP, TBD, TBD,and TBD. The colored bars indicate the GPR prediction for the total energy error of each EP for the test configurations listed.For the purpose of comparing different test configurations, the total energy error has been normalized by the number of atomspresent in each test. The black intervals indicate the 95% confidence interval corresponding to each GPR prediction. Thewhite bars indicate the true energy error of each EP (again normalized by the number of atoms), computed by subtractingthe actual DFT energy from the energy predicted by the EP, for each test configuration. For each test configuration, a boxed“P” indicates the EP which is predicted to have the lowest energy error in absolute value, while a boxed “T” indicates the EPwhich truly has the lowest energy error.

2

Energy error per atom (eV)

Test

0 1.6 3.2 4.8 6.4-1.0

Si3

Si2

hcp

fcc

graphite

bc8

sc

bcc

sh

diamond

P

P

P

P

P

P

P

P

P

P

T

T

T

T

T

T

T

T

T

T

Energy error per atom (eV)

0 1.6 3.2 4.8 6.4-1.0

Si5FSP

Si5FTB

Si5ETB

Si4tetrahedron

Si4rhombus

Si4square

Si4 cct

Si4chain

Si4linear

Si3linear

P

P

P

P

P

P

P

P

P

P

T

T

T

T

T

T

T

T

T

T

Energy error per atom (eV)

0 1.6 3.2 4.8 6.4-1.0

Si(111)

Si(100)(2x1)

Si(100)(1x1)

hexagonalinterstitial

tetrahedralinterstitial

vacancy

Si6pent. pyr.

Si6octahedron

Si5pentagon

P

P

P

P

P

P

P

P

P

T

T

T

T

T

T

T

T

T

EDIP TBD

SW TBD

Tersoff meam

FIG. 1. (color online). Predictions of the GPR for six common silicon EPs: Tersoff (T2), Stillinger-Weber, EDIP, TBD, TBD,and TBD. The colored bars indicate the GPR prediction for the total energy error of each EP for the test configurations listed.For the purpose of comparing different test configurations, the total energy error has been normalized by the number of atomspresent in each test. The black intervals indicate the 95% confidence interval corresponding to each GPR prediction. Thewhite bars indicate the true energy error of each EP (again normalized by the number of atoms), computed by subtractingthe actual DFT energy from the energy predicted by the EP, for each test configuration. For each test configuration, a boxed“P” indicates the EP which is predicted to have the lowest energy error in absolute value, while a boxed “T” indicates the EPwhich truly has the lowest energy error.

M

MO_394669891912_001MO_142799717516_001MO_884343146310_001MO_748534961139_001MO_212700056563_001MO_104891429740_001MO_179025990738_001MO_977363131043_001

Sim Mod

Models are tested against a user-extendible set of calculations for well-defined material properties using an automated processing pipeline.

Page 27: The OpenKIM testing framework for interatomic potentials ...lammps.sandia.gov/workshops/Aug17/pdf/tadmor.pdf · The OpenKIM testing framework for interatomic potentials NSF CDI and

Ellad B. Tadmor (University of Minnesota)

https://openkim.org

27

Start here if you are new to KIM

Become a member to get updates and vote on KIM policy