Use of ChatGPT 4 for coding new YADE DEM constitutive laws

Hello,

for the first sight, it looks good :-)
I will have closer look later, as I am interested in GPT capabilities.

> // Note: You will need to implement the specific calculations for the model
> // ...

this is actual GPT output? In fact, it is the most important and challenging part of the model implementation..

Cheers
Jan

Hi,

I asked it to continue implementing the model with exponential temperature dependence (it was lacking the nature of temperature dependence as it does not exist in the original burgers formulation).

Here is the result:

Header:

#pragma once
#include<yade/pkg/dem/CohesiveFrictionalContactLaw.hpp>
#include<yade/pkg/dem/ScGeom.hpp>
#include<yade/pkg/dem/FrictPhys.hpp>
#include<yade/pkg/dem/ThermalState.hpp>

class TempDependentBurgersViscoElasticModel: public CohFrictMat {
public:
    TempDependentBurgersViscoElasticModel(Real young, Real poisson, Real frictionAngle, Real density, Real cohesion, Real viscousDamping, Real viscosity, Real tempRef, Real tempExpFactor);
    virtual ~TempDependentBurgersViscoElasticModel();

    // Temperature reference for the model
    Real tempRef;

    // Temperature exponential factor
    Real tempExpFactor;

    // Viscosity for the viscoelastic component of the model
    Real viscosity;

    YADE_CLASS_BASE_DOC_ATTRS_CTOR(TempDependentBurgersViscoElasticModel, CohFrictMat, "Temperature-dependent Burger's viscoelastic model inheriting from CohFrictMat",
        ((Real, viscousDamping, 0, ,"Viscous damping for the viscoelastic component of the model"))
        ((Real, tempRef, 298.15, ,"Reference temperature for the model"))
        ((Real, viscosity, 0, ,"Viscosity for the viscoelastic component of the model"))
        ((Real, tempExpFactor, 0, ,"Temperature exponential factor for the temperature-dependent tangential force")),
        /* ctor */ TempDependentBurgersViscoElasticModel(young, poisson, frictionAngle, density, cohesion, viscousDamping, viscosity, tempRef, tempExpFactor); );
};
REGISTER_SERIALIZABLE(TempDependentBurgersViscoElasticModel);

class TempDependentBurgersViscoElasticContactLaw: public Law2_ScGeom_FrictPhys_CundallStrack {
public:
    virtual void go(shared_ptr<IGeom>& ig, shared_ptr<IPhys>& ip, Interaction* contact);
    YADE_CLASS_BASE_DOC(TempDependentBurgersViscoElasticContactLaw, Law2_ScGeom_FrictPhys_CundallStrack, "Contact law for the temperature-dependent Burger's viscoelastic model");
};
REGISTER_SERIALIZABLE(TempDependentBurgersViscoElasticContactLaw);

CCP file:

#include "TempDependentBurgersViscoElastic.hpp"

TempDependentBurgersViscoElasticModel::TempDependentBurgersViscoElasticModel(Real young, Real poisson, Real frictionAngle, Real density, Real cohesion, Real viscousDamping, Real viscosity, Real tempRef, Real tempExpFactor)
    : CohFrictMat(young, poisson, frictionAngle, density, cohesion)
    , viscousDamping(viscousDamping)
    , viscosity(viscosity)
    , tempRef(tempRef)
    , tempExpFactor(tempExpFactor) {
}

TempDependentBurgersViscoElasticModel::~TempDependentBurgersViscoElasticModel() {
}

YADE_PLUGIN((TempDependentBurgersViscoElasticModel));

void TempDependentBurgersViscoElasticContactLaw::go(shared_ptr<IGeom>& ig, shared_ptr<IPhys>& ip, Interaction* contact) {
// Cast the geometry and physical parameters to the correct types
ScGeom* geom = static_cast<ScGeom*>(ig.get());
FrictPhys* phys = static_cast<FrictPhys*>(ip.get());

// Get the associated bodies and materials
Body* b1 = Body::byId(contact->getId1(), scene);
Body* b2 = Body::byId(contact->getId2(), scene);
TempDependentBurgersViscoElasticModel* mat1 = static_cast<TempDependentBurgersViscoElasticModel*>(b1->material.get());
TempDependentBurgersViscoElasticModel* mat2 = static_cast<TempDependentBurgersViscoElasticModel*>(b2->material.get());

// Compute the normal force based on Hooke's law
Real kn = 2 * phys->kn * geom->radius / (geom->radius + geom->radius);
Real Fn = kn * geom->penetrationDepth;

// Compute the tangential force based on a simplified version of the Burger's model
Real kt = 2 * phys->kt * geom->radius / (geom->radius + geom->radius);
Real viscosity = 0.5 * (mat1->viscosity + mat2->viscosity);
Real viscousDamping = 0.5 * (mat1->viscousDamping + mat2->viscousDamping);

Vector3r relVel = b1->state->vel - b2->state->vel;
Vector3r relAngVel = b1->state->angVel - b2->state->angVel;

Vector3r relTangentialVel = relVel - geom->normal.dot(relVel) * geom->normal;
Vector3r relTangentialAngVel = geom->radius * 0.5 * (relAngVel.cross(geom->normal));

Vector3r relTangentialTotalVel = relTangentialVel + relTangentialAngVel;
Vector3r tangentialForce = -(kt * geom->uT + viscosity * relTangentialTotalVel);

// Get the temperatures from the thermal state
shared_ptr<ThermalState> ts1 = YADE_PTR_CAST<ThermalState>(b1->state);
shared_ptr<ThermalState> ts2 = YADE_PTR_CAST<ThermalState>(b2->state);
Real avgTemp = 0.5 * (ts1->temp + ts2->temp);

// Apply temperature-dependent exponential factor
Real tempExpFactor = 0.5 * (mat1->tempExpFactor + mat2->tempExpFactor);
Real tempRef = 0.5 * (mat1->tempRef + mat2->tempRef);
Real tempFactor = std::exp(tempExpFactor * (avgTemp - tempRef));
tangentialForce *= tempFactor;

// Apply Coulomb friction law
Real maxTangentialForce = phys->tangensOfFrictionAngle * Fn;
if (tangentialForce.norm() > maxTangentialForce) {
    tangentialForce = tangentialForce.normalized() * maxTangentialForce;
}

Vector3r normalForce = geom->normal * Fn;

// Apply the forces to the bodies
scene->forces.addForce(contact->getId1(), normalForce + tangentialForce);
scene->forces.addForce(contact->getId2(), -(normalForce + tangentialForce));
scene->forces.addTorque(contact->getId1(), geom->radius * 0.5 * tangentialForce.cross(geom->normal));
scene->forces.addTorque(contact->getId2(), -geom->radius * 0.5 * tangentialForce.cross(geom->normal));

geom->uT = geom->uT - geom->rotate(tangentialForce / kt);

}

YADE_PLUGIN((TempDependentBurgersViscoElasticContactLaw));

Hope it is more helpful now.

Hello,

If you don't mind, may I ask for your guidance on how you would instruct GPT-4 to write the script mentioned above? Specifically, I am interested in how you would enable GPT-4 to access the variable names and locate the required Hpp files in the given code. I would greatly appreciate your response.
Thank you very much!

xue

Sure,

here is in general the prompt i used:

"can you write me c++ code (header and ccp files) for new temperature dependent cohesive burgers visco elastic model for Yade Dem ?, inherit from cohfrictmat and ThermalState. implement exponential temperature dependence"

Thank you very much for your response!
xue

Hello,

I have tried the result.

TLTR: not so good actually..

As is my so fart experience with ChatGPT, all that glitters is not gold.
For the first sight, it looks relatively OK.
For more closer look, there are maaany problems to make it even compile (I gave up after not so short time)
- wrong includes,
- non-existent includes
- using non-existent variables
- redeclaration of variables and functions
- ...

Concerning actual implementation (TempDependentBurgersViscoElasticContactLaw::go), you have to check yourself if it computes it correctly.
Specifically the tangentialForce value.

Maybe just asking it for the implementation of Law2::go functions would have better results, but currently it produces non-compilable code (therefore the actual value is questionable).

Cheers
Jan

thanks! i will try to prompt it with the source code and see if there are better results.