DJUICE.jl

Differentiable JUlia ICE model

Overview

DJUICE.jl is a Julia package designed for differentiable ice sheet modeling, leveraging the power of Enzyme.jl for automatic differentiation. This package employs the Finite Element method (FEM) and follows the structure of the ice-sheet and Sea-level System Model (ISSM), which is the C++ counterpart for ice sheet modeling.

Features

• Differentiable ice sheet modeling using Enzyme.jl.
• Finite Element method implementation for ice numerical sheet modeling.
• Based on the well-established ISSM framework.

Installation

To install DJUICE.jl, you can use the Julia package manager. In your Julia REPL, run:

using Pkg
Pkg.add("DJUICE")

Usage

Here is a simple example of how to use DJUICE.jl:

using DJUICE

# Initialize model
md = model()

# Create mesh
md = triangle(md,issmdir()*"/test/Exp/Square.exp",50000.)
md = setmask(md,"all","")

#Geometry
hmin=300.
hmax=1000.
ymin=minimum(md.mesh.y)
ymax=maximum(md.mesh.y)
xmin=minimum(md.mesh.x)
xmax=maximum(md.mesh.x)
md.geometry.thickness = hmax .+ (hmin-hmax)*(md.mesh.y .- ymin)./(ymax-ymin) .+ 0.1*(hmin-hmax)*(md.mesh.x .- xmin)./(xmax-xmin)
md.geometry.base      = -md.materials.rho_ice/md.materials.rho_water*md.geometry.thickness
md.geometry.surface   = md.geometry.base+md.geometry.thickness
md.geometry.bed       = md.geometry.base .-10

#Initial velocity
md.initialization.vx=zeros(md.mesh.numberofvertices)
md.initialization.vy=zeros(md.mesh.numberofvertices)

# Physical parameters
md.materials.rheology_B=1.815730284801701e+08*ones(md.mesh.numberofvertices)
md.materials.rheology_n=3*ones(md.mesh.numberofelements)
md.friction.coefficient=20*ones(md.mesh.numberofvertices)
md.friction.p=ones(md.mesh.numberofvertices)
md.friction.q=ones(md.mesh.numberofvertices)

# Numerical tolerances
md.stressbalance.restol=0.05
md.stressbalance.reltol=0.05
md.stressbalance.abstol=NaN

#Boundary conditions
md.stressbalance.spcvx = NaN*ones(md.mesh.numberofvertices)
md.stressbalance.spcvy = NaN*ones(md.mesh.numberofvertices)
pos = findall(md.mesh.vertexonboundary)
md.stressbalance.spcvx[pos] .= 0.0
md.stressbalance.spcvy[pos] .= 0.0

# Solve
md=solve(md,:Stressbalance)

For detailed tutorials and examples, please refer to the documentation.

Documentation

Comprehensive documentation is available to help you get started and make the most out of DJUICE.jl. It includes tutorials, API references, and examples. Access the documentation here.

Contributing

Contributions are welcome! If you find a bug or have a feature request, please open an issue on our GitHub repository. If you want to contribute code, please fork the repository and submit a pull request.

License

DJUICE.jl is released under the MIT License. See the LICENSE file for more details.

Acknowledgements

This project is inspired by the ice-sheet and Sea-level System Model (ISSM). Special thanks to the developers of Enzyme.jl for providing an excellent tool for automatic differentiation in Julia.

Authors:

• Mathieu Morlighem, Dartmouth College, USA
• Cheng Gong, Dartmouth College, USA