picassodev/picasso

Particle-in-cell library based on Cabana and Kokkos

Picasso

picasso's Issues

APIC for non-velocity quantities

Need an APIC implementation to advect quantities that are not just velocity.

Tensor and TensorViewWrapper for Rank > 2

• Implementation of higher rank tensor field types using variadic template type.
  • Re-write rank-2 Tensor as a specialization, possibly Vector as rank-1.
• Implementation of corresponding field ViewWrappers.

Deep Copy Operation for Batched Linear Algebra

A deep_copy(lhs,rhs) function needs to be added to BatchedLinearAlgebra to ensure that deep copies always occur when needed instead of relying on potentially confusing assignment operator syntax.

Scalar conversion operator for matrix/vector expressions

Our batched linear algebra interface needs a scalar conversion operator for MatrixExpression<1,1> and VectorExpression<1>.

DDMPM in Picasso

This issue concerns the implementation of the dual domain material point method (DDMPM) in Picasso.
DDMPM scores a few numerical advantages over the classical MPM, namely, improved accuracy and stability, especially in the vicinity of contact discontinuities, by reducing cell crossing noise.

A few sub-steps for a robust implementation are required:

• A distribution coefficient algorithm (DCA) for reducing small node mass instabilities. This requires the definition of nodal transfer coefficients, $C_{li}$. See Eq. (41) in the Zhang et al. paper.
• Modified shape function gradient calculation. This may be represented by a series of two consecutive stencil operations on the nodes.
• Incorporation of modified shape function gradient in the velocity (momentum) update.

Return particle scalars by reference

Replace ParticleInit with Cabana

Documentation

• README (build, run, test) @lebuller
• CONTRIBUTING @streeve
• Example (reimplementing dam break) @kwitaechong
• Performance tests? @streeve

Random seed for particle initialization

Picasso::initializeParticles and Picasso::initializeSurfaceParticles should accept a seed parameter to allow a user to specify a fixed seed for the Kokkos::Random_XorShift64_Pool pool. Otherwise, the behavior should default to initializing the pool with a random seed.

Add CI

• GitHub actions #3
• Cache boost in GHA #22
• Jenkins CUDA #9
• Jenkins HIP

Shared random number generator utility functions

Instead of hard-coding seed generation and state-pool creation from Kokkos:: random number generators, a set of utility functions in the Picasso:: namespace should be created to facilitate their use.

Replace ParticleList with Cabana

Quadratic and Cubic PolyPIC Implementation

• Quadratic Mathematica derivation
• Quadratic implementation
• Cubic Mathematica derivation
• Cubic implementation

2D Particle Infrastructure

2D base grid infrastructure has been largely added. Particle infrastructure (initialization, interpolation, I/O, etc.) is also needed.

Fix indexing/memory issue in Tensor3 wrapper

When indexing along the view wrapper for a Tensor3, there appears to be duplicated memory issue where setting values in certain indices will cause those values to be reproduced across separate indices.
i.e. when creating a wrapper for a 3x3x7 Tensor3 Field, filling the values across (All, All, 0) leads to some of the values on (All, All, 3) and (All, All, 6) to be erroneously filled at the same time.

Boundary Particle Data Structure

Boundary particles are need to implement boundary conditions on top of #37