upwind dissipation on matrix form

This commit is contained in:
Magnus Ulimoen 2020-06-15 22:28:53 +02:00
parent ad6564eeb1
commit f7a30ac1cc
2 changed files with 48 additions and 5 deletions

View File

@ -38,3 +38,10 @@ print("B+")
print(Bplus)
print("B-")
print(Bminus)
print()
print("SA = Aplus - Aminus")
print(Aplus - Aminus)
print("SB = Bplus - Bminus")
print(Bplus - Bminus)

View File

@ -1,20 +1,21 @@
use super::Float;
use sbp::operators::SbpOperator2d;
use sbp::operators::{SbpOperator2d, UpwindOperator2d};
use sbp::utils::sparse_sparse_outer_product;
fn eye(n: usize) -> sprs::CsMat<Float> {
sprs::CsMat::eye(n)
}
/// Implicit version of the system
/// C u_{t+1} = u_t
pub fn implicit_matrix(rhs: sprs::CsMatView<Float>, dt: Float) -> sprs::CsMat<Float> {
let n = rhs.rows();
let i_kyx = sprs::CsMat::eye(n);
let f = rhs.map(|x| x * dt);
&i_kyx - &f
&eye(n) - &f
}
/// Assumes self boundaries
pub fn rhs_matrix(op: &dyn SbpOperator2d, ny: usize, nx: usize) -> sprs::CsMat<Float> {
let eye = |n: usize| sprs::CsMat::eye(n);
let fluxes = {
let d1_x = op.op_eta().diff_matrix(nx);
let d1_y = op.op_xi().diff_matrix(ny);
@ -197,6 +198,41 @@ pub fn rhs_matrix(op: &dyn SbpOperator2d, ny: usize, nx: usize) -> sprs::CsMat<F
&fluxes + &(&(&sat_west + &sat_east) + &(&sat_north + &sat_south))
}
/// RHS with some additional dissipation from the upwind operator
pub fn rhs_matrix_with_upwind_dissipation(
op: &dyn UpwindOperator2d,
ny: usize,
nx: usize,
) -> sprs::CsMat<Float> {
let rhs = rhs_matrix(op.as_sbp(), ny, nx);
let diss_x = {
let diss_x = UpwindOperator2d::op_xi(op).diss_matrix(nx);
let diss_x = sparse_sparse_outer_product(eye(ny).view(), diss_x.view());
let sa = {
let mut sa = sprs::CsMat::zero((3, 3));
sa.insert(1, 1, 1.0);
sa.insert(2, 2, 1.0);
sa
};
sparse_sparse_outer_product(sa.view(), diss_x.view())
};
let diss_y = {
let diss_y = UpwindOperator2d::op_eta(op).diss_matrix(ny);
let diss_y = sparse_sparse_outer_product(diss_y.view(), eye(nx).view());
let sa = {
let mut sa = sprs::CsMat::zero((3, 3));
sa.insert(0, 0, 1.0);
sa.insert(1, 1, 1.0);
sa
};
sparse_sparse_outer_product(sa.view(), diss_y.view())
};
&rhs + &(&diss_x + &diss_y)
}
#[test]
fn dummy() {
let ny = 16;