Unit tests

The unit tests pin the building blocks below the solver: the eigensystems, the fluxes and Riemann solvers, the positivity limiter, the WENO tables and weights, and the library pieces FLUME relies on (the tree lookup, the quadtree seam exchange, the Poisson solvers). Each device twin (_fnl) also asserts the device result equal to the host one.

FLUME

Sources in src/tests/flume/unit/.

Test	What it pins
test_flume_euler_library (+ _fnl)	Euler eigensystem, flux, Roe average, split consistency; RS(q, q) = f(q) for LLF/HLL/HLLC, HLLC exact on a contact, positive first-order updates; the si descaler of planar and static states within ${10}^8$ of the largest (host); device = host
test_flume_mhd_library (+ _fnl)	MHD, GLM and EGLM eigensystems (including degenerate states), fluxes, auxiliary variables, cyclic invariance; the si descaler of planar, field-free and static states within ${10}^8$ of the largest; ${\alpha }_f$, ${\alpha }_s$ to full relative accuracy at high and low β with $\mathbf{B}$ near the normal, against quadruple precision (#79) (host); device = host
test_flume_mhd_riemann (+ _fnl)	MHD LLF/HLL/HLLD without cleaning, with GLM and with EGLM: consistency, HLLD exact on contact, tangential and rotational discontinuities, cyclic invariance bitwise, positive updates, EGLM = GLM bitwise at $\psi =0$; device = host
test_flume_positivity	PV-0, the limiter on random admissible states with perturbed fluxes (Euler, MHD, EGLM): every limited update positive and above the relative floor, the limiter needed and acting; a NaN or infinite high-order flux replaced by the backbone flux; inadmissible face ghosts blended above the floors, every other value untouched; a cell with a 2:1 seam face (mean donor-state backbone) admissible for any seam factor up to its own, and not without the limiter
test_flume_weno_interpolation (+ _fnl)	WENO interpolation tables: exactness, convergence, device = host for both weights (js, si); the reconstruction tables unchanged; the si weights scale-covariant bitwise on the device
test_flume_weno_weights	NV-1 of issue #49: with [weno] weights = si, WENO($2^{n}v$) = $2^n$ WENO($v$) bitwise for every scheme, both tables, random stencils from ${10}^{-12}$ to ${10}^{12}$; the js weights fail it (negative control); quadratic data reproduced by both; zero data stay zero

fobis build --mode test-flume-<name>-gnu                         # host
fobis build --mode test-flume-<name>-fnl-nvf --varset local_nvf  # device twin

Library tests used by the FLUME cases

Test	Sources	What it pins	Case
test_tree_closest_block	src/tests/amr/	the tree lookup of the seam peers on binary trees, quadtrees and octrees, including a single-block tree (#54)	multi-realm runs
test_quadtree_seam_ghost (+ -fnl-nvf)	src/tests/amr/	the 2:1 seam exchange on a linear field: octree, quadtree nk = 4 and nk = 1, 1 to 3 ranks; the device exchange equal to the CPU one, bit for bit (#46)	quadtree AMR
test_poisson_fft (+ -fnl-nvf)	src/tests/poisson/	the FFT Poisson solver, periodic and isolated (SV-2, SV-6)	FFT Poisson solver, isolated solver
test_poisson_mg	src/tests/poisson/	the multigrid Poisson solver on AMR grids (SV-9)	multigrid on AMR

Build modes: test-tree-closest-block-gnu, test-quadtree-seam-ghost-gnu (-fnl-nvf), test-poisson-fft-gnu (-fnl-nvf), test-poisson-mg-gnu.