collocated_checkerboard_tail Namespace Reference

Functions
	radius ()
	sdf_on (cx, cy, cz, shift_h, h)
	old_stop (m, tol=1e-6, every=5)
	new_stop (m)
	geom (Ns)
	run (tag, N, beta, solver, scheme, steps, shift=0.0, opts="")
	tail (m, floor=1e-11)
	analyze (tag)
	structure (tag)
	stops (tag)

Variables
	L
	RHO
	MU
	F
	PHI
	OUT = os.environ.get("PROBE_OUT", "probe_out")
	HERE = os.path.dirname(os.path.abspath(__file__))
	cmd
	a

Detailed Description

The slow (pi,0,0) pressure-checkerboard tail of the collocated steady march (2026-10-01).

Instrument behind doc/collocated_invisible_subspace.md §11. It marches the case of
study_avg_velocity_spheres.py (one sphere per periodic unit cell, phi = 0.125, centred on a grid
vertex, rho = mu = f = 1, nu dt / h^2 = beta, MG-PCG rtol 1e-8, velocity cap 200) and records per
step <u_x>, rms(du) and the rms of the fluid pressure increment, plus the last four iterates, so
that the asymptotic contraction rate and the spatial structure of the slow component can be read.

  geom N1,N2,..                    fluid-centre / crossing-fraction census of the sphere per N
  run TAG N beta stag|col auto|ghost|gauge-exact STEPS [shift_h] [opts]
                                   march STEPS steps; shift_h moves the centre by (s,s,s) h;
                                   opts (comma list): norot (PM I ablation), prtol12 (rtol 1e-12)
                                   -> $PROBE_OUT/TAG.npz (default ./probe_out)
  analyze TAG..                    tail rate per step, its amplitude, the extrapolated limit
  structure TAG..                  where the slow component lives: wall band, Fourier content
  stops TAG..                      replay the history through the study's old (5bcf353) and
                                   current stop tests: step and K bias against the limit

Run (from flow/, pool bounded): OMP_NUM_THREADS=4 OMP_PROC_BIND=false PYTHONPATH=<flow build>
python tests/study/collocated_checkerboard_tail.py run col16 16 6 col auto 800

Function Documentation

radius()

collocated_checkerboard_tail.radius

(

)

Definition at line 34 of file collocated_checkerboard_tail.py.

Referenced by geom(), and sdf_on().

sdf_on()

collocated_checkerboard_tail.sdf_on	(		cx,
			cy,
			cz,
			shift_h,
			h
	)

Definition at line 38 of file collocated_checkerboard_tail.py.

References radius().

Referenced by geom(), and run().

old_stop()

collocated_checkerboard_tail.old_stop	(		m,
			tol = 1e-6,
			every = 5
	)

The stop of study_avg_velocity_spheres.py at 5bcf353: |m_n - m_{n-5}| < tol |m_n|.

Definition at line 44 of file collocated_checkerboard_tail.py.

Referenced by stops().

new_stop()

collocated_checkerboard_tail.new_stop

(

m

)

The study's current march() replayed on a recorded history (-1 if it never stops).

Definition at line 55 of file collocated_checkerboard_tail.py.

Referenced by stops().

geom()

collocated_checkerboard_tail.geom

(

Ns

)

Definition at line 73 of file collocated_checkerboard_tail.py.

References radius(), and sdf_on().

run()

collocated_checkerboard_tail.run	(		tag,
			N,
			beta,
			solver,
			scheme,
			steps,
			shift = 0.0,
			opts = ""
	)

Definition at line 90 of file collocated_checkerboard_tail.py.

References mean(), and sdf_on().

tail()

collocated_checkerboard_tail.tail	(		m,
			floor = 1e-11
	)

(per-step rate, window, back-projected amplitude, geometric-extrapolated limit).

Definition at line 137 of file collocated_checkerboard_tail.py.

Referenced by analyze(), and stops().

analyze()

collocated_checkerboard_tail.analyze

(

tag

)

Definition at line 147 of file collocated_checkerboard_tail.py.

References tail().

structure()

collocated_checkerboard_tail.structure

(

tag

)

Where the last step's increment lives: wall band and Fourier content.

Definition at line 161 of file collocated_checkerboard_tail.py.

References mean().

stops()

collocated_checkerboard_tail.stops

(

tag

)

Definition at line 186 of file collocated_checkerboard_tail.py.

References new_stop(), old_stop(), and tail().

Variable Documentation

L

collocated_checkerboard_tail.L

Definition at line 29 of file collocated_checkerboard_tail.py.

RHO

collocated_checkerboard_tail.RHO

Definition at line 29 of file collocated_checkerboard_tail.py.

MU

collocated_checkerboard_tail.MU

Definition at line 29 of file collocated_checkerboard_tail.py.

F

collocated_checkerboard_tail.F

Definition at line 29 of file collocated_checkerboard_tail.py.

PHI

collocated_checkerboard_tail.PHI

Definition at line 29 of file collocated_checkerboard_tail.py.

OUT

collocated_checkerboard_tail.OUT = os.environ.get("PROBE_OUT", "probe_out")

Definition at line 30 of file collocated_checkerboard_tail.py.

HERE

collocated_checkerboard_tail.HERE = os.path.dirname(os.path.abspath(__file__))

Definition at line 31 of file collocated_checkerboard_tail.py.

cmd

collocated_checkerboard_tail.cmd

Definition at line 196 of file collocated_checkerboard_tail.py.

a

collocated_checkerboard_tail.a

Definition at line 196 of file collocated_checkerboard_tail.py.