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pm.py no longer uses global mesh

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This commit is contained in:
Wassim KABALAN 2024-10-22 12:09:50 -04:00
parent 56ffd263f6
commit 80c56dced5
1 changed files with 27 additions and 14 deletions
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41
jaxpm/pm.py
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@ -14,17 +14,23 @@ from jaxpm.kernels import (PGD_kernel, fftk, gradient_kernel, laplace_kernel,
from jaxpm.painting import cic_paint, cic_paint_dx, cic_read, cic_read_dx
def pm_forces(positions, mesh_shape=None, delta=None, r_split=0, halo_size=0):
def pm_forces(positions,
mesh_shape=None,
delta=None,
r_split=0,
halo_size=0,
sharding=None):
"""
Computes gravitational forces on particles using a PM scheme
"""
if mesh_shape is None:
assert (delta is not None
), "If mesh_shape is not provided, delta should be provided"
assert (delta is not None),\
"If mesh_shape is not provided, delta should be provided"
mesh_shape = delta.shape
if delta is None:
delta_k = fft3d(cic_paint_dx(positions, halo_size=halo_size))
delta_k = fft3d(
cic_paint_dx(positions, halo_size=halo_size, sharding=sharding))
else:
delta_k = fft3d(delta)
@ -35,7 +41,8 @@ def pm_forces(positions, mesh_shape=None, delta=None, r_split=0, halo_size=0):
# Computes gravitational forces
forces = jnp.stack([
cic_read_dx(ifft3d(gradient_kernel(kvec, i) * pot_k),
halo_size=halo_size) for i in range(3)
halo_size=halo_size,
sharding=sharding) for i in range(3)
],
axis=-1)
@ -77,20 +84,25 @@ def lpt2_source(mesh_size, initial_conditions):
return source
def lpt(cosmo, initial_conditions, a, halo_size=0):
def lpt(cosmo, initial_conditions, a, halo_size=0, sharding=None):
"""
Computes first order LPT displacement
"""
local_mesh_shape = (*get_local_shape(initial_conditions.shape), 3)
gpu_mesh = sharding.mesh if sharding is not None else None
spec = sharding.spec if sharding is not None else P()
local_mesh_shape = (*get_local_shape(initial_conditions.shape, sharding),
3)
displacement = autoshmap(
partial(jnp.zeros, shape=(local_mesh_shape), dtype='float32'),
gpu_mesh=gpu_mesh,
in_specs=(),
out_specs=P('x', 'y'))() # yapf: disable
out_specs=spec)() # yapf: disable
initial_force = pm_forces(displacement,
delta=initial_conditions,
halo_size=halo_size)
halo_size=halo_size,
sharding=sharding)
a = jnp.atleast_1d(a)
dx = growth_factor(cosmo, a) * initial_force
p = a**2 * growth_rate(cosmo, a) * jnp.sqrt(jc.background.Esqr(cosmo,
@ -133,12 +145,12 @@ def lpt2(cosmo, initial_conditions, dx, p, f, a, halo_size=0):
return dx, p, f
def linear_field(mesh_shape, box_size, pk, seed):
def linear_field(mesh_shape, box_size, pk, seed, sharding=None):
"""
Generate initial conditions.
"""
# Initialize a random field with one slice on each gpu
field = normal_field(mesh_shape, seed=seed)
field = normal_field(mesh_shape, seed=seed, sharding=sharding)
field = fft3d(field)
kvec = fftk(field)
kmesh = sum((kk / box_size[i] * mesh_shape[i])**2
@ -151,7 +163,7 @@ def linear_field(mesh_shape, box_size, pk, seed):
return field
def make_ode_fn(mesh_shape, halo_size=0):
def make_ode_fn(mesh_shape, halo_size=0, sharding=None):
def nbody_ode(state, a, cosmo):
"""
@ -159,8 +171,9 @@ def make_ode_fn(mesh_shape, halo_size=0):
"""
pos, vel = state
forces = pm_forces(pos, mesh_shape=mesh_shape,
halo_size=halo_size) * 1.5 * cosmo.Omega_m
forces = pm_forces(
pos, mesh_shape=mesh_shape, halo_size=halo_size,
sharding=sharding) * 1.5 * cosmo.Omega_m
# Computes the update of position (drift)
dpos = 1. / (a**3 * jnp.sqrt(jc.background.Esqr(cosmo, a))) * vel