implement distributed optimized cic_paint

This commit is contained in:
Wassim KABALAN 2024-07-18 12:39:15 +02:00
parent e62cd84cbd
commit 5775a37550
2 changed files with 286 additions and 7 deletions

View file

@ -5,14 +5,13 @@ import jax.lax as lax
import jax.numpy as jnp
from jax.sharding import PartitionSpec as P
from jaxpm.distributed import autoshmap
from jaxpm.distributed import (autoshmap, get_halo_size, halo_exchange,
slice_pad, slice_unpad)
from jaxpm.kernels import cic_compensation, fftk
from jaxpm.painting_utils import gather, scatter
@partial(autoshmap,
in_specs=(P('x', 'y'), P('x', 'y'), P('x', 'y')),
out_specs=P('x', 'y'))
def cic_paint(mesh, displacement, weight=None):
def cic_paint_impl(mesh, displacement, weight=None):
""" Paints positions onto mesh
mesh: [nx, ny, nz]
displacement field: [nx, ny, nz, 3]
@ -48,8 +47,22 @@ def cic_paint(mesh, displacement, weight=None):
return mesh
@partial(autoshmap, in_specs=(P('x', 'y'), P('x', 'y')), out_specs=P('x', 'y'))
def cic_read(mesh, displacement):
@partial(jax.jit, static_argnums=(2, ))
def cic_paint(mesh, positions, halo_size=0, weight=None):
halo_size, halo_extents = get_halo_size(halo_size)
mesh = slice_pad(mesh, halo_size)
mesh = autoshmap(cic_paint_impl,
in_specs=(P('x', 'y'), P('x', 'y'), P()),
out_specs=P('x', 'y'))(mesh, positions, weight)
mesh = halo_exchange(mesh,
halo_extents=halo_extents,
halo_periods=(True, True, True))
mesh = slice_unpad(mesh, halo_size)
return mesh
def cic_read_impl(mesh, displacement):
""" Paints positions onto mesh
mesh: [nx, ny, nz]
displacement: [nx,ny,nz, 3]
@ -79,6 +92,21 @@ def cic_read(mesh, displacement):
displacement.shape[:-1])
@partial(jax.jit, static_argnums=(2, ))
def cic_read(mesh, displacement, halo_size=0):
halo_size, halo_extents = get_halo_size(halo_size)
mesh = slice_pad(mesh, halo_size)
mesh = halo_exchange(mesh,
halo_extents=halo_extents,
halo_periods=(True, True, True))
displacement = autoshmap(cic_read_impl,
in_specs=(P('x', 'y'), P('x', 'y')),
out_specs=P('x', 'y'))(mesh, displacement)
return displacement
def cic_paint_2d(mesh, positions, weight):
""" Paints positions onto a 2d mesh
mesh: [nx, ny]
@ -108,6 +136,72 @@ def cic_paint_2d(mesh, positions, weight):
return mesh
def cic_paint_dx_impl(displacements, halo_size):
halo_x, _ = halo_size[0]
halo_y, _ = halo_size[1]
original_shape = displacements.shape
particle_mesh = jnp.zeros(original_shape[:-1], dtype='float32')
# Padding is forced to be zero in a single gpu run
a, b, c = jnp.meshgrid(jnp.arange(particle_mesh.shape[0]),
jnp.arange(particle_mesh.shape[1]),
jnp.arange(particle_mesh.shape[2]),
indexing='ij')
particle_mesh = jnp.pad(particle_mesh, halo_size)
pmid = jnp.stack([a + halo_x, b + halo_y, c], axis=-1)
pmid = pmid.reshape([-1, 3])
return scatter(pmid, displacements.reshape([-1, 3]), particle_mesh)
@partial(jax.jit, static_argnums=(1, ))
def cic_paint_dx(displacements, halo_size=0):
halo_size, halo_extents = get_halo_size(halo_size)
mesh = autoshmap(partial(cic_paint_dx_impl, halo_size=halo_size),
in_specs=(P('x', 'y')),
out_specs=P('x', 'y'))(displacements)
mesh = halo_exchange(mesh,
halo_extents=halo_extents,
halo_periods=(True, True, True))
mesh = slice_unpad(mesh, halo_size)
return mesh
def cic_read_dx_impl(mesh):
original_shape = mesh.shape
a, b, c = jnp.meshgrid(jnp.arange(original_shape[0]),
jnp.arange(original_shape[1]),
jnp.arange(original_shape[2]),
indexing='ij')
pmid = jnp.stack([a, b, c], axis=-1)
pmid = pmid.reshape([-1, 3])
return gather(pmid, jnp.zeros_like(pmid), mesh).reshape(original_shape)
@partial(jax.jit, static_argnums=(1, ))
def cic_read_dx(mesh, halo_size=0):
halo_size, halo_extents = get_halo_size(halo_size)
mesh = slice_pad(mesh, halo_size)
mesh = halo_exchange(mesh,
halo_extents=halo_extents,
halo_periods=(True, True, True))
displacements = autoshmap(cic_read_dx_impl,
in_specs=(P('x', 'y')),
out_specs=P('x', 'y'))(mesh)
return displacements
def compensate_cic(field):
"""
Compensate for CiC painting

185
jaxpm/painting_utils.py Normal file
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@ -0,0 +1,185 @@
import jax
import jax.numpy as jnp
from jax.lax import scan
def _chunk_split(ptcl_num, chunk_size, *arrays):
"""Split and reshape particle arrays into chunks and remainders, with the remainders
preceding the chunks. 0D ones are duplicated as full arrays in the chunks."""
chunk_size = ptcl_num if chunk_size is None else min(chunk_size, ptcl_num)
remainder_size = ptcl_num % chunk_size
chunk_num = ptcl_num // chunk_size
remainder = None
chunks = arrays
if remainder_size:
remainder = [x[:remainder_size] if x.ndim != 0 else x for x in arrays]
chunks = [x[remainder_size:] if x.ndim != 0 else x for x in arrays]
# `scan` triggers errors in scatter and gather without the `full`
chunks = [
x.reshape(chunk_num, chunk_size, *x.shape[1:])
if x.ndim != 0 else jnp.full(chunk_num, x) for x in chunks
]
return remainder, chunks
def enmesh(i1, d1, a1, s1, b12, a2, s2):
"""Multilinear enmeshing."""
i1 = jnp.asarray(i1)
d1 = jnp.asarray(d1)
a1 = jnp.float64(a1) if a2 is not None else jnp.array(a1, dtype=d1.dtype)
if s1 is not None:
s1 = jnp.array(s1, dtype=i1.dtype)
b12 = jnp.float64(b12)
if a2 is not None:
a2 = jnp.float64(a2)
if s2 is not None:
s2 = jnp.array(s2, dtype=i1.dtype)
dim = i1.shape[1]
neighbors = (jnp.arange(2**dim, dtype=i1.dtype)[:, jnp.newaxis] >>
jnp.arange(dim, dtype=i1.dtype)) & 1
if a2 is not None:
P = i1 * a1 + d1 - b12
P = P[:, jnp.newaxis] # insert neighbor axis
i2 = P + neighbors * a2 # multilinear
if s1 is not None:
L = s1 * a1
i2 %= L
i2 //= a2
d2 = P - i2 * a2
if s1 is not None:
d2 -= jnp.rint(d2 / L) * L # also abs(d2) < a2 is expected
i2 = i2.astype(i1.dtype)
d2 = d2.astype(d1.dtype)
a2 = a2.astype(d1.dtype)
d2 /= a2
else:
i12, d12 = jnp.divmod(b12, a1)
i1 -= i12.astype(i1.dtype)
d1 -= d12.astype(d1.dtype)
# insert neighbor axis
i1 = i1[:, jnp.newaxis]
d1 = d1[:, jnp.newaxis]
# multilinear
d1 /= a1
i2 = jnp.floor(d1).astype(i1.dtype)
i2 += neighbors
d2 = d1 - i2
i2 += i1
if s1 is not None:
i2 %= s1
f2 = 1 - jnp.abs(d2)
if s1 is None and s2 is not None: # all i2 >= 0 if s1 is not None
i2 = jnp.where(i2 < 0, s2, i2)
f2 = f2.prod(axis=-1)
return i2, f2
def _scatter_chunk(carry, chunk):
mesh, offset, cell_size, mesh_shape = carry
pmid, disp, val = chunk
spatial_ndim = pmid.shape[1]
spatial_shape = mesh.shape
# multilinear mesh indices and fractions
ind, frac = enmesh(pmid, disp, cell_size, mesh_shape, offset, cell_size,
spatial_shape)
# scatter
ind = tuple(ind[..., i] for i in range(spatial_ndim))
mesh = mesh.at[ind].add(val * frac)
carry = mesh, offset, cell_size, mesh_shape
return carry, None
def scatter(pmid,
disp,
mesh,
chunk_size=2**24,
val=1.,
offset=0,
cell_size=1.):
ptcl_num, spatial_ndim = pmid.shape
val = jnp.asarray(val)
mesh = jnp.asarray(mesh)
remainder, chunks = _chunk_split(ptcl_num, chunk_size, pmid, disp, val)
carry = mesh, offset, cell_size, mesh.shape
if remainder is not None:
carry = _scatter_chunk(carry, remainder)[0]
carry = scan(_scatter_chunk, carry, chunks)[0]
mesh = carry[0]
return mesh
def _chunk_cat(remainder_array, chunked_array):
"""Reshape and concatenate one remainder and one chunked particle arrays."""
array = chunked_array.reshape(-1, *chunked_array.shape[2:])
if remainder_array is not None:
array = jnp.concatenate((remainder_array, array), axis=0)
return array
def gather(pmid, disp, mesh, chunk_size=2**24, val=1, offset=0, cell_size=1.):
ptcl_num, spatial_ndim = pmid.shape
mesh = jnp.asarray(mesh)
val = jnp.asarray(val)
if mesh.shape[spatial_ndim:] != val.shape[1:]:
raise ValueError('channel shape mismatch: '
f'{mesh.shape[spatial_ndim:]} != {val.shape[1:]}')
remainder, chunks = _chunk_split(ptcl_num, chunk_size, pmid, disp, val)
carry = mesh, offset, cell_size, mesh.shape
val_0 = None
if remainder is not None:
val_0 = _gather_chunk(carry, remainder)[1]
val = scan(_gather_chunk, carry, chunks)[1]
val = _chunk_cat(val_0, val)
return val
def _gather_chunk(carry, chunk):
mesh, offset, cell_size, mesh_shape = carry
pmid, disp, val = chunk
spatial_ndim = pmid.shape[1]
spatial_shape = mesh.shape[:spatial_ndim]
chan_ndim = mesh.ndim - spatial_ndim
chan_axis = tuple(range(-chan_ndim, 0))
# multilinear mesh indices and fractions
ind, frac = enmesh(pmid, disp, cell_size, mesh_shape, offset, cell_size,
spatial_shape)
# gather
ind = tuple(ind[..., i] for i in range(spatial_ndim))
frac = jnp.expand_dims(frac, chan_axis)
val += (mesh.at[ind].get(mode='drop', fill_value=0) * frac).sum(axis=1)
return carry, val