JaxPM/jaxpm/painting.py
2024-10-22 17:30:33 -04:00

237 lines
8.9 KiB
Python

from functools import partial
import jax
import jax.lax as lax
import jax.numpy as jnp
from jax.sharding import PartitionSpec as P
from jaxpm.distributed import (autoshmap, get_halo_size, halo_exchange,
slice_pad, slice_unpad, fft3d, ifft3d)
from jaxpm.kernels import cic_compensation, fftk
from jaxpm.painting_utils import gather, scatter
def cic_paint_impl(grid_mesh, displacement, weight=None):
""" Paints positions onto mesh
mesh: [nx, ny, nz]
displacement field: [nx, ny, nz, 3]
"""
part_shape = displacement.shape
positions = jnp.stack(jnp.meshgrid(jnp.arange(part_shape[0]),
jnp.arange(part_shape[1]),
jnp.arange(part_shape[2]),
indexing='ij'),
axis=-1) + displacement
positions = positions.reshape([-1, 3])
positions = jnp.expand_dims(positions, 1)
floor = jnp.floor(positions)
connection = jnp.array([[[0, 0, 0], [1., 0, 0], [0., 1, 0], [0., 0, 1],
[1., 1, 0], [1., 0, 1], [0., 1, 1], [1., 1, 1]]])
neighboor_coords = floor + connection
kernel = 1. - jnp.abs(positions - neighboor_coords)
kernel = kernel[..., 0] * kernel[..., 1] * kernel[..., 2]
if weight is not None:
kernel = jnp.multiply(jnp.expand_dims(weight, axis=-1), kernel)
neighboor_coords = jnp.mod(
neighboor_coords.reshape([-1, 8, 3]).astype('int32'),
jnp.array(grid_mesh.shape))
dnums = jax.lax.ScatterDimensionNumbers(update_window_dims=(),
inserted_window_dims=(0, 1, 2),
scatter_dims_to_operand_dims=(0, 1,
2))
mesh = lax.scatter_add(grid_mesh, neighboor_coords,
kernel.reshape([-1, 8]), dnums)
return mesh
@partial(jax.jit, static_argnums=(2, 3, 4))
def cic_paint(grid_mesh, positions, halo_size=0, weight=None, sharding=None):
halo_size, halo_extents = get_halo_size(halo_size, sharding)
grid_mesh = slice_pad(grid_mesh, halo_size, sharding)
gpu_mesh = sharding.mesh if sharding is not None else None
spec = sharding.spec if sharding is not None else P()
grid_mesh = autoshmap(cic_paint_impl,
gpu_mesh=gpu_mesh,
in_specs=(spec, spec, P()),
out_specs=spec)(grid_mesh, positions, weight)
grid_mesh = halo_exchange(grid_mesh,
halo_extents=halo_extents,
halo_periods=(True, True))
grid_mesh = slice_unpad(grid_mesh, halo_size, sharding)
return grid_mesh
def cic_read_impl(mesh, displacement):
""" Paints positions onto mesh
mesh: [nx, ny, nz]
displacement: [nx,ny,nz, 3]
"""
# Compute the position of the particles on a regular grid
part_shape = displacement.shape
positions = jnp.stack(jnp.meshgrid(jnp.arange(part_shape[0]),
jnp.arange(part_shape[1]),
jnp.arange(part_shape[2]),
indexing='ij'),
axis=-1) + displacement
positions = positions.reshape([-1, 3])
positions = jnp.expand_dims(positions, 1)
floor = jnp.floor(positions)
connection = jnp.array([[[0, 0, 0], [1., 0, 0], [0., 1, 0], [0., 0, 1],
[1., 1, 0], [1., 0, 1], [0., 1, 1], [1., 1, 1]]])
neighboor_coords = floor + connection
kernel = 1. - jnp.abs(positions - neighboor_coords)
kernel = kernel[..., 0] * kernel[..., 1] * kernel[..., 2]
neighboor_coords = jnp.mod(neighboor_coords.astype('int32'),
jnp.array(mesh.shape))
return (mesh[neighboor_coords[..., 0], neighboor_coords[..., 1],
neighboor_coords[..., 3]] * kernel).sum(axis=-1).reshape(
displacement.shape[:-1])
@partial(jax.jit, static_argnums=(2, 3))
def cic_read(mesh, displacement, halo_size=0, sharding=None):
halo_size, halo_extents = get_halo_size(halo_size, sharding=sharding)
mesh = slice_pad(mesh, halo_size, sharding=sharding)
mesh = halo_exchange(mesh,
halo_extents=halo_extents,
halo_periods=(True, True))
gpu_mesh = sharding.mesh if sharding is not None else None
spec = sharding.spec if sharding is not None else P()
displacement = autoshmap(cic_read_impl,
gpu_mesh=gpu_mesh,
in_specs=(spec, spec),
out_specs=spec)(mesh, displacement)
return displacement
def cic_paint_2d(mesh, positions, weight):
""" Paints positions onto a 2d mesh
mesh: [nx, ny]
positions: [npart, 2]
weight: [npart]
"""
positions = jnp.expand_dims(positions, 1)
floor = jnp.floor(positions)
connection = jnp.array([[0, 0], [1., 0], [0., 1], [1., 1]])
neighboor_coords = floor + connection
kernel = 1. - jnp.abs(positions - neighboor_coords)
kernel = kernel[..., 0] * kernel[..., 1]
if weight is not None:
kernel = kernel * weight[..., jnp.newaxis]
neighboor_coords = jnp.mod(
neighboor_coords.reshape([-1, 4, 2]).astype('int32'),
jnp.array(mesh.shape))
dnums = jax.lax.ScatterDimensionNumbers(update_window_dims=(),
inserted_window_dims=(0, 1),
scatter_dims_to_operand_dims=(0,
1))
mesh = lax.scatter_add(mesh, neighboor_coords, kernel.reshape([-1, 4]),
dnums)
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, 2))
def cic_paint_dx(displacements, halo_size=0, sharding=None):
halo_size, halo_extents = get_halo_size(halo_size, sharding=sharding)
gpu_mesh = sharding.mesh if sharding is not None else None
spec = sharding.spec if sharding is not None else P()
grid_mesh = autoshmap(partial(cic_paint_dx_impl, halo_size=halo_size),
gpu_mesh=gpu_mesh,
in_specs=spec,
out_specs=spec)(displacements)
grid_mesh = halo_exchange(grid_mesh,
halo_extents=halo_extents,
halo_periods=(True, True))
grid_mesh = slice_unpad(grid_mesh, halo_size, sharding)
return grid_mesh
def cic_read_dx_impl(grid_mesh, halo_size):
halo_x, _ = halo_size[0]
halo_y, _ = halo_size[1]
original_shape = [
dim - 2 * halo[0] for dim, halo in zip(grid_mesh.shape, halo_size)
]
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 + halo_x, b + halo_y, c], axis=-1)
pmid = pmid.reshape([-1, 3])
return gather(pmid, jnp.zeros_like(pmid),
grid_mesh).reshape(original_shape)
@partial(jax.jit, static_argnums=(1, 2))
def cic_read_dx(grid_mesh, halo_size=0, sharding=None):
# return mesh
halo_size, halo_extents = get_halo_size(halo_size, sharding=sharding)
grid_mesh = slice_pad(grid_mesh, halo_size, sharding=sharding)
grid_mesh = halo_exchange(grid_mesh,
halo_extents=halo_extents,
halo_periods=(True, True))
gpu_mesh = sharding.mesh if sharding is not None else None
spec = sharding.spec if sharding is not None else P()
displacements = autoshmap(partial(cic_read_dx_impl, halo_size=halo_size),
gpu_mesh=gpu_mesh,
in_specs=(spec),
out_specs=spec)(grid_mesh)
return displacements
def compensate_cic(field):
"""
Compensate for CiC painting
Args:
field: input 3D cic-painted field
Returns:
compensated_field
"""
delta_k = fft3d(field)
kvec = fftk(delta_k)
delta_k = cic_compensation(kvec) * delta_k
return ifft3d(delta_k)