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#
# Copyright 2019 Anton Khirnov <anton@khirnov.net>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
import os
import ctypes
import numpy as np
DIFF_COEFF_00 = 0
DIFF_COEFF_01 = 1
DIFF_COEFF_10 = 2
DIFF_COEFF_11 = 3
DIFF_COEFF_02 = 4
DIFF_COEFF_20 = 5
BC_TYPE_FIXVAL = 0
BC_TYPE_REFLECT = 1
BC_TYPE_FALLOFF = 2
BOUNDARY_0L = 0
BOUNDARY_0U = 1
BOUNDARY_1L = 2
BOUNDARY_1U = 3
ERR_DIVERGE = 0xff00
_doubleptr = ctypes.POINTER(ctypes.c_double)
if ctypes.sizeof(ctypes.c_void_p) == 8:
_ptrdiff_t = ctypes.c_int64
elif ctypes.sizeof(ctypes.c_void_p) == 4:
_ptrdiff_t = ctypes.c_int32
else:
raise NotImplementedError('Unsupported pointer size: %d' %\
ctypes.sizeof(ctypes.c_void_p))
def _wrap_array(obj, stride, len):
arr_np = np.ctypeslib.as_array(obj, (len, stride))
return arr_np[:, :len]
class SolveError(Exception):
errno = None
def __init__(self, errno):
super().__init__(self, 'Error solving the equation: %s (%d) ' % (os.strerror(errno), errno))
self.errno = errno
class _MG2DBoundary(ctypes.Structure):
_fields_ = [
("type", ctypes.c_int),
("val", _doubleptr),
("val_stride", ctypes.c_size_t),
]
class _MG2DDCBoundarySpec(ctypes.Structure):
_fields_ = [
("flags", ctypes.c_int),
("val", _doubleptr),
]
class _MG2DDiffCoeffs(ctypes.Structure):
_fields_ = [
("data", _doubleptr),
("stride", _ptrdiff_t),
("boundaries", _MG2DDCBoundarySpec * 4),
]
class _MG2DContext(ctypes.Structure):
_fields_ = [
("priv", ctypes.c_void_p),
("log_callback", ctypes.c_void_p),
("opaque", ctypes.c_void_p),
("domain_size", ctypes.c_size_t),
("step", ctypes.c_double * 2),
("fd_stencil", ctypes.c_size_t),
("boundaries", ctypes.POINTER(_MG2DBoundary) * 4),
("maxiter", ctypes.c_uint),
("tol", ctypes.c_double),
("nb_cycles", ctypes.c_uint),
("nb_relax_pre", ctypes.c_uint),
("nb_relax_post", ctypes.c_uint),
("u", _doubleptr),
("u_stride", _ptrdiff_t),
("rhs", _doubleptr),
("rhs_stride", _ptrdiff_t),
#("diff_coeffs", ctypes.POINTER(_MG2DDiffCoeffs) * 6),
("diff_coeffs", _doubleptr * 6),
("diff_coeffs_stride", _ptrdiff_t),
("nb_threads", ctypes.c_uint),
("cfl_factor", ctypes.c_double),
("log_level", ctypes.c_int),
("max_levels", ctypes.c_uint),
("max_exact_size", ctypes.c_size_t),
]
class Boundary:
type = None
lines = None
_arr = None
def __init__(self, val, val_stride, max_stencil, domain_size):
self._arr = np.ctypeslib.as_array(val, (val_stride * max_stencil,))
self.lines = []
for i in range(max_stencil):
line_offset = i * (val_stride - 1)
line_len = domain_size + 2 * i
self.lines.append(self._arr[line_offset:line_offset + line_len])
class DiffCoeffsBoundarySpec:
_mg2dctx = None
_dc_idx = None
_bnd_idx = None
def __init__(self, mg2dctx, dc_idx, bnd_idx):
self._mg2dctx = mg2dctx
self._dc_idx = dc_idx
self._bnd_idx = bnd_idx
@property
def val(self):
dc = self._mg2dctx.contents.diff_coeffs[self._dc_idx].contents
return np.ctypeslib.as_array(dc.boundaries[self._bnd_idx].val, (self._mg2dctx.contents.domain_size,))
@property
def flags(self):
dc = self._mg2dctx.contents.diff_coeffs[self._dc_idx].contents
return dc.boundaries[self._bnd_idx].flags
@flags.setter
def flags(self, val):
dc = self._mg2dctx.contents.diff_coeffs[self._dc_idx].contents
dc.boundaries[self._bnd_idx].flags = val
class DiffCoeffs:
boundaries = None
_mg2dctx = None
_idx = None
def __init__(self, mg2dctx, idx):
self._mg2dctx = mg2dctx
self._idx = idx
#self.boundaries = []
#for i in range(4):
# self.boundaries.append(DiffCoeffsBoundarySpec(mg2dctx, idx, i))
@property
def data(self):
#dc = self._mg2dctx.contents.diff_coeffs[self._idx].contents
#return _wrap_array(dc.data, dc.stride, self._mg2dctx.contents.domain_size)
data = self._mg2dctx.contents.diff_coeffs[self._idx]
stride = self._mg2dctx.contents.diff_coeffs_stride
return _wrap_array(data, stride, self._mg2dctx.contents.domain_size)
def __getitem__(self, key):
return self.data[key]
def __setitem__(self, key, val):
self.data[key] = val
class Solver:
diff_coeffs = None
boundaries = None
_libmg2d = None
_mg2dctx = None
def __init__(self, domain_size):
self._lib_init()
self._mg2dctx = self._libmg2d.mg2d_solver_alloc(domain_size)
if self._mg2dctx is None:
raise MemoryError('Error allocating the solver')
self.diff_coeffs = []
for i in range(len(self._mg2dctx.contents.diff_coeffs)):
self.diff_coeffs.append(DiffCoeffs(self._mg2dctx, i))
self.boundaries = []
for i, bnd in enumerate(self._mg2dctx.contents.boundaries):
boundary = Boundary(bnd.contents.val, bnd.contents.val_stride,
self._libmg2d.mg2d_max_fd_stencil(), domain_size)
self.boundaries.append(boundary)
def _lib_init(self):
self._libmg2d = ctypes.CDLL('libmg2d.so')
solver_alloc = self._libmg2d.mg2d_solver_alloc
solver_alloc.argtypes = [ctypes.c_size_t]
solver_alloc.restype = ctypes.POINTER(_MG2DContext)
solver_free = self._libmg2d.mg2d_solver_free
solver_free.argtypes = [ctypes.POINTER(ctypes.POINTER(_MG2DContext))]
solver_free.restype = None
solver_solve = self._libmg2d.mg2d_solve
solver_solve.argtypes = [ctypes.POINTER(_MG2DContext)]
solver_solve.restype = ctypes.c_int
solver_print_stats = self._libmg2d.mg2d_print_stats
solver_print_stats.argtypes = [ctypes.POINTER(_MG2DContext), ctypes.c_char_p]
solver_print_stats.restype = None
max_fd_stencil = self._libmg2d.mg2d_max_fd_stencil
max_fd_stencil.restype = ctypes.c_uint
def __del__(self):
if self._mg2dctx:
free = self._libmg2d.mg2d_solver_free
addr_mg2dctx = ctypes.cast((ctypes.addressof(self._mg2dctx)), free.argtypes[0])
free(addr_mg2dctx)
self._mg2dctx = None
@property
def u(self):
return _wrap_array(self._mg2dctx.contents.u, self._mg2dctx.contents.u_stride,
self._mg2dctx.contents.domain_size)
@property
def rhs(self):
return _wrap_array(self._mg2dctx.contents.rhs, self._mg2dctx.contents.rhs_stride,
self._mg2dctx.contents.domain_size)
def solve(self, **kwargs):
for arg, value in kwargs.items():
try:
self._mg2dctx.contents.__setattr__(arg, value)
except TypeError as e:
# try assigning items of an iterable
try:
for i, it in enumerate(value):
self._mg2dctx.contents.__getattribute__(arg)[i] = it
except:
raise e
for i, bnd in enumerate(self.boundaries):
if bnd.type is None:
raise ValueError('Boundary %d not set' % i)
self._mg2dctx.contents.boundaries[i].contents.type = bnd.type
ret = self._libmg2d.mg2d_solve(self._mg2dctx)
if ret < 0:
raise SolveError(-ret)
def print_stats(self):
log_level = self._mg2dctx.contents.log_level
self._mg2dctx.contents.log_level = 0x40
self._libmg2d.mg2d_print_stats(self._mg2dctx, ctypes.c_char_p(None))
self._mg2dctx.contents.log_level = log_level
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