def initialize(self):
""" Perform basic initializations """
# set the particles to None
self.particles = None
# default SPH kernel
self.default_kernel = CubicSplineKernel(dim=self.dim)
# flag to use OpenCL
self.with_cl = False
# mapping between operation id's and SPHOperations
self.operation_dict = {}
# Order of precedence for the SPHOperations
self.order = []
# solver time and iteration count
self.t = 0
self.count = 0
self.execute_commands = None
# list of functions to be called before and after an integration step
self.pre_step_functions = []
self.post_step_functions = []
# default output printing frequency
self.pfreq = 100
# Integer identifying the type of kernel correction to use
self.kernel_correction = -1
# the process id for parallel runs
self.pid = None
# set the default rank to 0
self.rank = 0
# set the default mode to serial
self.in_parallel = False
# default function to dynamically compute time step
self.time_step_function = TimeStep()
# arrays to print output
self.arrays_to_print = []
# the default parallel output mode
self.parallel_output_mode = "collected"
# default particle properties to print
self.print_properties = ['x','u','m','h','p','e','rho',]
if self.dim > 1:
self.print_properties.extend(['y','v'])
if self.dim > 2:
self.print_properties.extend(['z','w'])
# flag to print all arrays
self.detailed_output = False
# output filename
self.fname = self.__class__.__name__
# output drectory
self.output_directory = self.fname+'_output'
class Solver(object):
""" Base class for all PySPH Solvers
**Attributes**
- particles -- the particle arrays to operate on
- integrator_type -- the class of the integrator. This may be one of any
defined in solver/integrator.py
- kernel -- the kernel to be used throughout the calculations. This may
need to be modified to handle several kernels.
- operation_dict -- an internal structure indexing the operation id and
the corresponding operation as a dictionary
- order -- a list of strings specifying the order of an SPH simulation.
- t -- the internal time step counter
- pre_step_functions -- a list of functions to be performed before stepping
- post_step_functions -- a list of functions to execute after stepping
- pfreq -- the output print frequency
- dim -- the dimension of the problem
- kernel_correction -- flag to indicate type of kernel correction.
Defaults to -1 for no correction
- pid -- the processor id if running in parallel
- eps -- the epsilon value to use for XSPH stepping.
Defaults to -1 for no XSPH
"""
def __init__(self, dim, integrator_type):
self.integrator_type = integrator_type
self.dim = dim
self.eps = -1
self.cl_integrator_types = {EulerIntegrator:CLEulerIntegrator}
self.initialize()
def initialize(self):
""" Perform basic initializations """
# set the particles to None
self.particles = None
# default SPH kernel
self.default_kernel = CubicSplineKernel(dim=self.dim)
# flag to use OpenCL
self.with_cl = False
# mapping between operation id's and SPHOperations
self.operation_dict = {}
# Order of precedence for the SPHOperations
self.order = []
# solver time and iteration count
self.t = 0
self.count = 0
self.execute_commands = None
# list of functions to be called before and after an integration step
self.pre_step_functions = []
self.post_step_functions = []
# default output printing frequency
self.pfreq = 100
# Integer identifying the type of kernel correction to use
self.kernel_correction = -1
# the process id for parallel runs
self.pid = None
# set the default rank to 0
self.rank = 0
# set the default mode to serial
self.in_parallel = False
# default function to dynamically compute time step
self.time_step_function = TimeStep()
# arrays to print output
self.arrays_to_print = []
# the default parallel output mode
self.parallel_output_mode = "collected"
# default particle properties to print
self.print_properties = ['x','u','m','h','p','e','rho',]
if self.dim > 1:
self.print_properties.extend(['y','v'])
if self.dim > 2:
self.print_properties.extend(['z','w'])
# flag to print all arrays
self.detailed_output = False
# output filename
self.fname = self.__class__.__name__
# output drectory
self.output_directory = self.fname+'_output'
def switch_integrator(self, integrator_type):
""" Change the integrator for the solver """
if self.particles == None:
raise RuntimeError, "There are no particles!"
if self.with_cl:
self.integrator_type = self.cl_integrator_types[integrator_type]
else:
self.integrator_type = integrator_type
self.setup(self.particles)
def add_operation_step(self, types, xsph=False, eps=0.5):
""" Specify an acceptable list of types to step
Parameters
----------
types : a list of acceptable types eg Fluid, Solid
Notes
-----
The types are defined in base/particle_types.py
"""
updates = ['x','y','z'][:self.dim]
id = 'step'
self.add_operation(SPHIntegration(
PositionStepping, on_types=types, updates=updates, id=id,
kernel=None)
)
def add_operation_xsph(self, eps, hks=False):
""" Set the XSPH operation if requested
Parameters
----------
eps : the epsilon value to use for XSPH stepping
Notes
-----
The position stepping operation must be defined. This is because
the XSPH operation is setup for those arrays that need stepping.
The smoothing kernel used for this operation is the CubicSpline
"""
assert eps > 0, 'Invalid value for XSPH epsilon: %f' %(eps)
self.eps = eps
# create the xsph stepping operation
id = 'xsph'
err = "position stepping function does not exist!"
assert self.operation_dict.has_key('step'), err
types = self.operation_dict['step'].on_types
updates = self.operation_dict['step'].updates
self.add_operation(SPHIntegration(
XSPHCorrection.withargs(eps=eps, hks=hks), from_types=types,
on_types=types, updates=updates, id=id, kernel=self.default_kernel)
)
def add_operation(self, operation, before=False, id=None):
""" Add an SPH operation to the solver.
Parameters
----------
operation : the operation (:class:`SPHOperation`) to add
before : flag to indicate insertion before an id. Defaults to False
id : The id where to insert the operation. Defaults to None
Notes
-----
An SPH operation typically represents a single equation written
in SPH form. SPHOperation is defined in solver/sph_equation.py
The id for the operation must be unique. An error is raised if an
operation with the same id exists.
Similarly, an error is raised if an invalid 'id' is provided
as an argument.
Examples
--------
(1)
>>> solver.add_operation(operation)
This appends an operation to the existing list.
(2)
>>> solver.add_operation(operation, before=False, id=someid)
Add an operation after an existing operation with id 'someid'
(3)
>>> solver.add_operation(operation, before=True, id=soleid)
Add an operation before the operation with id 'someid'
"""
err = 'Operation %s exists!'%(operation.id)
assert operation.id not in self.order, err
assert operation.id not in self.operation_dict.keys()
self.operation_dict[operation.id] = operation
if id:
msg = 'The specified operation doesnt exist'
assert self.operation_dict.has_key(id), msg + ' in the calcs dict!'
assert id in self.order, msg + ' in the order list!'
if before:
self.order.insert(self.order.index(id), operation.id)
else:
self.order.insert(self.order.index(id)+1, operation.id)
else:
self.order.append(operation.id)
def replace_operation(self, id, operation):
""" Replace an operation.
Parameters
----------
id : the operation with id to replace
operation : The replacement operation
Notes
-----
The id to replace is taken from the provided operation.
An error is raised if the provided operation does not exist.
"""
msg = 'The specified operation doesnt exist'
assert self.operation_dict.has_key(id), msg + ' in the op dict!'
assert id in self.order, msg + ' in the order list!'
self.operation_dict.pop(id)
self.operation_dict[operation.id] = operation
idx = self.order.index(id)
self.order.insert(idx, operation.id)
self.order.remove(id)
def remove_operation(self, id_or_operation):
""" Remove an operation with id
Parameters
----------
id_or_operation : the operation to remove
Notes
-----
Remove an operation with either the operation object or the
operation id.
An error is raised if the operation is invalid.
"""
if type(id_or_operation) == str:
id = id_or_operation
else:
id = id_or_operation.id
assert id in self.operation_dict.keys(), 'id doesnt exist!'
assert id in self.order, 'id doesnt exist!'
self.order.remove(id)
self.operation_dict.pop(id)
def set_order(self, order):
""" Install a new order
The order determines the manner in which the operations are
executed by the integrator.
The new order and existing order should match else, an error is raised
"""
for equation_id in order:
msg = '%s in order list does not exist!'%(equation_id)
assert equation_id in self.order, msg
assert equation_id in self.operation_dict.keys(), msg
self.order = order
def setup_position_step(self):
""" Setup the position stepping for the solver """
pass
def setup(self, particles=None):
""" Setup the solver.
The solver's processor id is set if the in_parallel flag is set
to true.
The order of the integrating calcs is determined by the solver's
order attribute.
This is usually called at the start of a PySPH simulation.
By default, the kernel correction manager is set for all the calcs.
"""
if particles:
self.particles = particles
self.particles.kernel = self.default_kernel
# instantiate the Integrator
self.integrator = self.integrator_type(particles, calcs=[])
# setup the SPHCalc objects for the integrator
for equation_id in self.order:
operation = self.operation_dict[equation_id]
if operation.kernel is None:
operation.kernel = self.default_kernel
calcs = operation.get_calcs(particles, operation.kernel)
self.integrator.calcs.extend(calcs)
if self.with_cl:
self.integrator.setup_integrator(self.cl_context)
else:
self.integrator.setup_integrator()
# Setup the kernel correction manager for each calc
calcs = self.integrator.calcs
particles.correction_manager = KernelCorrectionManager(
calcs, self.kernel_correction)
def add_print_properties(self, props):
""" Add a list of properties to print """
for prop in props:
if not prop in self.print_properties:
self.print_properties.append(prop)
def append_particle_arrrays(self, arrays):
""" Append the particle arrays to the existing particle arrays """
if not self.particles:
print 'Warning!, particles not defined'
return
for array in self.particles.arrays:
array_name = array.name
for arr in arrays:
if array_name == arr.name:
array.append_parray(arr)
self.setup(self.particles)
def set_final_time(self, tf):
""" Set the final time for the simulation """
self.tf = tf
def set_time_step(self, dt):
""" Set the time step to use """
self.dt = dt
def set_print_freq(self, n):
""" Set the output print frequency """
self.pfreq = n
def set_arrays_to_print(self, array_names=None):
available_arrays = [array.name for array in self.particles.arrays]
if array_names:
for name in array_names:
if not name in available_arrays:
raise RuntimeError("Array %s not availabe"%(name))
array = self.particles.get_named_particle_array(name)
self.arrays_to_print.append(array)
else:
self.arrays_to_print = self.particles.arrays
def set_output_fname(self, fname):
""" Set the output file name """
self.fname = fname
def set_output_printing_level(self, detailed_output):
""" Set the output printing level """
self.detailed_output = detailed_output
def set_output_directory(self, path):
""" Set the output directory """
self.output_directory = path
def set_kernel_correction(self, kernel_correction):
""" Set the kernel correction manager for each calc """
self.kernel_correction = kernel_correction
for id in self.operation_dict:
self.operation_dict[id].kernel_correction=kernel_correction
def set_parallel_output_mode(self, mode="collected"):
"""Set the default solver dump mode in parallel.
The available modes are:
collected : Collect array data from all processors on root and
dump a single file.
distributed : Each processor dumps a file locally.
"""
self.parallel_output_mode = mode
def set_cl(self, with_cl=False):
""" Set the flag to use OpenCL
This option must be set after all operations are created so that
we may switch the default SPHCalcs to CLCalcs.
The solver must also setup an appropriate context which is used
to setup the ParticleArrays on the device.
"""
self.with_cl = with_cl
if with_cl:
if not HAS_CL:
raise RuntimeWarning, "PyOpenCL not found!"
for equation_id in self.order:
operation = self.operation_dict[equation_id]
# set the type of calc to use for the operation
operation.calc_type = CLCalc
# HACK. THE ONLY CL INTEGRATOR IS EULERINTEGRATOR
#self.integrator_type = self.cl_integrator_types[
# self.integrator_type]
self.integrator_type = CLEulerIntegrator
# Setup the OpenCL context
self.setup_cl()
def set_command_handler(self, callable, command_interval=1):
""" set the `callable` to be called at every `command_interval` iteration
the `callable` is called with the solver instance as an argument
"""
self.execute_commands = callable
self.command_interval = command_interval
def solve(self, show_progress=False):
""" Solve the system
Notes
-----
Pre-stepping functions are those that need to be called before
the integrator is called.
Similarly, post step functions are those that are called after
the stepping within the integrator.
"""
dt = self.dt
bt = (self.tf - self.t)/1000.0
bcount = 0.0
bar = PBar(1001, show=show_progress)
self.dump_output(dt, *self.print_properties)
# set the time for the integrator
self.integrator.time = self.t
while self.t < self.tf:
self.t += dt
self.count += 1
# update the particles explicitly
self.particles.update()
# perform any pre step functions
for func in self.pre_step_functions:
func.eval(self)
# compute the local time step
if not self.with_cl:
dt = self.time_step_function.compute_time_step(self)
# compute the global time step
dt = self.compute_global_time_step(dt)
logger.info("Time %f, time step %f, rank %d"%(self.t, dt,
self.rank))
# perform the integration and update the time
self.integrator.integrate(dt)
self.integrator.time += dt
# update the time for all arrays
self.update_particle_time()
# perform any post step functions
for func in self.post_step_functions:
func.eval(self)
# dump output
if self.count % self.pfreq == 0:
self.dump_output(dt, *self.print_properties)
bcount += self.dt/bt
while bcount > 0:
bar.update()
bcount -= 1
if self.execute_commands is not None:
if self.count % self.command_interval == 0:
self.execute_commands(self)
bar.finish()
def update_particle_time(self):
for array in self.particles.arrays:
array.set_time(self.t)
def compute_global_time_step(self, dt):
if self.particles.in_parallel:
props = {'dt':dt}
glb_min, glb_max = self.particles.get_global_min_max(props)
return glb_min['dt']
else:
return dt
def dump_output(self, dt, *print_properties):
""" Print output based on level of detail required
The default detail level (low) is the integrator's calc's update
property for each named particle array.
The higher detail level dumps all particle array properties.
Format:
-------
A single file named as: <fname>_<rank>_<count>.npz
The output file contains the following fields:
solver_data : Solver related data like time step, time and
iteration count. These are used to resume a simulation.
arrays : A dictionary keyed on particle array names and with
particle properties as value.
version : The version number for this format of file
output. The current version number is 1
Example:
--------
data = load('foo.npz')
version = data['version']
dt = data['solver_data']['dt']
t = data['solver_data']['t']
array = data['arrays'][array_name].astype(object)
array['x']
"""
if self.with_cl:
self.particles.read_from_buffer()
fname = self.fname + '_'
props = {"arrays":{}, "solver_data":{}}
cell_size = None
if not self.with_cl:
cell_size = self.particles.cell_manager.cell_size
_fname = os.path.join(self.output_directory,
fname + str(self.count) +'.npz')
if self.detailed_output:
for array in self.particles.arrays:
props["arrays"][array.name]=array.get_property_arrays(all=True)
else:
for array in self.particles.arrays:
props["arrays"][array.name]=array.get_property_arrays(all=False)
# Add the solver data
props["solver_data"]["dt"] = dt
props["solver_data"]["t"] = self.t
props["solver_data"]["count"] = self.count
if self.parallel_output_mode == "collected" and self.in_parallel:
comm = self.comm
arrays = props["arrays"]
numarrays = len(arrays)
array_names = arrays.keys()
# gather the data from all processors
collected_data = comm.gather(arrays, root=0)
if self.rank == 0:
props["arrays"] = {}
size = comm.Get_size()
# concatenate the arrays
for array_name in array_names:
props["arrays"][array_name] = {}
_props = collected_data[0][array_name].keys()
for prop in _props:
prop_arr = numpy.concatenate( [collected_data[pid][array_name][prop] for pid in range(size)] )
props["arrays"][array_name][prop] = prop_arr
savez(_fname, version=1, **props)
else:
savez(_fname, version=1, **props)
def load_output(self, count):
""" Load particle data from dumped output file.
Parameters
----------
count : string
The iteration time from which to load the data. If time is
'?' then list of available data files is returned else
the latest available data file is used
Notes
-----
Data is loaded from the :py:attr:`output_directory` using the same format
as stored by the :py:meth:`dump_output` method.
Proper functioning required that all the relevant properties of arrays be
dumped
"""
# get the list of available files
available_files = [i.rsplit('_',1)[1][:-4] for i in os.listdir(self.output_directory) if i.startswith(self.fname) and i.endswith('.npz')]
if count == '?':
return sorted(set(available_files), key=int)
else:
if not count in available_files:
msg = """File with iteration count `%s` does not exist"""%(count)
msg += "\nValid iteration counts are %s"%(sorted(set(available_files), key=int))
#print msg
raise IOError(msg)
array_names = [pa.name for pa in self.particles.arrays]
# load the output file
data = load(os.path.join(self.output_directory,
self.fname+'_'+str(count)+'.npz'))
arrays = [ data["arrays"][i] for i in array_names ]
# set the Particle's arrays
self.particles.arrays = arrays
# call the particle's initialize
self.particles.initialize()
self.t = float(data["solver_data"]['t'])
self.count = int(data["solver_data"]['count'])
def setup_cl(self):
""" Setup the OpenCL context and other initializations """
if HAS_CL:
platform = cl.get_platforms()[0]
self.cl_context = cl.Context(platform.get_devices())
def get_options(self, opt_parser):
""" Implement this to add additional options for the application """
pass
def setup_solver(self, options=None):
""" Implement the basic solvers here
All subclasses of Solver may implement this function to add the
necessary operations for the problem at hand.
Look at solver/fluid_solver.py for an example.
Parameters
----------
options : dict
options set by the user using commandline (there is no guarantee
of existence of any key)
"""
pass
