fluid.py 3.12 KB
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from ctypes import *
import numpy
import signal
import os

dir_path = os.path.dirname(os.path.realpath(__file__))
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lib = CDLL(os.path.join(dir_path,"libmbfluid2.so"))
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signal.signal(signal.SIGINT, signal.SIG_DFL)


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BNDCB = CFUNCTYPE(None,c_int,POINTER(c_double),POINTER(c_double))
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class StrongBoundary(Structure):
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    _fields_ = [("tag",c_char_p),("field",c_int),("apply",BNDCB)]
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class fluid_problem :

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    def __init__(self, mesh_file_name, g, mu, rho, alpha, autoEpsilon, strong_boundaries):
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        nsb = len(strong_boundaries)
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        class Bnd :
            def __init__(self, b) :
                self._b = b
            def apply(self, n, xp, vp) :
                x = numpy.frombuffer(cast(xp, POINTER(int(n)*2*c_double)).contents).reshape([n,2])
                v = numpy.frombuffer(cast(vp, POINTER(int(n)*c_double)).contents)
                if callable(self._b) :
                    v[:] = self._b(x)
                else :
                    v[:] = self._b

        asb = (StrongBoundary*nsb)(*[StrongBoundary(i[0].encode(),i[1],BNDCB(Bnd(i[2]).apply)) for i in strong_boundaries])
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        self.asb = asb
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        lib.fluid_problem_new.restype = c_void_p
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        self._fp = c_void_p(lib.fluid_problem_new(mesh_file_name.encode(), c_double(g), c_double(mu), c_double(rho), c_double(alpha), c_bool(autoEpsilon), nsb, asb))
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        if self._fp == None :
            raise NameError("cannot create fluid problem")

    def __del__(self):
        if(self._fp != None) :
            lib.fluid_problem_free(self._fp)

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    def adapt_mesh(self, gradmin, gradmax, lcmin, autoEpsilon) :
        lib.fluid_problem_adapt_mesh(self._fp, c_double(gradmin), c_double(gradmax), c_double(lcmin), c_bool(autoEpsilon))
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    def export(self, output_dir, t, it) :
        lib.fluid_problem_export(self._fp, output_dir.encode(), c_double(t), c_int(it))

    def compute_node_force(self, dt) :
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        def np2c(a) :
            return c_void_p(a.ctypes.data)
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        forces = numpy.ndarray([self.n_particles,2],"d")
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        lib.fluid_problem_compute_node_particle_force(self._fp, c_double(dt), np2c(forces))
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        return forces

    def implicit_euler(self, dt) :
        lib.fluid_problem_implicit_euler(self._fp, c_double(dt))

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    def set_particles(self, mass, volume, position, velocity, elid=None):
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        def np2c(a) :
            return c_void_p(numpy.ascontiguousarray(a).ctypes.data)
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        def np2ci(a) :
            return c_void_p(numpy.require(a,"int","C").ctypes.data)
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        self.n_particles = mass.shape[0]
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        if elid is not None:
            lib.fluid_problem_set_particles(self._fp,c_int(mass.shape[0]),np2c(mass),np2c(volume),np2c(position),np2c(velocity),np2ci(elid))
        else :
            lib.fluid_problem_set_particles(self._fp,c_int(mass.shape[0]),np2c(mass),np2c(volume),np2c(position),np2c(velocity),None)

    def particle_element_id(self) :
        f = getattr(lib,"fluid_problem_particle_element_id")
        f.restype = c_void_p
        fs = getattr(lib,"fluid_problem_n_particles")
        fs.restype = c_int
        ptr = f(self._fp)
        size = fs(self._fp)
        buf = (size*c_int).from_address(ptr)
        return numpy.ctypeslib.as_array(buf)