tasks.py

# ***************************************************************************
# *   Copyright (c) 2017 Markus Hovorka <m.hovorka@live.de>                 *
# *                                                                         *
# *   This file is part of the FreeCAD CAx development system.              *
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# *   GNU Library General Public License for more details.                  *
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__title__ = "FreeCAD FEM solver Elmer tasks"
__author__ = "Markus Hovorka"
__url__ = "https://www.freecadweb.org"

## \addtogroup FEM
#  @{

import cmath
import os
import os.path
import subprocess
from platform import system

import FreeCAD

from . import writer
from .. import run
from .. import settings
from femtools import femutils
from femtools import membertools


class Check(run.Check):

    def run(self):
        self.pushStatus("Checking analysis...\n")
        if (self.check_mesh_exists()):
            self.checkMeshType()
        self.check_material_exists()
        self.checkEquations()

    def checkMeshType(self):
        mesh = membertools.get_single_member(self.analysis, "Fem::FemMeshObject")
        if not femutils.is_of_type(mesh, "Fem::FemMeshGmsh"):
            self.report.error(
                "Unsupported type of mesh. "
                "Mesh must be created with gmsh.")
            self.fail()
            return False
        return True

    def checkEquations(self):
        equations = self.solver.Group
        if not equations:
            self.report.error(
                "Solver has no equations. "
                "Add at least one equation.")
            self.fail()


class Prepare(run.Prepare):

    def run(self):
        # TODO print working dir to report console
        self.pushStatus("Preparing input files...\n")
        if self.testmode:
            # test mode: neither gmsh, nor elmergrid nor elmersolver binaries needed
            FreeCAD.Console.PrintMessage("Machine testmode: {}\n".format(self.testmode))
            w = writer.Writer(self.solver, self.directory, True)
        else:
            FreeCAD.Console.PrintLog("Machine testmode: {}\n".format(self.testmode))
            w = writer.Writer(self.solver, self.directory)
        try:
            w.write_solver_input()
            self.checkHandled(w)
            self.pushStatus("Writing solver input completed.")
        except writer.WriteError as e:
            self.report.error(str(e))
            self.fail()
        except IOError:
            self.report.error("Can't access working directory.")
            self.fail()

    def checkHandled(self, w):
        handled = w.getHandledConstraints()
        allConstraints = membertools.get_member(self.analysis, "Fem::Constraint")
        for obj in set(allConstraints) - handled:
            self.report.warning("Ignored constraint %s." % obj.Label)


class Solve(run.Solve):

    def run(self):
        # on rerun the result file will not deleted before starting the solver
        # if the solver fails, the existing result from a former run file will be loaded
        # TODO: delete result file (may be delete all files which will be recreated)
        self.pushStatus("Executing solver...\n")
        binary = settings.get_binary("ElmerSolver")
        if binary is not None:
            # if ELMER_HOME is not set, set it.
            # Needed if elmer is compiled but not installed on Linux
            # http://www.elmerfem.org/forum/viewtopic.php?f=2&t=7119
            # https://stackoverflow.com/questions/1506010/how-to-use-export-with-python-on-linux
            # TODO move retrieving the param to solver settings module
            elparams = FreeCAD.ParamGet("User parameter:BaseApp/Preferences/Mod/Fem/Elmer")
            elmer_env = elparams.GetBool("SetElmerEnvVariables", False)
            if elmer_env is True and system() == "Linux" and "ELMER_HOME" not in os.environ:
                solvpath = os.path.split(binary)[0]
                if os.path.isdir(solvpath):
                    os.environ["ELMER_HOME"] = solvpath
                    os.environ["LD_LIBRARY_PATH"] = "$LD_LIBRARY_PATH:{}/modules".format(solvpath)
            # hide the popups on Windows
            if system() == "Windows":
                self._process = subprocess.Popen(
                    [binary],
                    cwd=self.directory,
                    stdout=subprocess.PIPE,
                    stderr=subprocess.PIPE,
                    startupinfo=femutils.startProgramInfo("hide")
                )
            else:
                self._process = subprocess.Popen(
                    [binary],
                    cwd=self.directory,
                    stdout=subprocess.PIPE,
                    stderr=subprocess.PIPE
                )
            self.signalAbort.add(self._process.terminate)
            output = self._observeSolver(self._process)
            self._process.communicate()
            self.signalAbort.remove(self._process.terminate)
            if not self.aborted:
                self._updateOutput(output)
        else:
            self.report.error("ElmerSolver binary not found.")
            self.pushStatus("Error: ElmerSolver binary has not been found!")
            self.fail()

    def _updateOutput(self, output):
        if self.solver.ElmerOutput is None:
            self._createOutput()
        # check if eigenmodes were calculated and if so append them to output
        output = self._calculateEigenfrequencies(output)
        self.solver.ElmerOutput.Text = output

    def _createOutput(self):
        self.solver.ElmerOutput = self.analysis.Document.addObject(
            "App::TextDocument", self.solver.Name + "Output")
        self.solver.ElmerOutput.Label = self.solver.Label + "Output"
        # App::TextDocument has no Attribute ReadOnly
        # TODO check if the attribute has been removed from App::TextDocument
        # self.solver.ElmerOutput.ReadOnly = True
        self.analysis.addObject(self.solver.ElmerOutput)
        self.solver.Document.recompute()

    def _calculateEigenfrequencies(self, output):
        # takes the EigenSolve results and performs the calculation
        # sqrt(aResult) / 2*PI but with aResult as complex number

        # first search the output file for the results
        OutputList = output.split("\n")
        modeNumber = 0
        modeCount = 0
        real = 0
        imaginary = 0
        haveImaginary = False
        FrequencyList = []
        for line in OutputList:
            LineList = line.split(" ")
            if (len(LineList) > 1) \
             and (LineList[0] == "EigenSolve:") \
             and (LineList[1] == "Computed"):
                # we found a result and take now the next LineList[2] lines
                modeCount = int(LineList[2])
                modeNumber = modeCount
                continue
            if modeCount > 0:
                for LineString in reversed(LineList):
                    # the output of Elmer may vary, we only know the last float
                    # is the imaginary and second to last float the real part
                    if self._isNumber(LineString):
                        if not haveImaginary:
                            imaginary = float(LineString)
                            haveImaginary = True
                        else:
                            real = float(LineString)
                            break
                eigenFreq = complex(real, imaginary)
                haveImaginary = False
                # now we can perform the calculation
                eigenFreq = cmath.sqrt(eigenFreq) / (2 * cmath.pi)
                # create an output line
                FrequencyList.append("Mode " + str(modeNumber - modeCount + 1) \
                    + ": " + str(eigenFreq.real) + " Hz")
                modeCount = modeCount - 1
        if modeNumber > 0:
            # push the results and append to output
            self.pushStatus("\n\nEigenfrequency results:")
            output = output + "\n\nEigenfrequency results:"
            for i in range(0, modeNumber):
                output = output + "\n" + FrequencyList[i]
                self.pushStatus("\n" + FrequencyList[i])
            self.pushStatus("\n")
        return output

    def _isNumber(self, string):
        try:
            float(string)
            return True
        except ValueError:
            return False

class Results(run.Results):

    def run(self):
        if self.solver.ElmerResult is None:
            self._createResults()
        postPath = self._getResultFile()
        if postPath is None:
            self.pushStatus("\nNo result file was created.\n")
            self.fail()
            return
        self.solver.ElmerResult.read(postPath)
        self.solver.ElmerResult.scale(1000)
        self.solver.ElmerResult.getLastPostObject().touch()
        self.solver.Document.recompute()

    def _createResults(self):
        self.solver.ElmerResult = self.analysis.Document.addObject(
            "Fem::FemPostPipeline", self.solver.Name + "Result")
        self.solver.ElmerResult.Label = self.solver.Label + "Result"
        self.analysis.addObject(self.solver.ElmerResult)
        # to assure the user sees something, set the default to Surface
        self.solver.ElmerResult.ViewObject.DisplayMode = "Surface"

    def _getResultFile(self):
        postPath = None
        # elmer post file path changed with version x.x
        # see https://forum.freecadweb.org/viewtopic.php?f=18&t=42732
        # workaround
        possible_post_file_0 = os.path.join(self.directory, "case0001.vtu")
        possible_post_file_t = os.path.join(self.directory, "case_t0001.vtu")
        if os.path.isfile(possible_post_file_0):
            postPath = possible_post_file_0
        elif os.path.isfile(possible_post_file_t):
            postPath = possible_post_file_t
        else:
            self.report.error("Result file not found.")
            self.fail()
        return postPath

##  @}