Exemplo n.º 1
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    def set_pos(self, otherpoint, value):
        """Used to set the position of this point w.r.t. another point.

        Parameters
        ==========

        value : Vector
            The vector which defines the location of this point
        point : Point
            The other point which this point's location is defined relative to

        Examples
        ========

        >>> from sympy.physics.mechanics import Point, ReferenceFrame
        >>> N = ReferenceFrame('N')
        >>> p1 = Point('p1')
        >>> p2 = Point('p2')
        >>> p1.set_pos(p2, 10 * N.x)
        >>> p1.pos_from(p2)
        10*N.x

        """

        value = _check_vector(value)
        self._check_point(otherpoint)
        self._pos_dict.update({otherpoint: value})
        otherpoint._pos_dict.update({self: -value})
Exemplo n.º 2
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    def set_vel(self, frame, value):
        """Sets the velocity Vector of this Point in a ReferenceFrame.

        Parameters
        ==========

        value : Vector
            The vector value of this point's velocity in the frame
        frame : ReferenceFrame
            The frame in which this point's velocity is defined

        Examples
        ========

        >>> from sympy.physics.mechanics import Point, ReferenceFrame
        >>> N = ReferenceFrame('N')
        >>> p1 = Point('p1')
        >>> p1.set_vel(N, 10 * N.x)
        >>> p1.vel(N)
        10*N.x

        """

        value = _check_vector(value)
        _check_frame(frame)
        self._vel_dict.update({frame: value})
Exemplo n.º 3
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    def locatenew(self, name, value):
        """Creates a new point with a position defined from this point.

        Parameters
        ==========

        name : str
            The name for the new point
        value : Vector
            The position of the new point relative to this point

        Examples
        ========

        >>> from sympy.physics.mechanics import ReferenceFrame, Point
        >>> N = ReferenceFrame('N')
        >>> P1 = Point('P1')
        >>> P2 = P1.locatenew('P2', 10 * N.x)

        """

        if not isinstance(name, str):
            raise TypeError('Must supply a valid name')
        value = _check_vector(value)
        p = Point(name)
        p.set_pos(self, value)
        self.set_pos(p, -value)
        return p
Exemplo n.º 4
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    def set_acc(self, frame, value):
        """Used to set the acceleration of this Point in a ReferenceFrame.

        Parameters
        ==========

        value : Vector
            The vector value of this point's acceleration in the frame
        frame : ReferenceFrame
            The frame in which this point's acceleration is defined

        Examples
        ========

        >>> from sympy.physics.mechanics import Point, ReferenceFrame
        >>> N = ReferenceFrame('N')
        >>> p1 = Point('p1')
        >>> p1.set_acc(N, 10 * N.x)
        >>> p1.acc(N)
        10*N.x

        """

        value = _check_vector(value)
        _check_frame(frame)
        self._acc_dict.update({frame: value})
Exemplo n.º 5
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    def set_pos(self, otherpoint, value):
        """Used to set the position of this point w.r.t. another point.

        Parameters
        ==========

        value : Vector
            The vector which defines the location of this point
        point : Point
            The other point which this point's location is defined relative to

        Examples
        ========

        >>> from sympy.physics.mechanics import Point, ReferenceFrame
        >>> N = ReferenceFrame('N')
        >>> p1 = Point('p1')
        >>> p2 = Point('p2')
        >>> p1.set_pos(p2, 10 * N.x)
        >>> p1.pos_from(p2)
        10*N.x

        """

        value = _check_vector(value)
        self._check_point(otherpoint)
        self._pos_dict.update({otherpoint: value})
        otherpoint._pos_dict.update({self: -value})
Exemplo n.º 6
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    def set_vel(self, frame, value):
        """Sets the velocity Vector of this Point in a ReferenceFrame.

        Parameters
        ==========

        value : Vector
            The vector value of this point's velocity in the frame
        frame : ReferenceFrame
            The frame in which this point's velocity is defined

        Examples
        ========

        >>> from sympy.physics.mechanics import Point, ReferenceFrame
        >>> N = ReferenceFrame('N')
        >>> p1 = Point('p1')
        >>> p1.set_vel(N, 10 * N.x)
        >>> p1.vel(N)
        10*N.x

        """

        value = _check_vector(value)
        _check_frame(frame)
        self._vel_dict.update({frame: value})
Exemplo n.º 7
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    def set_acc(self, frame, value):
        """Used to set the acceleration of this Point in a ReferenceFrame.

        Parameters
        ==========

        value : Vector
            The vector value of this point's acceleration in the frame
        frame : ReferenceFrame
            The frame in which this point's acceleration is defined

        Examples
        ========

        >>> from sympy.physics.mechanics import Point, ReferenceFrame
        >>> N = ReferenceFrame('N')
        >>> p1 = Point('p1')
        >>> p1.set_acc(N, 10 * N.x)
        >>> p1.acc(N)
        10*N.x

        """

        value = _check_vector(value)
        _check_frame(frame)
        self._acc_dict.update({frame: value})
Exemplo n.º 8
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    def locatenew(self, name, value):
        """Creates a new point with a position defined from this point.

        Parameters
        ==========

        name : str
            The name for the new point
        value : Vector
            The position of the new point relative to this point

        Examples
        ========

        >>> from sympy.physics.mechanics import ReferenceFrame, Point
        >>> N = ReferenceFrame('N')
        >>> P1 = Point('P1')
        >>> P2 = P1.locatenew('P2', 10 * N.x)

        """

        if not isinstance(name, str):
            raise TypeError('Must supply a valid name')
        value = _check_vector(value)
        p = Point(name)
        p.set_pos(self, value)
        self.set_pos(p, -value)
        return p
Exemplo n.º 9
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def get_motion_params(frame, **kwargs):
    """
    Returns the three motion parameters - (acceleration, velocity, and
    position) as vectorial functions of time in the given frame.

    If a higher order differential function is provided, the lower order
    functions are used as boundary conditions. For example, given the
    acceleration, the velocity and position parameters are taken as
    boundary conditions.

    The values of time at which the boundary conditions are specified
    are taken from timevalue1(for position boundary condition) and
    timevalue2(for velocity boundary condition).

    If any of the boundary conditions are not provided, they are taken
    to be zero by default (zero vectors, in case of vectorial inputs). If
    the boundary conditions are also functions of time, they are converted
    to constants by substituting the time values in the dynamicsymbols._t
    time Symbol.

    This function can also be used for calculating rotational motion
    parameters. Have a look at the Parameters and Examples for more clarity.

    Parameters
    ==========

    frame : ReferenceFrame
        The frame to express the motion parameters in

    acceleration : Vector
        Acceleration of the object/frame as a function of time

    velocity : Vector
        Velocity as function of time or as boundary condition
        of velocity at time = timevalue1

    position : Vector
        Velocity as function of time or as boundary condition
        of velocity at time = timevalue1

    timevalue1 : sympyfiable
        Value of time for position boundary condition

    timevalue2 : sympyfiable
        Value of time for velocity boundary condition

    Examples
    ========

    >>> from sympy.physics.mechanics import ReferenceFrame, get_motion_params, dynamicsymbols
    >>> from sympy import symbols
    >>> R = ReferenceFrame('R')
    >>> v1, v2, v3 = dynamicsymbols('v1 v2 v3')
    >>> v = v1*R.x + v2*R.y + v3*R.z
    >>> get_motion_params(R, position = v)
    (v1''*R.x + v2''*R.y + v3''*R.z, v1'*R.x + v2'*R.y + v3'*R.z, v1*R.x + v2*R.y + v3*R.z)
    >>> a, b, c = symbols('a b c')
    >>> v = a*R.x + b*R.y + c*R.z
    >>> get_motion_params(R, velocity = v)
    (0, a*R.x + b*R.y + c*R.z, a*t*R.x + b*t*R.y + c*t*R.z)
    >>> parameters = get_motion_params(R, acceleration = v)
    >>> parameters[1]
    a*t*R.x + b*t*R.y + c*t*R.z
    >>> parameters[2]
    a*t**2/2*R.x + b*t**2/2*R.y + c*t**2/2*R.z

    """

    ##Helper functions

    def _process_vector_differential(vectdiff, condition, \
                                     variable, ordinate, frame):
        """
        Helper function for get_motion methods. Finds derivative of vectdiff wrt
        variable, and its integral using the specified boundary condition at
        value of variable = ordinate.
        Returns a tuple of - (derivative, function and integral) wrt vectdiff

        """

        #Make sure boundary condition is independent of 'variable'
        if condition != 0:
            condition = frame.express(condition)
        #Special case of vectdiff == 0
        if vectdiff == Vector(0):
            return (0, 0, condition)
        #Express vectdiff completely in condition's frame to give vectdiff1
        vectdiff1 = frame.express(vectdiff)
        #Find derivative of vectdiff
        vectdiff2 = frame.dt(vectdiff)
        #Integrate and use boundary condition
        vectdiff0 = Vector(0)
        lims = (variable, ordinate, variable)
        for dim in frame:
            function1 = vectdiff1.dot(dim)
            abscissa = dim.dot(condition).subs({variable: ordinate})
            # Indefinite integral of 'function1' wrt 'variable', using
            # the given initial condition (ordinate, abscissa).
            vectdiff0 += (integrate(function1, lims) + abscissa) * dim
        #Return tuple
        return (vectdiff2, vectdiff, vectdiff0)

    ##Function body

    _check_frame(frame)
    #Decide mode of operation based on user's input
    if 'acceleration' in kwargs:
        mode = 2
    elif 'velocity' in kwargs:
        mode = 1
    else:
        mode = 0
    #All the possible parameters in kwargs
    #Not all are required for every case
    #If not specified, set to default values(may or may not be used in
    #calculations)
    conditions = [
        'acceleration', 'velocity', 'position', 'timevalue', 'timevalue1',
        'timevalue2'
    ]
    for i, x in enumerate(conditions):
        if x not in kwargs:
            if i < 3:
                kwargs[x] = Vector(0)
            else:
                kwargs[x] = S(0)
        elif i < 3:
            _check_vector(kwargs[x])
        else:
            kwargs[x] = sympify(kwargs[x])
    if mode == 2:
        vel = _process_vector_differential(kwargs['acceleration'],
                                           kwargs['velocity'],
                                           dynamicsymbols._t,
                                           kwargs['timevalue2'], frame)[2]
        pos = _process_vector_differential(vel, kwargs['position'],
                                           dynamicsymbols._t,
                                           kwargs['timevalue1'], frame)[2]
        return (kwargs['acceleration'], vel, pos)
    elif mode == 1:
        return _process_vector_differential(kwargs['velocity'],
                                            kwargs['position'],
                                            dynamicsymbols._t,
                                            kwargs['timevalue1'], frame)
    else:
        vel = frame.dt(kwargs['position'])
        acc = frame.dt(vel)
        return (acc, vel, kwargs['position'])
Exemplo n.º 10
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 def _set_gravity_vector(self, vec):
     _check_vector(vec)
     self._gravity_vector = vec
     self._gravity_vector_updated.fire()
Exemplo n.º 11
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def get_motion_params(frame, **kwargs):
    """
    Returns the three motion parameters - (acceleration, velocity, and
    position) as vectorial functions of time in the given frame.

    If a higher order differential function is provided, the lower order
    functions are used as boundary conditions. For example, given the
    acceleration, the velocity and position parameters are taken as
    boundary conditions.

    The values of time at which the boundary conditions are specified
    are taken from timevalue1(for position boundary condition) and
    timevalue2(for velocity boundary condition).

    If any of the boundary conditions are not provided, they are taken
    to be zero by default (zero vectors, in case of vectorial inputs). If
    the boundary conditions are also functions of time, they are converted
    to constants by substituting the time values in the dynamicsymbols._t
    time Symbol.

    This function can also be used for calculating rotational motion
    parameters. Have a look at the Parameters and Examples for more clarity.

    Parameters
    ==========

    frame : ReferenceFrame
        The frame to express the motion parameters in

    acceleration : Vector
        Acceleration of the object/frame as a function of time

    velocity : Vector
        Velocity as function of time or as boundary condition
        of velocity at time = timevalue1

    position : Vector
        Velocity as function of time or as boundary condition
        of velocity at time = timevalue1

    timevalue1 : sympyfiable
        Value of time for position boundary condition

    timevalue2 : sympyfiable
        Value of time for velocity boundary condition

    Examples
    ========

    >>> from sympy.physics.mechanics import ReferenceFrame, get_motion_params, dynamicsymbols
    >>> from sympy import symbols
    >>> R = ReferenceFrame('R')
    >>> v1, v2, v3 = dynamicsymbols('v1 v2 v3')
    >>> v = v1*R.x + v2*R.y + v3*R.z
    >>> get_motion_params(R, position = v)
    (v1''*R.x + v2''*R.y + v3''*R.z, v1'*R.x + v2'*R.y + v3'*R.z, v1*R.x + v2*R.y + v3*R.z)
    >>> a, b, c = symbols('a b c')
    >>> v = a*R.x + b*R.y + c*R.z
    >>> get_motion_params(R, velocity = v)
    (0, a*R.x + b*R.y + c*R.z, a*t*R.x + b*t*R.y + c*t*R.z)
    >>> parameters = get_motion_params(R, acceleration = v)
    >>> parameters[1]
    a*t*R.x + b*t*R.y + c*t*R.z
    >>> parameters[2]
    a*t**2/2*R.x + b*t**2/2*R.y + c*t**2/2*R.z

    """

    ##Helper functions

    def _process_vector_differential(vectdiff, condition, \
                                     variable, ordinate, frame):
        """
        Helper function for get_motion methods. Finds derivative of vectdiff wrt
        variable, and its integral using the specified boundary condition at
        value of variable = ordinate.
        Returns a tuple of - (derivative, function and integral) wrt vectdiff

        """

        #Make sure boundary condition is independent of 'variable'
        if condition != 0:
            condition = frame.express(condition)
        #Special case of vectdiff == 0
        if vectdiff == Vector(0):
            return (0, 0, condition)
        #Express vectdiff completely in condition's frame to give vectdiff1
        vectdiff1 = frame.express(vectdiff)
        #Find derivative of vectdiff
        vectdiff2 = frame.dt(vectdiff)
        #Integrate and use boundary condition
        vectdiff0 = Vector(0)
        lims = (variable, ordinate, variable)
        for dim in frame:
            function1 = vectdiff1.dot(dim)
            abscissa = dim.dot(condition).subs({variable:ordinate})
            # Indefinite integral of 'function1' wrt 'variable', using
            # the given initial condition (ordinate, abscissa).
            vectdiff0 += (integrate(function1, lims) + abscissa)*dim
        #Return tuple
        return (vectdiff2, vectdiff, vectdiff0)

    ##Function body

    _check_frame(frame)
    #Decide mode of operation based on user's input
    if 'acceleration' in kwargs:
        mode = 2
    elif 'velocity' in kwargs:
        mode = 1
    else:
        mode = 0
    #All the possible parameters in kwargs
    #Not all are required for every case
    #If not specified, set to default values(may or may not be used in
    #calculations)
    conditions = ['acceleration', 'velocity', 'position',
                  'timevalue', 'timevalue1', 'timevalue2']
    for i, x in enumerate(conditions):
        if x not in kwargs:
            if i < 3:
                kwargs[x] = Vector(0)
            else:
                kwargs[x] = S(0)
        elif i < 3:
            _check_vector(kwargs[x])
        else:
            kwargs[x] = sympify(kwargs[x])
    if mode == 2:
        vel = _process_vector_differential(kwargs['acceleration'],
                                           kwargs['velocity'],
                                           dynamicsymbols._t,
                                           kwargs['timevalue2'], frame)[2]
        pos = _process_vector_differential(vel, kwargs['position'],
                                           dynamicsymbols._t,
                                           kwargs['timevalue1'], frame)[2]
        return (kwargs['acceleration'], vel, pos)
    elif mode == 1:
        return _process_vector_differential(kwargs['velocity'],
                                            kwargs['position'],
                                            dynamicsymbols._t,
                                            kwargs['timevalue1'], frame)
    else:
        vel = frame.dt(kwargs['position'])
        acc = frame.dt(vel)
        return (acc, vel, kwargs['position'])
Exemplo n.º 12
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 def _set_gravity_vector(self, vec):
     _check_vector(vec)
     self._gravity_vector = vec
     self._gravity_vector_updated.fire()