signal_base.py

"""
  Copyright (C) 2010 CNRS

  Author: Florent Lamiraux
"""
import wrap
import entity
import re

def stringToTuple (vector) :
    """
    Transform a string of format '[n](x_1,x_2,...,x_n)' into a tuple of numbers.
    """
    # Find vector length
    a = re.match('\[(\d+)\]',vector)
    size = int(a.group(1))
    # remove '[n]' prefix
    vector = vector[len(a.group(0)):]
    # remove '(' and ')' at beginning and end
    vector = vector.lstrip('(').rstrip(')\n')
    # split string by ','
    vector = vector.split(',')
    # check size
    if len(vector) != size:
        raise TypeError('displayed size ' +
                        size + ' of vector does not fit actual size: '
                        + str(len(vector)))
    res = map(float, vector)
    return tuple (res)

def tupleToString (vector) :
    """
    Transform a tuple of numbers into a string of format
    '[n](x_1, x_2, ..., x_n)'
    """
    string = '[%d]('%len (vector)
    for x in vector[:-1]:
        string += '%f,'%x
    string += '%f)'%vector[-1]
    return string

def stringToMatrix (string) :
    """
    Transform a string of format
    '[n,m]((x_11,x_12,...,x_1m),...,(x_n1,x_n2,...,x_nm))' into a tuple
    of tuple of numbers.
    """
    # Find matrix size
    a = re.search ('\[(\d+),(\d+)]', string)
    nRows = int (a.group(1))
    nCols = int (a.group(2))
    # Remove '[n,m]' prefix
    string = string[len(a.group(0)):]
    rows = string.split('),(')
    if len(rows) != nRows:
        raise TypeError('displayed nb rows ' +
                        nRows + ' of matrix does not fit actual nb rows: '
                        + str(len(rows)))
    m = []
    for rstr in rows:
        rstr = rstr.lstrip('(').rstrip(')\n')
        r = map(float, rstr.split(','))
        if len(r) != nCols:
            raise TypeError('one row length ' +
                            len(r) +
                            ' of matrix does not fit displayed nb cols: ' +
                            nCols)
        m.append(tuple(r))
    return tuple (m)

def matrixToString(matrix) :
    """
    Transform a tuple of tuple of numbers into a string of format
    '[n,m]((x_11,x_12,...,x_1m),...,(x_n1,x_n2,...,x_nm))'.
    """
    nRows = len(matrix)
    if nRows is 0 :
        return '[0,0](())'
    nCols = len(matrix[0])
    string = '[%d,%d](' % (nRows, nCols)
    for r in range (nRows) :
        string += '('
        for c in range (nCols) :
            string += str (float (matrix [r][c]))
            if c != nCols-1 :
                string += ','
        string += ')'
        if r != nRows -1 :
            string += ','
    string += ')'
    return string

def objectToString(obj) :
    """
    Transform an object to a string. Object is either
      - an entity (more precisely a sub-class named Feature)
      - a matrix
      - a vector or
      - a floating point number,
      - an integer,
      - a boolean,
    """
    if (isinstance(obj, tuple)) :
        # matrix or vector
        if len(obj) is 0 :
            return ""
        else :
            if (isinstance(obj[0], tuple)) :
                #matrix
                return matrixToString(obj)
            else :
                #vector
                return tupleToString(obj)
    elif isinstance(obj, entity.Entity) :
        return obj.name
    else :
        return str(obj)

def stringToObject(string) :
    """
    Convert a string into one of the following types
      - a matrix (tuple of tuple),
      - a vector,
      - an integer,
      - a floating point number.
    Successively attempts conversion in the above order and return
    on success. If no conversion fits, the string is returned.
    """
    try :
        return stringToMatrix(string)
    except :
        pass
    try :
        return stringToTuple(string)
    except :
        pass
    try :
        return int(string)
    except :
        pass
    try :
        return float(string)
    except :
        return string

class SignalBase (object) :
    """
    This class binds dynamicgraph::SignalBase<int> C++ class
    """

    obj = None

    def __init__(self, name = "", obj = None) :
        """
        Constructor: if not called by a child class, create and store a pointer
        to a C++ SignalBase<int> object.
        """
        if obj :
            self.obj = obj
        if not self.obj :
            self.obj = wrap.create_signal_base(self, name)

    @property
    def time(self) :
        """
        Get time of signal
        """
        return wrap.signal_base_get_time(self.obj)

    @property
    def value(self) :
        """
        Setter and getter for the value of a signal

        Binds C++ SignalBase<int>::get() and set() methods. Values are passed
        through string streams.
        A string is interpreted as respectively:
            * a matrix (tuple of tuple) if string fits '[n,m]((x_11,x_12,...,x_1m),...,(x_n1,x_n2,...,x_nm))' format where n and m are integers, x_ij are floating point numbers,
            * a tuple if string fits '[n](x_1, x_2, ..., x_n)' format,
            * an integer,
            * a floating point number.

        If string fits none of the above formats, no conversion is performed.

        For instance, is s binds a signal of type vector,
            >>> s.value = (2.5, .1, 1e2)
        will call SignalBase<int>::set("[3](2.5,0.1,100.0)") and
            >>> s.value
            (2.5, 0.1, 100.0)
        """
        string = wrap.signal_base_get_value(self.obj)
        return stringToObject(string)

    @value.setter
    def value(self, val) :
        """
        Set the signal as a constant signal with given value.
        If the signal is plugged, it will be unplugged
        """
        string = objectToString(val)
        return wrap.signal_base_set_value(self.obj, string)

    def getName(self):
        """
        Get name of signal
        """
        return wrap.signal_base_get_name(self.obj)

    def recompute(self, time):
        """
        Force signal to recompute the value at given time.
        """
        return wrap.signal_base_recompute(self.obj, time)
    def unplug(self):
        """
        Unplug a PTR signal.
        """
        return wrap.signal_base_unplug(self.obj)

    def __str__(self):
        """
        Print signal in a string
        """
        return wrap.signal_base_display(self.obj)
    def displayDependencies(self,iter):
        """
        Print signal dependencies in a string
        """
        return(wrap.signal_base_display_dependencies(self.obj,iter))

    # Script short-cuts: don't use this syntaxt in python coding,
    # use it for debuging online only!
    @property
    def m(self):
        """
        m stands for matlab: display the content of the
        signal with matlab style, for debuging and transfert.
        matlab-style to be coded ...
        """
        print(self.value)