Add a function to convert a string to a tuple

    * src/dynamic_graph/signal_base.py: string format should be
    '[n](x_1,...,x_{n-1}'.

src/dynamic_graph/signal_base.py

@@ -4,6 +4,28 @@
   Author: Florent Lamiraux
 """
 import wrap
+import re
+
+def stringToTuple(vector):
+    """
+    Transform a string of format '[n](x_1, x_2, ..., x_{n-1} into a list of
+    numbers
+    """
+    # Find vector length
+    a = re.search('[\d]', vector)
+    size = int(a.group(0))
+    format = '\('
+    for i in range(size):
+        format += '(.*)'
+        if i != size-1:
+            format += ','
+    format += '\)'
+    a = re.search(format, vector)
+    res = []
+    for i in range(1, size+1):
+        res.append(float(a.group(i)))
+    return tuple(res)
+
 
 class SignalBase (object) :
     """