Added James' wrist control loop code.
diff --git a/frc971/control_loops/python/control_loop.py b/frc971/control_loops/python/control_loop.py
new file mode 100644
index 0000000..47550a1
--- /dev/null
+++ b/frc971/control_loops/python/control_loop.py
@@ -0,0 +1,219 @@
+import controls
+import numpy
+
+class ControlLoop(object):
+  def __init__(self, name):
+    """Constructs a control loop object.
+
+    Args:
+      name: string, The name of the loop to use when writing the C++ files.
+    """
+    self._name = name
+
+    self._namespace_start = ("namespace frc971 {\n"
+                             "namespace control_loops {\n\n")
+
+    self._namespace_end = ("}  // namespace frc971\n"
+                           "}  // namespace control_loops\n")
+
+    self._header_start = ("#ifndef FRC971_CONTROL_LOOPS_%s_MOTOR_PLANT_H_\n"
+                          "#define FRC971_CONTROL_LOOPS_%s_MOTOR_PLANT_H_\n\n"
+                          % (self._name.upper(), self._name.upper()))
+
+    self._header_end = ("#endif  // FRC971_CONTROL_LOOPS_%s_MOTOR_PLANT_H_\n"
+                        % (self._name.upper()))
+
+  def ContinuousToDiscrete(self, A_continuous, B_continuous, dt, C):
+    """Calculates the discrete time values for A and B as well as initializing
+      X and Y to the correct sizes.
+
+      Args:
+        A_continuous: numpy.matrix, The continuous time A matrix
+        B_continuous: numpy.matrix, The continuous time B matrix
+        dt: float, The time step of the control loop
+        C: C
+    """
+    self.A, self.B = controls.c2d(
+        A_continuous, B_continuous, dt)
+    self.X = numpy.zeros((self.A.shape[0], 1))
+    self.Y = C * self.X
+    self.X_hat = numpy.zeros((self.A.shape[0], 1))
+
+  def PlaceControllerPoles(self, poles):
+    """Places the controller poles.
+
+    Args:
+      poles: array, An array of poles.  Must be complex conjegates if they have
+        any imaginary portions.
+    """
+    self.K = controls.dplace(self.A, self.B, poles)
+
+  def PlaceObserverPoles(self, poles):
+    """Places the observer poles.
+
+    Args:
+      poles: array, An array of poles.  Must be complex conjegates if they have
+        any imaginary portions.
+    """
+    self.L = controls.dplace(self.A.T, self.C.T, poles).T
+
+  def Update(self, U):
+    """Simulates one time step with the provided U."""
+    U = numpy.clip(U, self.U_min, self.U_max)
+    self.X = self.A * self.X + self.B * U
+    self.Y = self.C * self.X + self.D * U
+
+  def UpdateObserver(self, U):
+    """Updates the observer given the provided U."""
+    self.X_hat = (self.A * self.X_hat + self.B * U +
+                  self.L * (self.Y - self.C * self.X_hat - self.D * U))
+
+  def _DumpMatrix(self, matrix_name, matrix):
+    """Dumps the provided matrix into a variable called matrix_name.
+
+    Args:
+      matrix_name: string, The variable name to save the matrix to.
+      matrix: The matrix to dump.
+
+    Returns:
+      string, The C++ commands required to populate a variable named matrix_name
+        with the contents of matrix.
+    """
+    ans = ["  Eigen::Matrix<double, %d, %d> %s;\n" % (
+        matrix.shape[0], matrix.shape[1], matrix_name)]
+    first = True
+    for element in numpy.nditer(matrix, order='C'):
+      if first:
+        ans.append("  %s << " % matrix_name)
+        first = False
+      else:
+        ans.append(", ")
+      ans.append(str(element))
+
+    ans.append(";\n")
+    return "".join(ans)
+
+  def _DumpPlantHeader(self, plant_name):
+    """Writes out a c++ header declaration which will create a Plant object.
+
+    Args:
+      plant_name: string, the name of the plant.  Used to create the name of the
+        function.  The function name will be Make<plant_name>Plant().
+
+    Returns:
+      string, The header declaration for the function.
+    """
+    num_states = self.A.shape[0]
+    num_inputs = self.B.shape[1]
+    num_outputs = self.C.shape[0]
+    return "StateFeedbackPlant<%d, %d, %d> Make%sPlant();\n" % (
+        num_states, num_inputs, num_outputs, plant_name)
+
+  def _DumpPlant(self, plant_name):
+    """Writes out a c++ function which will create a Plant object.
+
+    Args:
+      plant_name: string, the name of the plant.  Used to create the name of the
+        function.  The function name will be Make<plant_name>Plant().
+
+    Returns:
+      string, The function which will create the object.
+    """
+    num_states = self.A.shape[0]
+    num_inputs = self.B.shape[1]
+    num_outputs = self.C.shape[0]
+    ans = ["StateFeedbackPlant<%d, %d, %d> Make%sPlant() {\n" % (
+        num_states, num_inputs, num_outputs, plant_name)]
+
+    ans.append(self._DumpMatrix("A", self.A))
+    ans.append(self._DumpMatrix("B", self.B))
+    ans.append(self._DumpMatrix("C", self.C))
+    ans.append(self._DumpMatrix("D", self.D))
+    ans.append(self._DumpMatrix("U_max", self.U_max))
+    ans.append(self._DumpMatrix("U_min", self.U_min))
+
+    ans.append("  return StateFeedbackPlant<%d, %d, %d>"
+               "(A, B, C, D, U_max, U_min);\n" % (num_states, num_inputs,
+                                                  num_outputs))
+    ans.append("}\n")
+    return "".join(ans)
+
+  def _DumpLoopHeader(self, loop_name):
+    """Writes out a c++ header declaration which will create a Loop object.
+
+    Args:
+      loop_name: string, the name of the loop.  Used to create the name of the
+        function.  The function name will be Make<loop_name>Loop().
+
+    Returns:
+      string, The header declaration for the function.
+    """
+    num_states = self.A.shape[0]
+    num_inputs = self.B.shape[1]
+    num_outputs = self.C.shape[0]
+    return "StateFeedbackLoop<%d, %d, %d> Make%sLoop();\n" % (
+        num_states, num_inputs, num_outputs, loop_name)
+
+  def _DumpLoop(self, loop_name):
+    """Returns a c++ function which will create a Loop object.
+
+    Args:
+      loop_name: string, the name of the loop.  Used to create the name of the
+        function and create the plant.  The function name will be
+        Make<loop_name>Loop().
+
+    Returns:
+      string, The function which will create the object.
+    """
+    num_states = self.A.shape[0]
+    num_inputs = self.B.shape[1]
+    num_outputs = self.C.shape[0]
+    ans = ["StateFeedbackLoop<%d, %d, %d> Make%sLoop() {\n" % (
+        num_states, num_inputs, num_outputs, loop_name)]
+
+    ans.append(self._DumpMatrix("L", self.L))
+    ans.append(self._DumpMatrix("K", self.K))
+
+    ans.append("  return StateFeedbackLoop<%d, %d, %d>"
+               "(L, K, Make%sPlant());\n" % (num_states, num_inputs,
+                                             num_outputs, loop_name))
+    ans.append("}\n")
+    return "".join(ans)
+
+  def DumpHeaderFile(self, file_name):
+    """Writes the header file for creating a Plant and Loop object.
+
+    Args:
+      file_name: string, name of the file to write the header file to.
+    """
+    with open(file_name, "w") as fd:
+      fd.write(self._header_start)
+      fd.write("#include \"frc971/control_loops/state_feedback_loop.h\"\n")
+      fd.write('\n')
+      fd.write(self._namespace_start)
+      fd.write(self._DumpPlantHeader(self._name))
+      fd.write('\n')
+      fd.write(self._DumpLoopHeader("Wrist"))
+      fd.write('\n')
+      fd.write(self._namespace_end)
+      fd.write('\n')
+      fd.write(self._header_end)
+
+  def DumpCppFile(self, file_name, header_file_name):
+    """Writes the C++ file for creating a Plant and Loop object.
+
+    Args:
+      file_name: string, name of the file to write the header file to.
+    """
+    with open(file_name, "w") as fd:
+      fd.write("#include \"frc971/control_loops/%s\"\n" % header_file_name)
+      fd.write('\n')
+      fd.write("#include \"frc971/control_loops/state_feedback_loop.h\"\n")
+      fd.write('\n')
+      fd.write(self._namespace_start)
+      fd.write('\n')
+      fd.write(self._DumpPlant(self._name))
+      fd.write('\n')
+      fd.write(self._DumpLoop(self._name))
+      fd.write('\n')
+      fd.write(self._namespace_end)