def compute_follow(grammar, first):
follow_list = []
follow_0 = Follow(0)
for n in grammar.get_nonterminals():
if n != grammar.get_start_symbol():
follow_0.set_value_symbol(n, [])
else:
follow_0.set_value_symbol(n, ["epsilon"])
follow_list.append(follow_0)
idx = 0
while True:
idx += 1
follow = Follow(idx)
for n in grammar.get_nonterminals():
f_list = []
for e in follow_list[idx - 1].get_values_for_symbol(n):
f_list.append(e)
for lhs, rhs in get_prod_with_n_rhs(n, grammar).items():
for p in rhs:
x = get_first(n, p, first)
for i in x:
if i == "epsilon":
for e in follow_list[idx -
1].get_values_for_symbol(lhs):
if e not in f_list:
f_list.append(e)
else:
if i not in f_list:
f_list.append(i)
follow.set_value_symbol(n, f_list)
follow_list.append(follow)
if compare_follows(follow_list[idx - 1], follow):
break
return follow_list[-1]
def get(self):
form = cgi.FieldStorage()
form_item = form['item'].value
form_user = form['user'].value
form_type = int(form['type'].value)
url = form['url'].value
f = Follow(
item=form_item,
user=form_user,
type=form_type,
)
f.put()
self.redirect(url, False, False, None, None)
def main():
min_altitude = 0.8 # mm
altitude_goal = 2.5 # mm
height_diff = 0 #mm
timeout = 300 # seconds
# pid_i = (kp, ki, kd, integrator, derivator, set_point)
pid_x = (6, 0.625, 2.5, 0, 0, 500)
pid_y = (6, 0.875, 3.75, 0, 0, 500)
pid_z = (0.1, 0, 0, 0, 0, altitude_goal)
pid_theta = (1 / 260.0, 0, 0, 0, 0, 0)
# set the bounding box
bbx = (375, 625)
bby = (375, 625)
bounding_box = True
bbx_min, bbx_max = bbx
bby_min, bby_max = bby
yaw_min = 10
yaw_max = 350
# controller update values
yaw_update = 0
x_update = 0
y_update = 0
z_update = 0
navdata = nd()
# Twist commands
qc = Twist()
follow = Follow(bbx, bby, pid_x, pid_y, pid_z, pid_theta, bounding_box)
rate = rospy.Rate(200)
while ((follow.state != 'follow')):
# print takeoff.state
rate.sleep()
while not rospy.is_shutdown():
# always update the altitude
if not (altitude_goal - 0.25 < navdata.altitude <
altitude_goal + 0.25):
# if (navdata.altitude < altitude_goal):
z_update = follow.pid_z.update(navdata.altitude)
# print("Theta %.2f" % navdata.theta)
# print("(%d, %d)" % (navdata.tag_x, navdata.tag_y))
if (altitude_goal - 0.25 < navdata.altitude):
qc.linear.z = 0.25
elif (navdata.altitude < altitude_goal + 0.25):
qc.linear.z = -0.25
else:
qc.linear.z = 0
if (navdata.tag_acquired):
# If 10 < theta < 350 then let's rotate
if ((yaw_min < navdata.theta) and (navdata.theta < yaw_max)):
# if ((yaw_min < navdata.theta < yaw_max)):
yaw_update = follow.pid_theta.update(navdata.theta - 180)
# print "%.3f" % yaw_update
else:
# print "No yaw!"
yaw_update = 0
# is_in_box(minimum, maximum, position)
if (follow.is_in_box(bbx_min, bbx_max, navdata.tag_y)
and follow.is_in_box(bby_min, bby_max, navdata.tag_x)):
# If the QC is in the bounding box then we should enter 'Hover'
# mode and just hang there
x_update = 0
y_update = 0
# # qc.angular.x = 0.0
# qc.angular.y = 0.0
# print("In the Box")
else:
# It's not in the bounding box therefore we should update the PIDs
x_update = follow.pid_x.update(navdata.tag_x)
y_update = follow.pid_y.update(navdata.tag_y)
# print("%.3f" % follow.pid_x.getError())
qc.angular.z = yaw_update
qc.linear.x = x_update
qc.linear.y = y_update
# qc.linear.z = z_update
follow.pub_ctrl.publish(qc)
rate.sleep()
