Hello everyone, I am having some troubles to use Tensorflow in ROS Kinetic. The error message is: (no error with catkin_make) process[Filter-1]: started with pid [21302] process[CallTensorflow-2]: started with pid [21303] Traceback (most recent call last): File "/usr/lib/python2.7/runpy.py", line 174, in _run_module_as_main "__main__", fname, loader, pkg_name) File "/usr/lib/python2.7/runpy.py", line 72, in _run_code exec code in run_globals File "/home/zoe/tensorflow-for-poets-2/scripts/label_image.py", line 25, in import tensorflow as tf ImportError: No module named tensorflow My python node is calling a .sh file which want to use and import tensorflow. Tensorflow is installed on my computer as we can see: Name: tensorflow Version: 1.7.0 Summary: TensorFlow helps the tensors flow Home-page: https://www.tensorflow.org/ Author: Google Inc. Author-email: opensource@google.com License: Apache 2.0 Location: /usr/local/lib/python3.5/dist-packages Requires: wheel, numpy, astor, protobuf, tensorboard, termcolor, gast, absl-py, grpcio, six As tensorflow is installed in python 3.5 I can only import with python3 in the terminal zoe@PC-ZOE:~$ python >>> import tensorflow as tf Traceback (most recent call last): File "", line 1, in ImportError: No module named tensorflow zoe@PC-ZOE:~$ python3 >>> import tensorflow as tf What I have already try: - change the header of the python node to `#!/usr/bin/env python3` - add `source ~/tensorflow/bin/activate` at the beginning of my .sh file. - make `source ~/tensorflow/bin/activate` before roslaunch - add `python-tensorflow-pip`in the package.xml but I can't rosdep python-tensorflow-pip (as I see here https://answers.ros.org/question/228940/integrating-tensorflow-into-ros/) Can anyone help me, please? Thank you.

Hy everybody, I am currently writing a function for a ros node. During this calculation I am trying to use the pseudo inverse of the QR Module of Eigen. But unfortunately it is not able to find the include and by that not the function. I think I need to alter my Cmake file. I did already use normal functions so this is not the problem. I found a stack overflow post in which it seems very easy to use the function. Just for clarity I add the link here: [stack overflow post](https://stackoverflow.com/questions/44465197/eigen-library-pseudo-inverse-of-matrix-matlab-pinv) Thank you very much for your help. Since I am not posting very often just tell me when I need to change anything. I will add all the information as soon as possible. The code I am trying to make run: #include #include "ros/ros.h" #include #include #include #include #include //<- can't find this import void calc_delta_p(Eigen::Matrix &delta_p,Eigen::Matrix &hessian){ hessian.completeOrthogonalDecomposition().pseudoInverse(); //<-cant find this function delta_p=hessian*delta_p; } The compiler throws this error: /home/catkin_ws/src/image_publisher/src/function_file.cpp:120:13: error: ‘class Eigen::Matrix’ has no member named ‘completeOrthogonalDecomposition’ hessian.completeOrthogonalDecomposition().pseudoInverse(); Here is my cmake file: cmake_minimum_required(VERSION 2.8.3) project(image_publisher) ## Compile as C++11, supported in ROS Kinetic and newer # add_compile_options(-std=c++11) ## Find catkin macros and libraries ## if COMPONENTS list like find_package(catkin REQUIRED COMPONENTS xyz) ## is used, also find other catkin packages find_package(catkin REQUIRED COMPONENTS cv_bridge #opencv2 roscpp sensor_msgs std_msgs cmake_modules #eigen dynamic_reconfigure message_generation ) ## System dependencies are found with CMake's conventions # find_package(Boost REQUIRED COMPONENTS system) ## Generate messages in the 'msg' folder add_message_files( FILES sixDOF.msg ) ## Generate added messages and services with any dependencies listed here generate_messages( DEPENDENCIES sensor_msgs std_msgs ) ## Generate dynamic reconfigure parameters in the 'cfg' folder generate_dynamic_reconfigure_options( cfg/dynamic_reconfigure_file.cfg ) ################################### ## catkin specific configuration ## ################################### ## The catkin_package macro generates cmake config files for your package ## Declare things to be passed to dependent projects ## INCLUDE_DIRS: uncomment this if your package contains header files ## LIBRARIES: libraries you create in this project that dependent projects also need ## CATKIN_DEPENDS: catkin_packages dependent projects also need ## DEPENDS: system dependencies of this project that dependent projects also need catkin_package( INCLUDE_DIRS include # LIBRARIES image_publisher CATKIN_DEPENDS cv_bridge roscpp sensor_msgs std_msgs dynamic_reconfigure message_runtime #opencv2 # DEPENDS system_lib DEPENDS Eigen #Eigen library ) ########### ## Build ## ########### find_package(OpenCV) find_package(Eigen REQUIRED) #eigenlibrary set( PROPRIETARY_FUNCTIONS_H include/image_publisher/function_file.h ) set( PROPRIETARY_FUNCTIONS_CPP src/function_file.cpp ) ## Specify additional locations of header files ## Your package locations should be listed before other locations include_directories( include ${catkin_INCLUDE_DIRS} ${OpenCV_INCLUDE_DIRS} ${Eigen_INCLUDE_DIRS} # ${PROPRIETARY_FUNCTIONS_CPP} # ${PROPRIETARY_FUNCTIONS_H} ) ## Declare a C++ library # add_library(${PROJECT_NAME} # src/${PROJECT_NAME}/image_publisher.cpp # ) #always before add dependencies ## Declare a C++ executable ## With catkin_make all packages are built within a single CMake context ## The recommended prefix ensures that target names across packages don't collide add_executable(image_publisher_node src/image_publisher_node.cpp ${PROPRIETARY_FUNCTIONS_CPP} ${PROPRIETARY_FUNCTIONS_H} ) add_executable(image_subscriber_node src/image_subscriber_node.cpp ${PROPRIETARY_FUNCTIONS_H} ${PROPRIETARY_FUNCTIONS_CPP}) add_executable(test_node src/test_node.cpp ${PROPRIETARY_FUNCTIONS_H} ${PROPRIETARY_FUNCTIONS_CPP}) ## Add cmake target dependencies of the library ## as an example, code may need to be generated before libraries ## either from message generation or dynamic reconfigure add_dependencies(image_publisher_node ${catkin_EXPORTED_TARGETS} ${${PROJECT_NAME}_EXPORTED_TARGETS}) add_dependencies(image_subscriber_node ${catkin_EXPORTED_TARGETS} ${${PROJECT_NAME}_EXPORTED_TARGETS}) add_dependencies(test_node ${catkin_EXPORTED_TARGETS} ${${PROJECT_NAME}_EXPORTED_TARGETS}) add_dependencies(image_publisher_node ${PROJECT_NAME}_gencfg) ## Add cmake target dependencies of the executable ## same as for the library above # add_dependencies(${PROJECT_NAME}_node ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS}) ## Specify libraries to link a library or executable target against target_link_libraries(image_publisher_node ${catkin_LIBRARIES} ${OpenCV_LIBRARIES}) target_link_libraries(image_subscriber_node ${catkin_LIBRARIES} ${OpenCV_LIBRARIES}) target_link_libraries(test_node ${catkin_LIBRARIES} ${OpenCV_LIBRARIES})

Hi I'm trying to create a hand model in Rviz but when I'm trying to launch my hand model, terminal shows error but my robot model has been launched without mesh error: [joint_state_publisher-1] process has died [pid 23769, exit code 1, cmd /opt/ros/kinetic/lib/joint_state_publisher/joint_state_publisher __name:=joint_state_publisher __log:=/home/misiek/.ros/log/f283dd5c-6a41-11e8-bf9c-000c2952c6a7/joint_state_publisher-1.log]. log file: /home/misiek/.ros/log/f283dd5c-6a41-11e8-bf9c-000c2952c6a7/joint_state_publisher-1*.log my urdf code: 1000.010.010.010.0Gazebo/Grey1000.010.010.010.0Gazebo/Grey1000.010.010.010.0Gazebo/Grey1000.010.010.010.0Gazebo/Grey1000.010.010.010.0Gazebo/Grey1000.010.010.010.0Gazebo/Grey1000.010.010.010.0Gazebo/Grey1000.010.010.010.0Gazebo/Grey Launch file: Thank you in advance

Hi, I have installed opencv 3.4.2 from source with CUDA support in my tX2 and i also i have installed ros which include opencv 3.3.1dev I have managed to use the correct opencv version when i use ros with cpp using the CMakeLists but when i try to use opencv in python, the opencv used is the one from ros which i dont want import cv2 as cv print cv.__version__ 3.3.1dev I would like to be able to use the opencv which is in the repository: usr/local/lib/python2.7/dist-packages I guess python will look directly in the folder of ros which contains the lib (opt/ros/kinetic/lib/python/cv2.so) but i would like to avoid this and link directly to the global one Moreover after symlink the opencv from source to my virtual env, it seems that even the virtual env use the opencv from ros. Does someone have an idea how to do this? Thank you

I`m trying to write a ros module in python, but I'm facing this issue below: import: not authorized `rospy' @ error/constitute.c/WriteImage/1028. from: can't read /var/mail/sensor_msgs.msg from: can't read /var/mail/tf2_msgs.msg from: can't read /var/mail/geometry_msgs.msg from: can't read /var/mail/cv_bridge Is there any configuration wrong in CmkaList.txt or package.xml? Am I missing any file for cmake compile correctly python code? EDIT #1: Added code #!/usr/bin/env python import rospy from sensor_msgs.msg import Image,CameraInfo from tf2_msgs.msg import TFMessage from geometry_msgs.msg import TransformStamped from cv_bridge import CvBridge import airsim import cv2 import numpy as np here

0 The question is all about importing a module called leap_interface.py to send.py and using a of the functions defined in leap_interface. I ask this question, because the leap_interface module is a bit complicated. It contains multi classes. First, I defined function get_extended_fingers(self) in class LeapInterface in leap_interface module as below: class LeapInterface(Leap.Listener): def on_init(self, controller): ... def on_disconnect(self, controller): ... def on_exit(self, controller): print "Exited Leap Motion Controller" def on_frame(self, controller): # Get the most recent frame and report some basic information frame = controller.frame() # Number of extended fingers Steven def get_extended_fingers(self): #print "extendedfingers: %d" % len(extended_finger_list) return len(extended_finger_list) Secondly, I want to use this function as an if condition in the file sender.py: if li.get_extended_fingers < 2: msg.direction.x = hand_direction_[0]# - initial_pose[0] msg.direction.y = hand_direction_[1] msg.direction.z = hand_direction_[2] print "works1" if li.get_extended_fingers > 4: msg.ypr.x = hand_yaw_ msg.ypr.y = hand_pitch_ msg.ypr.z = hand_roll_ print "works2" However, my solution doesn't work properly. It my terminal, it keeps printing works2, no matter how many extended fingers I show in the field of view of my leap motion sensor. Can you please tell me what I did wrong? leap_interface.py import sys import time import threading import Leap from Leap import CircleGesture, KeyTapGesture, ScreenTapGesture, SwipeGesture class LeapFinger(): def __init__(self, finger=None): self.boneNames = ['metacarpal', 'proximal', 'intermediate', 'distal'] for boneName in self.boneNames: setattr(self, boneName, [0.0, 0.0, 0.0]) self.tip = [0.0, 0.0, 0.0] self.leapBoneNames = [Leap.Bone.TYPE_METACARPAL, Leap.Bone.TYPE_PROXIMAL, Leap.Bone.TYPE_INTERMEDIATE, Leap.Bone.TYPE_DISTAL] if finger is not None: self.importFinger(finger) def importFinger(self, finger): for boneName in self.boneNames: # Get the base of each bone bone = finger.bone(getattr(Leap.Bone, 'TYPE_%s' % boneName.upper())) setattr(self, boneName, bone.prev_joint.to_float_array()) # For the tip, get the end of the distal bone self.tip = finger.bone(Leap.Bone.TYPE_DISTAL).next_joint.to_float_array() class LeapInterface(Leap.Listener): def on_init(self, controller): # These variables as probably not thread safe # TODO: Make thread safe ;) self.hand = [0,0,0] self.right_hand = False self.left_hand = False self.hand_direction = [0,0,0] self.hand_normal = [0,0,0] self.hand_palm_pos = [0,0,0] # Velocity Steven self.hand_palm_vel = [0,0,0] # Finger tip velocity Steven self.index_tip_vel = [0,0,0] self.hand_pitch = 0.0 self.hand_yaw = 0.0 self.hand_roll = 0.0 self.fingerNames = ['thumb', 'index', 'middle', 'ring', 'pinky'] for fingerName in self.fingerNames: setattr(self, fingerName, LeapFinger()) print "Initialized Leap Motion Device" def on_connect(self, controller): print "Connected to Leap Motion Controller" # Enable gestures controller.enable_gesture(Leap.Gesture.TYPE_CIRCLE); controller.enable_gesture(Leap.Gesture.TYPE_KEY_TAP); controller.enable_gesture(Leap.Gesture.TYPE_SCREEN_TAP); controller.enable_gesture(Leap.Gesture.TYPE_SWIPE); def on_disconnect(self, controller): # Note: not dispatched when running in a debugger. print "Disconnected Leap Motion" def on_exit(self, controller): print "Exited Leap Motion Controller" def on_frame(self, controller): # Get the most recent frame and report some basic information frame = controller.frame() '''print "Frame id: %d, timestamp: %d, hands: %d, fingers: %d, tools: %d, gestures: %d" % ( frame.id, frame.timestamp, len(frame.hands), len(frame.fingers), len(frame.tools), len(frame.gestures()))''' if not frame.hands.is_empty: #recently changed in API # Get the first hand #we are seeking one left and one right hands there_is_right_hand=False there_is_left_hand=False for hand in frame.hands: if hand.is_right: there_is_right_hand=True self.right_hand=hand elif hand.is_left: there_is_left_hand=True self.left_hand=hand if not there_is_right_hand: self.right_hand=False if not there_is_left_hand: self.left_hand=False self.hand = frame.hands[0] #old way # Check if the hand has any fingers fingers = self.hand.fingers extended_finger_list = fingers.extended() #print type(extended_finger_list) print "extendedfingers: %d" % len(extended_finger_list) if not fingers.is_empty: for fingerName in self.fingerNames: #finger = fingers.finger_type(Leap.Finger.TYPE_THUMB)[0] #self.thumb.importFinger(finger) # finger_type(type)Returns a FingerList object containing only the specified finger types, i.e. only thumbs, or only index fingers, etc. Steven finger = fingers.finger_type(getattr(Leap.Finger, 'TYPE_%s' % fingerName.upper()))[0] getattr(self, fingerName).importFinger(finger) # Get the hand's sphere radius and palm position # print "Hand sphere radius: %f mm, palm position: %s" % (self.hand.sphere_radius, hand.palm_position) # Get the hand's normal vector and direction normal = self.hand.palm_normal direction = self.hand.direction pos = self.hand.palm_position # How about the velocity of hand Steven vel = self.hand.palm_velocity #Pointable represents fingers here pointable = self.hand.pointables[0] tip_vel = pointable.tip_velocity self.hand_direction[0] = direction.x self.hand_direction[1] = direction.y self.hand_direction[2] = direction.z self.hand_normal[0] = normal.x self.hand_normal[1] = normal.y self.hand_normal[2] = normal.z self.hand_palm_pos[0] = pos.x self.hand_palm_pos[1] = pos.y self.hand_palm_pos[2] = pos.z self.hand_pitch = direction.pitch * Leap.RAD_TO_DEG self.hand_yaw = normal.yaw * Leap.RAD_TO_DEG self.hand_roll = direction.roll * Leap.RAD_TO_DEG # Velocity Steven self.hand_palm_vel[0] = vel.x self.hand_palm_vel[1] = vel.y self.hand_palm_vel[2] = vel.z # Pointables Steven self.index_tip_vel[0] = tip_vel.x self.index_tip_vel[1] = tip_vel.y self.index_tip_vel[2] = tip_vel.z # use the following if condition to clear the data after moveing hand out of the FOV Steven if frame.hands.is_empty: self.hand_direction[0] = 0 self.hand_direction[1] = 0 self.hand_direction[2] = 0 self.hand_normal[0] = 0 self.hand_normal[1] = 0 self.hand_normal[2] = 0 self.hand_palm_pos[0] = 0 self.hand_palm_pos[1] = 0 self.hand_palm_pos[2] = 0 self.hand_pitch = 0 self.hand_yaw = 0 self.hand_roll = 0 # Velocity self.hand_palm_vel[0] = 0 self.hand_palm_vel[1] = 0 self.hand_palm_vel[2] = 0 # Pointables Steven self.index_tip_vel[0] = 0 self.index_tip_vel[1] = 0 self.index_tip_vel[2] = 0 def get_hand_direction(self): return self.hand_direction def get_hand_normal(self): return self.hand_normal def get_hand_palmpos(self): return self.hand_palm_pos def get_hand_yaw(self): return self.hand_yaw def get_hand_pitch(self): return self.hand_pitch def get_hand_roll(self): return self.hand_roll def get_finger_point(self, fingerName, fingerPointName): return getattr(getattr(self, fingerName), fingerPointName) # Velocity Steven def get_hand_palmvel(self): return self.hand_palm_vel # Finger tip velocity Steven def get_index_tipvel(self): return self.index_tip_vel # Number of extended fingers Steven def get_extended_fingers(self): #print "extendedfingers: %d" % len(extended_finger_list) return len(extended_finger_list) class Runner(threading.Thread): def __init__(self,arg=None): threading.Thread.__init__(self) self.arg=arg self.listener = LeapInterface() self.controller = Leap.Controller() self.controller.add_listener(self.listener) def __del__(self): self.controller.remove_listener(self.listener) def get_hand_direction(self): return self.listener.get_hand_direction() def get_hand_normal(self): return self.listener.get_hand_normal() def get_hand_palmpos(self): return self.listener.get_hand_palmpos() def get_hand_roll(self): return self.listener.get_hand_roll() def get_hand_pitch(self): return self.listener.get_hand_pitch() def get_hand_yaw(self): return self.listener.get_hand_yaw() def get_finger_point(self, fingerName, fingerPointName): return self.listener.get_finger_point(fingerName, fingerPointName) # Velocity def get_hand_palmvel(self): return self.listener.get_hand_palmvel() # Finger tip velocity Steven def get_index_tipvel(self): return self.listener.get_index_tipvel() # Number of extended fingers Steven def get_extended_fingers(self): return len(extended_finger_list) #print "extendedfingers: %d" % len(extended_finger_list) #return self.listener.get_extended_fingers() def run (self): while True: # Save some CPU time time.sleep(0.001) sender.py #!/usr/bin/env python import argparse import rospy import leap_interface from leap_motion.msg import leap from leap_motion.msg import leapros '''FREQUENCY_ROSTOPIC_DEFAULT = 0.01(original rate)''' FREQUENCY_ROSTOPIC_DEFAULT = 1 NODENAME = 'leap_pub' PARAMNAME_FREQ = 'freq' PARAMNAME_FREQ_ENTIRE = '/' + NODENAME + '/' + PARAMNAME_FREQ def sender(): ''' This method publishes the data defined in leapros.msg to /leapmotion/data ''' rospy.loginfo("Parameter set on server: PARAMNAME_FREQ= {}".format(rospy.get_param(PARAMNAME_FREQ_ENTIRE, FREQUENCY_ROSTOPIC_DEFAULT))) li = leap_interface.Runner() li.setDaemon(True) li.start() # pub = rospy.Publisher('leapmotion/raw',leap) pub_ros = rospy.Publisher('leapmotion/data',leapros, queue_size=2) rospy.init_node(NODENAME) while not rospy.is_shutdown(): hand_direction_ = li.get_hand_direction() hand_normal_ = li.get_hand_normal() hand_palm_pos_ = li.get_hand_palmpos() hand_pitch_ = li.get_hand_pitch() hand_roll_ = li.get_hand_roll() hand_yaw_ = li.get_hand_yaw() # Velocity Steven hand_palm_vel_ = li.get_hand_palmvel() index_tip_vel_ = li.get_index_tipvel() msg = leapros() #frame.hands[0].fingers.extended() #print "extendedfingers: %d" % li.get_extended_fingers() if li.get_extended_fingers < 2: msg.direction.x = hand_direction_[0]# - initial_pose[0] msg.direction.y = hand_direction_[1] msg.direction.z = hand_direction_[2] msg.normal.x = hand_normal_[0] msg.normal.y = hand_normal_[1] msg.normal.z = hand_normal_[2] msg.palmpos.x = hand_palm_pos_[0] msg.palmpos.y = hand_palm_pos_[1] msg.palmpos.z = hand_palm_pos_[2] # Velocity Steven msg.palmvel.x = hand_palm_vel_[0] msg.palmvel.y = hand_palm_vel_[1] msg.palmvel.z = hand_palm_vel_[2] # Pointable/Finger tip velocity Steven msg.tipvel.x = index_tip_vel_[0] msg.tipvel.y = index_tip_vel_[1] msg.tipvel.z = index_tip_vel_[2] print "works1" #fingerNames = ['thumb', 'index', 'middle', 'ring', 'pinky'] #fingerPointNames = ['metacarpal', 'proximal', #'intermediate', 'distal', 'tip'] #for fingerName in fingerNames: #for fingerPointName in fingerPointNames: #pos = li.get_finger_point(fingerName, fingerPointName) #for iDim, dimName in enumerate(['x', 'y', 'z']): #setattr(getattr(msg, '%s_%s' % (fingerName, fingerPointName)), #dimName, pos[iDim]) '''if frame.hands.is_empty: msg.index_tip.x = 0 msg.index_tip.y = 0 msg.index_tip.z = 0''' if li.get_extended_fingers > 4: msg.ypr.x = hand_yaw_ msg.ypr.y = hand_pitch_ msg.ypr.z = hand_roll_ print "works2" # We don't publish native data types, see ROS best practices # pub.publish(hand_direction=hand_direction_,hand_normal = hand_normal_, hand_palm_pos = hand_palm_pos_, hand_pitch = hand_pitch_, hand_roll = hand_roll_, hand_yaw = hand_yaw_) pub_ros.publish(msg) rospy.sleep(rospy.get_param(PARAMNAME_FREQ_ENTIRE, FREQUENCY_ROSTOPIC_DEFAULT)) if __name__ == '__main__': try: sender() except rospy.ROSInterruptException: pass

Hello, I started having a look at Ros 2 (crystal) two weeks ago and really had a hard time creating a package that produces some executables. As I managed to do that I tried to migrate some old code to Ros 2 code. It was just a tiny project which moved a frame in a circel around the world-frame's center in rviz. To do that I used the TransformBroadcaster imported from tf. I saw that there is now tf2 in my rosdistro/share, so I tried to import that with `import tf2`, but this threw a ModuleNotFoundError: No module named 'tf2' The weird thing is, I can import TFMessage from tf2_msgs and publish TFMessages to tf 'by hand'. This really feels like I overlooked something trivial but as I didn't find anything so far I wanted to ask here.

Hello, I'm having trouble importing my package into Eclipse. It worked before, but since a few days it causes trouble. When I open resp. try to import my project the following error message is displayed: Description Resource Path Location Type Error 127 occurred while running autoreconf follow_me -1 Configure Problem I removed my previous version of Eclipse and installed the newest version: Eclipse IDE for C/C++ Version: 2019-03 (4.11.0). Previously I used Eclipse 2018-09 (4.9.0). According to [this tutorial on the wiki page](http://wiki.ros.org/action/fullsearch/IDEs?action=fullsearch&context=180&value=linkto%3A%22IDEs%22#Creating_the_Eclipse_project_files) I performed the following steps to import the project: 1. In folder catkin_ws: `catkin_make --force-cmake -G"Eclipse CDT4 - Unix Makefiles"` 2. `awk -f $(rospack find mk)/eclipse.awk build/.project > build/.project_with_env && mv build/.project_with_env build/.project` 3. Started Eclipse in a new terminal by: `bash -i -c ~/Software/Eclipse/eclipse/eclipse` (Note: I sourced ~/catkin_ws/devel/setup.bash in ~/.bashrc ) 4. In Eclipse: *File > Import... > General > Existing Projects into Workspace > Next > As root directory: /home/username/catkin_ws/src/follow_me > No other option selected > Finish* The Console output tells: CDT Build Console [follow_me] Build stopped () And the aforementioned error is shown under the "Problems" tab. Also the "src" folder is grayed out as well as the containing source files. I've already tried to reimport my package. Also I can't finish step 4 when I create a new empty package in catkin_ws. I'm using **ROS Kinetic under Ubuntu 16.04 (64 bit) with kernel version 4.15.0-47-generic**. What can I do to properly import and use my package in Eclipse? Thanks in advance for any help!

Hello, I'm trying to do a simple suscriber on rosout but I can't get it to work (I'm a begineer). I'm working on a computer from work. When I type "rosgraph_msgs.msg import Clock", python says "can't open file 'rosgraph_msgs' : [Errno 2] No such file or directory". I'm on Ubuntu 14.04.6 Lts. I'm using ROSindigo. I can't understand why I can't import a basic dependancy when Ros itself is working very fine (I can, for instance, display the data of the topic rosout when it's running). "from std_msgs.msg import String" works too. Just not "from rosgraph_msgs.msg import Clock". I don't understand why. If you have any ideas, Kind Regards,