Ariel's profile - activity

Publishing directly is reduces a bit the frequency but not that much. The processor is running at 666MHz, so copying a 6

Slow publisher with callback Hi, I am publishing images with the usb_cam package on a PC and subscribing to them with a

Hi,

I have a simple publisher which I want to launch with different parameters (rate and length) using the same code:

#include "ros/ros.h"
#include "std_msgs/String.h"

int main(int argc, char **argv)
{
    std::string NODE_NAME = "pc_pub_string";
    ros::init(argc, argv, NODE_NAME);
    ros::NodeHandle n;

    ros::Publisher string_pub = n.advertise<std_msgs::String>(NODE_NAME, 100);

    // Get the sample rate of this node (set in the launch file)
    ros::NodeHandle np("~");
    int loop_rate_p, data_length_p;
    if(np.getParam("loop_rate", loop_rate_p)){
        ROS_INFO("Initialized [%s] node at %d Hz", NODE_NAME.c_str(), loop_rate_p);
    }
    else{
        ROS_ERROR("Couldn't get rate parameter");
        return 0;
    }
    if(np.getParam("data_length", data_length_p)){
        ROS_INFO("Initialized [%s] node with %d elements in data", NODE_NAME.c_str(), data_length_p);
    }
    else{
        ROS_ERROR("Couldn't get data length parameter");
        return 0;
    }
    ros::Rate loop_rate(loop_rate_p);

    // Populate string message (content doesn't matter for proof of concept)
    std_msgs::String str;
    for(int i=0; i<data_length_p; i++)
        str.data.push_back(i);

    while(ros::ok())
    {
        string_pub.publish(str);
        ros::spinOnce();
        loop_rate.sleep();
    }


    return 0;
}

For this, I am using this launch file:

<launch>

  <group ns="publisher">
    <node pkg="proof_of_concept_string_ips" name="pc_pub_string0" type="pc_pub_string">
      <param name="loop_rate" type="int" value="2" />
      <param name="data_length" type="int" value="4" />
      <remap from="publisher/pc_pub_string" to="publisher/pc_pub_string0"/>
    </node>

    <node pkg="proof_of_concept_string_ips" name="pc_pub_string1" type="pc_pub_string">
      <param name="loop_rate" type="int" value="4" />
      <param name="data_length" type="int" value="2" />
      <remap from="publisher/pc_pub_string" to="publisher/pc_pub_string1"/>
    </node>    

  </group>

</launch>

The issue is that in the topic list, I only see what I wrote in NODE_NAME = "pc_pub_string". However, with ros info I can see that there are two publisher. I was hoping to have two topics, one called pc_pub_string0 and another pc_pub_string1. This could be achieved by having 2 .cpp files and compile 2 different executables, but their code would be the same.

Is it possible to avoid having two executables and use only one to manipulate their parameters (also topic names to have multiple) from the launch file?

Thanks for the help.

The error is in the launch file. The remap should not include the group name: <remap from="pc_pub_string" to="pc_pub_

Launch same node multiple times Hi, I have a simple publisher which I want to launch with different parameters (rate an

Launch same node multiple times Hi, I have a simple publisher which I want to launch with different parameters (rate an

launch same node multiple times Hi, I have a simple publisher which I want to launch with different parameters (rate an

launch same node multiple times Hi, I have a simple publisher which I want to launch with different parameters (rate an

Launch same node multiple times Hi, I have a simple publisher which I want to launch with different parameters (rate an

According to the documentation (as suggested by @gvdhoorn) the code should look something like this: #include "ros/ros.

Removing the commented things during tested I deleted the ros::spinOnce(); (edited). The code now implements a solution

True, it is not fully working like posted there, but seems to be the way to go with respect to the queues. I believe the

According to the documentation (as suggested by @gvdhoorn) the code should look something like this: #include "ros/ros.

According to the documentation (as suggested by @gvdhoorn) the code should look something like this: int main(int argc,

True, it is not fully working like posted there, but seems to be the way to go with respect to the queues. I believe the

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Those are quite interesting points. You are right, there is no need to reserialize to increase the overhead. However, th

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it seems this is the way to go. Unfortunately I haven't found any example that shows how to check which queue for the me

it seems this is the way to go. Unfortunately I haven't found any example that shows how to check which queue for the me

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