How do I determine the cartesian coordinates of the end effector if I know the joint angles?

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I have the SRDF file which gives the joint angles of the robot for the different poses (using Moveit). Now in order to do a pick and place task, I need to give the cartesian coordinates of the object in the frame of the robot. So, I moved my robot using Moveit to a position such that the end effector can grasp the object, so that I have the joint angles of the robot for performing the grasp. But, I need the position of the end effector with respect to the robot, when the robot is in that position. How do I determine that?