More Quiz Questions Parallel Programming MPI Collective routines ITCS 4/5145 Parallel Programming, UNC-Charlotte, B. Wilkinson QuizQuestions2b.ppt February 5, 2016

What is the name of the MPI routine that combines a gather operation with an arithmetic or logical operation called? Select one: a. MPI_Scatter() b. MPI_Combine() c. MPI_Reduce() d. MPI_Gather_Op() e. MPI_Gather()

Most collective MPI operations (broadcast, gather, scatter, etc Most collective MPI operations (broadcast, gather, scatter, etc. ...) have a parameter called root. What does this parameter define? Select one: a. The name of the root user b. The process that acts as the source of the original data if this data is sent to other processors or the destination if data is collected to one point. c. The process that acts as the destination of data. d. The name of the user. e. The process that acts as the source of data.

MPI collective routines do not use message tags MPI collective routines do not use message tags.  Suggest a plausible reason behind this from those reasons given below (not in the slides). Select one: a. MPI collective routines do use tags.  This is a flawed question. b. All the processes must call the routine with the same or compatible parameters, and at a specific place in the program. c. The MPI designers were lazy d. Tags would be impossible to implement e. Programs generally only call one collective routine.

The MPI collective routines are said to have the same semantics as using point-point MPI_send() and MPI_recv() routines separately in respect to when they return. If so, when does the MPI_Bcast() routine return? They all return when the message has been received by all processes. The root returns when its local actions are complete but the message may have not been received and each destination process returns when it receives the message. The root returns when its local actions are complete but the message may have not been received and all destination processes return when all have received the message. Never Immediately even before local actions arte complete. None or the other answers.