Week 3

Lecture Notes

Ben-Ari Ch's 1 and 2
- Ben-Ari slides: PDF
- Formula (number of possible interleavings):
  - # interleavings = $\Large \frac{(nk)!} {(k!)^n}$
  - where n = # processes and k = # steps / process
  - assumes all n processes have same number of steps (k)

Homework

Written HW: Ben-Ari p. 39:
- Exercises 2, 3, and 4
- Due: Thu, Feb 5
- Note: this is not a programming assignment, and not Programming Assignment 2, which is found below.
- Please hand in a paper copy — in class or in the bin outside my office door

UPC

Unified Parallel C
see resources in sidebar
tutorial introduction

ssh keys

you need to set up your accounts for ssh'ing between workstations without password prompts
if you already have your ssh-keys set up, skip the next step!
follow these steps to establish a trust connection for your account among our workstations
1. $ ssh-keygen
  hit enter through all the prompts
2. $ cd ~/.ssh
3. then type this command:
```
$ cat id_rsa.pub >> authorized_keys
```
for more information about ssh and public key authentication, see: Secure_Shell

workstations in:
- Asprey Lab: al101 – al120
  - note: the workstations in Asprey also have alias names after famous people in computing
- SP 309: sp309-171 – sp309-197
ssh into other workstations to test your ssh keys
- first time you ssh to workstation you will be prompted to confirm it's okay: yes
- subsequent logins to that workstation should be without passwords or prompts!
- this is what you need to do before attempting to run your UPC programs

setup

create a bin directory if you don't already have one:
- $ cd
- $ mkdir bin
copy my UPC setup script into your bin directory:
- $ cp ~mlsmith/bin/set-upc-env ~/bin
run your setup script:
- $ source ~/bin/set-upc-env

copy the tutorial programs to your account under your course directory:
- $ cd ~/cs377
- $ cp -r ~mlsmith/cs377-examples/upc ./
  this will create a upc directory under your course directory
now you're ready to compile and run! (see sidebar technical reference)

Programming Assignment 2

UPC Exercises 1.1 through 1.7
Due: Thu, Feb 12
Important notes:
- see individual workstation assignments on the Assignments page
- update your UPC_NODES in the set-upc-env script to not include your assigned workstation.

Hints

For timing your C/UPC programs, add the following to your code

      #include <time.h>
 
      int main()
      {
        clock_t startTime = clock();
        // your code to compute the C->F temperature conversions here
        // .
        // .
        clock_t endTime = clock();
        double cpuTime = ((double) (endTime - startTime)) / CLOCKS_PER_SEC;
        // print cpu time used
        // .
        // .
      }

Here's another reference:
https://sourceware.org/glibc/manual/latest/html_node/CPU-Time.html