<html><body><div style="color:#000; background-color:#fff; font-family:arial, helvetica, sans-serif;font-size:12pt"><div><div>I sent this email with some pictures (that Rick requested) on Monday but it seems have been over the size limit for the list and has gone to moderation! <span style="font-size: 12pt;">Anyway, here is the text without the pictures... </span></div><div><br></div></div><div>Hi All,<br><span style="font-size: 12pt;"><br></span></div><div><span style="font-size: 12pt;">I've finally got some time to write up our results from our cluster experiments on Friday Night. We managed to get 10 raspberry Pies in the cluster.</span><br></div><div><br>The target was to beat my laptop which ran the monte carlo pi calculation method in 4 minutes 50 Seconds.<br><br>Our results are as follows</div><div style="background-color: transparent;"><br></div><div style="background-color: transparent;"></div><table cellspacing="0"
border="0" style="padding: 0px;"><colgroup width="61"></colgroup><colgroup width="85"></colgroup><colgroup width="29"></colgroup><colgroup width="59"></colgroup><colgroup width="63"></colgroup><colgroup span="3" width="85"></colgroup><tbody style="width: 554px;"><tr><td height="47" align="RIGHT" style="border-spacing: 2px;">No. of Pies</td><td align="RIGHT" style="border-spacing: 2px;">Seconds</td><td align="RIGHT" style="border-spacing: 2px;"><br></td><td align="RIGHT" style="border-spacing: 2px;">Minutes</td><td align="RIGHT" style="border-spacing: 2px;">Seconds</td><td align="RIGHT" style="border-spacing: 2px;"><br></td><td align="RIGHT" style="border-spacing: 2px;">Percentage Reduction in time taken</td><td align="RIGHT" style="border-spacing: 2px;">Average Reduction</td></tr><tr><td height="16" align="RIGHT" style="border-spacing: 2px;">1</td><td align="RIGHT" style="border-spacing: 2px;">1794.485</td><td align="LEFT" style="border-spacing:
2px;"><br></td><td align="RIGHT" style="border-spacing: 2px;">29</td><td align="RIGHT" style="border-spacing: 2px;">54</td><td align="LEFT" style="border-spacing: 2px;"><br></td><td align="LEFT" style="border-spacing: 2px;"><br></td><td align="LEFT" style="border-spacing: 2px;"><br></td></tr><tr><td height="16" align="RIGHT" style="border-spacing: 2px;">2</td><td align="RIGHT" style="border-spacing: 2px;">1288.508</td><td align="LEFT" style="border-spacing: 2px;"><br></td><td align="RIGHT" style="border-spacing: 2px;">21</td><td align="RIGHT" style="border-spacing: 2px;">29</td><td align="LEFT" style="border-spacing: 2px;"><br></td><td align="RIGHT" style="border-spacing: 2px;">28.20%</td><td align="RIGHT" style="border-spacing: 2px;">28.20%</td></tr><tr><td height="16" align="RIGHT" style="border-spacing: 2px;">3</td><td align="RIGHT" style="border-spacing: 2px;">859.134</td><td align="LEFT" style="border-spacing: 2px;"><br></td><td align="RIGHT"
style="border-spacing: 2px;">14</td><td align="RIGHT" style="border-spacing: 2px;">19</td><td align="LEFT" style="border-spacing: 2px;"><br></td><td align="RIGHT" style="border-spacing: 2px;">33.32%</td><td align="RIGHT" style="border-spacing: 2px;">30.76%</td></tr><tr><td height="16" align="RIGHT" style="border-spacing: 2px;">4</td><td align="RIGHT" style="border-spacing: 2px;">644.388</td><td align="LEFT" style="border-spacing: 2px;"><br></td><td align="RIGHT" style="border-spacing: 2px;">10</td><td align="RIGHT" style="border-spacing: 2px;">44</td><td align="LEFT" style="border-spacing: 2px;"><br></td><td align="RIGHT" style="border-spacing: 2px;">25.00%</td><td align="RIGHT" style="border-spacing: 2px;">28.84%</td></tr><tr><td height="16" align="RIGHT" style="border-spacing: 2px;">5</td><td align="RIGHT" style="border-spacing: 2px;">515.717</td><td align="LEFT" style="border-spacing: 2px;"><br></td><td align="RIGHT" style="border-spacing:
2px;">8</td><td align="RIGHT" style="border-spacing: 2px;">36</td><td align="LEFT" style="border-spacing: 2px;"><br></td><td align="RIGHT" style="border-spacing: 2px;">19.97%</td><td align="RIGHT" style="border-spacing: 2px;">26.62%</td></tr><tr><td height="16" align="RIGHT" style="border-spacing: 2px;">6</td><td align="RIGHT" style="border-spacing: 2px;">429.622</td><td align="LEFT" style="border-spacing: 2px;"><br></td><td align="RIGHT" style="border-spacing: 2px;">7</td><td align="RIGHT" style="border-spacing: 2px;">10</td><td align="LEFT" style="border-spacing: 2px;"><br></td><td align="RIGHT" style="border-spacing: 2px;">16.69%</td><td align="RIGHT" style="border-spacing: 2px;">24.64%</td></tr><tr><td height="16" align="RIGHT" style="border-spacing: 2px;">7</td><td align="RIGHT" style="border-spacing: 2px;">368.231</td><td align="LEFT" style="border-spacing: 2px;"><br></td><td align="RIGHT" style="border-spacing: 2px;">6</td><td align="RIGHT"
style="border-spacing: 2px;">8</td><td align="LEFT" style="border-spacing: 2px;"><br></td><td align="RIGHT" style="border-spacing: 2px;">14.29%</td><td align="RIGHT" style="border-spacing: 2px;">22.91%</td></tr><tr><td height="16" align="RIGHT" style="border-spacing: 2px;">8</td><td align="RIGHT" style="border-spacing: 2px;">322.395</td><td align="LEFT" style="border-spacing: 2px;"><br></td><td align="RIGHT" style="border-spacing: 2px;">5</td><td align="RIGHT" style="border-spacing: 2px;">22</td><td align="LEFT" style="border-spacing: 2px;"><br></td><td align="RIGHT" style="border-spacing: 2px;">12.45%</td><td align="RIGHT" style="border-spacing: 2px;">21.42%</td></tr><tr><td height="16" align="RIGHT" style="border-spacing: 2px;">9</td><td align="RIGHT" style="border-spacing: 2px;">286.442</td><td align="LEFT" style="border-spacing: 2px;"><br></td><td align="RIGHT" style="border-spacing: 2px;">4</td><td align="RIGHT" style="border-spacing:
2px;">46</td><td align="LEFT" style="border-spacing: 2px;"><br></td><td align="RIGHT" style="border-spacing: 2px;">11.15%</td><td align="RIGHT" style="border-spacing: 2px;">20.13%</td></tr><tr><td height="16" align="RIGHT" style="border-spacing: 2px;">10</td><td align="RIGHT" style="border-spacing: 2px;">257.776</td><td align="LEFT" style="border-spacing: 2px;"><br></td><td align="RIGHT" style="border-spacing: 2px;">4</td><td align="RIGHT" style="border-spacing: 2px;">18</td><td align="LEFT" style="border-spacing: 2px;"><br></td><td align="RIGHT" style="border-spacing: 2px;">10.01%</td><td align="RIGHT" style="border-spacing: 2px;">19.01%</td></tr></tbody></table><div style="background-color: transparent;"><br></div><div style="background-color: transparent;">As you can see we achieved our target of beating my laptop with 9 raspberry pies. I guess had the program we ran on the laptop made use of both cores the time taken may have been considerably
less.</div><div style="background-color: transparent;"><br></div><div style="background-color: transparent;">/* I've also attached three screen shots which show the program running with 4, 9 and 10 pies in the cluster. */</div><div style="background-color: transparent;"><br></div><div style="background-color: transparent;">In the discussions at the end we talked about how it would be possible to make the cluster easier to configure. Because the cluster relies on a fixed relationship between the IP Address/Hostname and the public keys to allow ssh to work seamlessly we needed to run with with static IP addresses. This meant each node had to be manually configured with a unique hostname and IP address as it was added to the cluster, this hostname/IP address combination then needed to be added to the ssh known_hosts file. It would be better if we could devise a more automated method of configuring new nodes - any suggestions are welcome.
</div><div style="background-color: transparent;"><br></div><div style="background-color: transparent;">We also discussed other applications that we could use a raspberry pi cluster for - again suggestions are welcome.</div><div style="background-color: transparent;"><br></div><div style="background-color: transparent;">Thanks again for your participation.</div><div style="background-color: transparent;"><br></div><div style="background-color: transparent;">Malcolm</div></div></body></html>