Dear all, <br><br><span id="result_box" class="long_text" lang="en"><span class="hps">I need</span> <span class="hps">to</span> <span class="hps">understand</span> <span class="hps">us</span> <span class="hps">better</span>, <span class="hps">define some</span> <span class="hps">terms.</span> <span class="hps">From what I've</span> <span class="hps">talked to</span> <span class="hps">Layla</span><span class="">, Emine</span> <span class="hps">and Marco</span><span>,</span> <span class="hps">the first thing you</span> <span class="hps">need to</span> <span class="hps">assemble</span> <span class="hps">a</span> <span class="hps">large</span> <span class="hps">dataset.<br>

<br>A <b>data set (or dataset)</b> is a <b>collection of data</b>, usually presented in tabular form. Each column represents a particular variable. Each row corresponds to a given member of the data set in question. Nontabular data sets can take the form of marked up strings of characters, such as an XML file.<br>

<br></span></span><span id="result_box" class="long_text" lang="en"><span class="hps">And while it</span> <span class="hps">is</span> <span class="hps">incorrect to refer</span> <span class="hps">to the</span> <span class="hps">dataset</span> <span class="hps">as a</span> <b><span class="hps">database</span></b><span>, I prefer</span> <span class="hps">to</span> <span class="hps">understand</span> <span class="hps">better</span> <span class="hps">to restrict this</span> <span class="hps">word to refer</span> <span class="hps">to the</span> <b><span class="hps">data structure</span></b><span>, rather than all</span> <span class="hps">of</span> <span class="hps">the data itself</span><span>.</span> <span class="hps">The design</span><span class="">, construction</span><span>,</span> <span class="hps">and</span> <span class="hps">maintenance</span> <span class="hps">of a</span> <span class="hps">complex</span> <span class="hps">database</span> <span class="hps">requires</span> <span class="hps">specialist</span> <span class="hps">skills.</span><br>

<br> <span class="hps">So the first thing</span> <span class="hps">is to<b> build</b></span><b> <span class="hps">the</span> <span class="hps">dataset</span></b> <span class="hps">or rather</span> <span class="hps">decide</span> <span class="hps">which</span> <span class="hps">variables</span> <span class="hps">are</span> <span class="hps">in each column</span><span>, then with</span> <span class="hps">that information and</span> <span class="hps">more specific</span> <span class="hps">requirements</span> <span class="hps">relating to</span> <span class="hps">searches</span> <span class="hps">in the</span> <span class="hps">dataset</span><span>, I can</span> <span class="hps">d<b>esign the structure of</b></span><b> <span class="hps">the</span> <span class="hps">relational database</span></b><span>.</span> <span class="hps">Another step</span> <span class="hps">is to <b>build the</b></span><b> </b><span class="hps"><b>database</b>.</span> <span class="hps">And another</span> <span class="hps">step could</span> <span class="hps">be to <b>build</b></span><b> </b><span class="hps"><b>an interface</b> for</span> <span class="hps">anyone can</span> <span class="hps">query the</span> <span class="hps">database.</span><br>

<br> <span class="hps"></span></span><span id="result_box" class="long_text" lang="en"><span class="hps">As</span> <span class="hps">I understood</span></span><span id="result_box" class="long_text" lang="en"><span class="hps"></span><span class="hps"> this</span> <span class="hps">first meeting</span> <span class="hps">to decide which</span> <span class="hps">variables or</span> <span class="hps">columns is needed</span> <span class="hps">in the dataset.</span> <span class="hps">For that</span><span>, it helps</span> <span class="hps">you</span> <span class="hps">have a clear idea</span> <span class="hps">of what you need to</span> <span class="hps">compare, or</span> <span class="hps">what the problem is</span> <span class="hps">you plan to</span> <span class="hps">solve</span> <span class="hps">once you</span> <span class="hps">have</span> <span class="hps">ordering information</span><span>.</span></span> <span id="result_box" class="long_text" lang="en"><span class="hps">In other</span> <span class="hps">words, what</span> <span class="hps">information</span> <span class="hps">you will need</span> <span class="hps">to extract from the</span> <span class="hps">dataset</span> <span class="hps alt-edited">that it is too</span> <span class="hps alt-edited">hard</span> <span class="hps">to find now?</span></span><br>

<br>Best Regards,<br><br><br><div class="gmail_quote">On Wed, Feb 8, 2012 at 10:03 AM, Layla Martin-Samos <span dir="ltr"><<a href="mailto:lmartinsamos@gmail.com">lmartinsamos@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">

Dear all, we have started an ambicious project that consist in the building of a huge data base of all-electron calculations on model systems. The data base will also include in the future pseudopotential calculations. Marco Monni is performing the all-electron calclations and Erica Vidal is in charge for constructing the informatic framework. After many discussions, we have a first embrionary idea of what should be included in the data base. We would like to organize an informal meeting for deciding a first draft of the data-base structure. How many of you are interested in participating? could you give your disponibilities for the month? Once I know the participants and approx. disponibilities I will open a doodle pool. For people abroad we can arrange skype calls or video conf.<br>


<br>thank you for your collaboration<br><br>best regards<span class="HOEnZb"><font color="#888888"><br><br>Layla<br></font></span><br>PS Emine and Oliviero can you update your contact info in the q-e-developers mailing list?<br>


</blockquote></div><br><br clear="all"><br>-- <br>Erica Vidal<br>