Dear Stefano,<br><br><span id="result_box" class="" lang="en"><span class="hps">I'm not saying</span> <span class="hps">you do not</span> <span class="hps">need</span> <span class="hps">a database</span><span>,</span> <span class="hps">I'm saying is</span> <span class="hps">that in order to</span> <span class="hps">design it</span> <span class="hps">properly</span><span>, you must first</span> <span class="hps">make it clear</span> <span class="hps">which</span> <span class="hps">data</span> <span class="hps">must be stored</span> <span class="hps">and how</span> <span class="hps">it</span> <span class="hps">intends to use</span> <span class="hps">that information.</span><br>
<br> <span class="hps">For me it is</span> <span class="hps">essential that you</span> <span class="hps">begin to</span> <span class="hps">separate data and</span> <span class="hps">data structures</span><span>.</span> <span class="hps"></span></span><span id="result_box" class="" lang="en"><span class="hps">That is why I</span></span><span id="result_box" class="" lang="en"><span class="hps"></span><span class="hps"> propose</span> <span class="hps">to call them</span> <span class="hps">differently</span><span>, so you</span> <span class="hps">notice</span> <span class="hps">the difference.</span><br>
<br> <span class="hps">It is important</span> <span class="hps">not to try to</span> <span class="hps">think at the same</span> <span class="hps">time</span> <span class="hps">what information</span> <span class="hps">must be stored and</span> <span class="hps">how to store</span> <span class="hps">that information.</span> That p<span class="hps">rocesses</span> <span class="hps">are</span> <span class="hps">related but</span> <span class="hps alt-edited">that must be done</span> <span class="hps">in different</span> <span class="hps">steps</span> <span class="hps">or you run the</span> <span class="hps">risk of doing something</span> <span class="hps">that is not</span> <span class="hps">general enough</span><span>,</span> <span class="hps">or</span> <span class="hps">make many mistakes.</span><br>
<br> <span class="hps">As in any</span> <span class="hps">software project</span> (more or less) <span class="hps">first comes the</span> <span class="hps atn">what (</span><span>requirements),</span> <span class="hps">then comes the</span> <span class="hps atn">how (</span><span class="">design),</span> <span class="hps">and then</span> <span class="hps">the implenetación</span><span>, testing and validation.</span><br>
<br> <span class="hps">So in this</span> <span class="hps">first meeting</span><span>, I think you</span> <span class="hps">should discuss</span> <span class="hps">what information</span> <span class="hps">to store</span><span>, why and</span> <span class="hps">how to use it</span><span class="">.</span> <span class="hps">The design stage</span> <span class="hps">is after</span> <span class="hps">that and</span> <span class="hps alt-edited">is about</span> <span class="hps alt-edited">to choosing</span> <span class="hps">the</span> <span class="hps">appropriate</span> <span class="hps">data structure</span> <span class="hps">to the requirements</span><span>,</span> <span class="hps">which</span> <span class="hps alt-edited">I do not think</span> <span class="hps alt-edited">prudent to</span> <span class="hps">discuss it at a</span> <span class="hps">first meeting.</span></span><br>
<br><span id="result_box" class="" lang="en"><span class="hps">I'm trying to</span> <span class="hps">save</span> <span class="hps">you</span> <span class="hps">much</span> <span class="hps">time, avoiding</span> <span class="hps">to discuss</span> <span class="hps">issues</span> <span class="hps">at a time when</span> <span class="hps">you should not.</span></span><br>
<br>Best, <br><br><br>-------- Original Message --------
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<th nowrap valign="BASELINE" align="RIGHT">Subject: </th>
<td>Re: [Q-e-developers] ALL electron and PSEUDOPOTENTIAL data
base</td>
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<th nowrap valign="BASELINE" align="RIGHT">Date: </th>
<td>Wed, 08 Feb 2012 12:37:21 +0100</td>
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<th nowrap valign="BASELINE" align="RIGHT">From: </th>
<td>Stefano de Gironcoli <a href="mailto:degironc@sissa.it" target="_blank"><degironc@sissa.it></a></td>
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<th nowrap valign="BASELINE" align="RIGHT">To: </th>
<td>Erica Maran <a href="mailto:maran@sissa.it" target="_blank"><maran@sissa.it></a>, Stefano Baroni
<a href="mailto:BARONI@SISSA.IT" target="_blank"><BARONI@SISSA.IT></a></td>
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<th nowrap valign="BASELINE" align="RIGHT">CC: </th>
<td><a href="mailto:q-e-developers@qe-forge.org" target="_blank">q-e-developers@qe-forge.org</a>, Layla Martin-Samos
<a href="mailto:lmartinsamos@gmail.com" target="_blank"><lmartinsamos@gmail.com></a>, Emine Kucukbenli
<a href="mailto:kucukben@sissa.it" target="_blank"><kucukben@sissa.it></a>, Oliviero Andreussi
<a href="mailto:oliviero.andreussi@epfl.ch" target="_blank"><oliviero.andreussi@epfl.ch></a>, Marco
<a href="mailto:marco.monni@dsf.unica.it" target="_blank"><marco.monni@dsf.unica.it></a></td>
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<pre>Dear Erica
I'm not sure my idea is correct but I I think that what we need is
more a database than a dataset.
what we want to collect are results of a series of calculations,
that can contain energies, pressure, atomic positions, value of specific
band in a certain point... since some substantial effort would be spent
in generating these data I would keep the full output(s) in the
database, properly organized (... this is the part I don't have any idea
on) and then the required information could be retrieved by
interrogating the system... rather than extract the information and then
throw away the outputs (... I always am afraid that one could forget
some important info that then is not anymore available)
is this compatible with your idea of a dataset ? does it make things
more complicated ?
I think we should discuss also this issue in the meeeting,
best
stefano</pre><br><br><br><br><div class="gmail_quote">On Wed, Feb 8, 2012 at 12:16 PM, Erica Vidal <span dir="ltr"><<a href="mailto:ericavidal@gmail.com">ericavidal@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, <br><br><span lang="en"><span>I need</span> <span>to</span> <span>understand</span> <span>us</span> <span>better</span>, <span>define some</span> <span>terms.</span> <span>From what I've</span> <span>talked to</span> <span>Layla</span><span>, Emine</span> <span>and Marco</span><span>,</span> <span>the first thing you</span> <span>need to</span> <span>assemble</span> <span>a</span> <span>large</span> <span>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 lang="en"><span>And while it</span> <span>is</span> <span>incorrect to refer</span> <span>to the</span> <span>dataset</span> <span>as a</span> <b><span>database</span></b><span>, I prefer</span> <span>to</span> <span>understand</span> <span>better</span> <span>to restrict this</span> <span>word to refer</span> <span>to the</span> <b><span>data structure</span></b><span>, rather than all</span> <span>of</span> <span>the data itself</span><span>.</span> <span>The design</span><span>, construction</span><span>,</span> <span>and</span> <span>maintenance</span> <span>of a</span> <span>complex</span> <span>database</span> <span>requires</span> <span>specialist</span> <span>skills.</span><br>
<br> <span>So the first thing</span> <span>is to<b> build</b></span><b> <span>the</span> <span>dataset</span></b> <span>or rather</span> <span>decide</span> <span>which</span> <span>variables</span> <span>are</span> <span>in each column</span><span>, then with</span> <span>that information and</span> <span>more specific</span> <span>requirements</span> <span>relating to</span> <span>searches</span> <span>in the</span> <span>dataset</span><span>, I can</span> <span>d<b>esign the structure of</b></span><b> <span>the</span> <span>relational database</span></b><span>.</span> <span>Another step</span> <span>is to <b>build the</b></span><b> </b><span><b>database</b>.</span> <span>And another</span> <span>step could</span> <span>be to <b>build</b></span><b> </b><span><b>an interface</b> for</span> <span>anyone can</span> <span>query the</span> <span>database.</span><br>
<br> <span></span></span><span lang="en"><span>As</span> <span>I understood</span></span><span lang="en"><span></span><span> this</span> <span>first meeting</span> <span>to decide which</span> <span>variables or</span> <span>columns is needed</span> <span>in the dataset.</span> <span>For that</span><span>, it helps</span> <span>you</span> <span>have a clear idea</span> <span>of what you need to</span> <span>compare, or</span> <span>what the problem is</span> <span>you plan to</span> <span>solve</span> <span>once you</span> <span>have</span> <span>ordering information</span><span>.</span></span> <span lang="en"><span>In other</span> <span>words, what</span> <span>information</span> <span>you will need</span> <span>to extract from the</span> <span>dataset</span> <span>that it is too</span> <span>hard</span> <span>to find now?</span></span><br>
<br>Best Regards,<div class="HOEnZb"><div class="h5"><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" target="_blank">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><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></div></div><span class="HOEnZb"><font color="#888888">-- <br>Erica Vidal<br>
</font></span></blockquote></div><br><br clear="all"><br>-- <br>Erica Vidal<br>