<div dir="ltr">I think my first guess attempt was off, for a 8x8 projection I got<div><br></div><div>proj2['x']/pf.units['cm']*8 = proj2['px']<br></div><div><br></div><div style>so I think the px is center x coordinate of each pixel in the projection.</div>
<div style><br></div><div style>From</div><div style>G.S.</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Mon, Aug 19, 2013 at 11:30 PM, Geoffrey So <span dir="ltr"><<a href="mailto:gsiisg@gmail.com" target="_blank">gsiisg@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div>Hi, I just tried your script on a small enzo dataset of 64 cube in size</div><div class="im"><div><br>
</div>"<div class="gmail_default" style="font-size:13px;font-family:tahoma,sans-serif;display:inline">
1. What exactly is returned in proj2? Why does it span from 0. to 1. when I specified source=cube?"<br></div></div><div class="gmail_default" style="font-size:13px;font-family:tahoma,sans-serif;display:inline"><br>- proj2['Density'] got values of a 2D matrix showing the results of the unweighted projection of 'Density' along z in the x,y plane, in my case the projection was 2x2 pixels. I think the reason it span from 0 to 1 is because you ran a simulation with normalized code units the left edge being 0 and right edge being 1.<div class="im">
<br>
<br>"2. I also tried 'data_source=cube' instead of 'source=cube'. It did not raise any error, and returned<br></div></div><div class="im"><div class="gmail_default" style="font-size:13px;font-family:tahoma,sans-serif;display:inline">
something different: array of same shape, but with different data values.<br>Is this keyword also used</div><div class="gmail_default" style="font-size:13px;font-family:tahoma,sans-serif;display:inline"> for projection object? Is there a consistent difference between the two keywords in yt?"<br>
</div></div><div class="gmail_default" style="font-size:13px;font-family:tahoma,sans-serif;display:inline"><br>- I tried <div>>pf.h.proj(2, 'Density', center=center, data_source=cube)<br></div><div>and got:</div>
<div>KeyError: 'No field named px'<br></div><div><br></div><div>I'm not familiar with the different versions of yt so if you can reply with the results of</div><div>>yt instinfo</div>
<div>I'm sure someone more knowledgable can pinpoint the version you're using and come up with why there's a discrepancy (I'm using an slightly outdated developer's version). I could be wrong so someone please correct me, but if I recall correctly I think the data_source newer form for specifying the input in the newer ProjectionPlot API.</div>
<div class="im">
<br>"3. I could not find documentation on some fields like 'px', 'py' that seem to be generated for certain data containers<br>(e.g., 't' for ray objects). Is there an exhaustive list of such fields in the documentation?"</div>
</div>
<div><div class="gmail_default" style="font-size:13px;font-family:tahoma,sans-serif;display:inline"><br></div></div><div><div class="gmail_default" style="font-size:13px;font-family:tahoma,sans-serif;display:inline">- You might have gotten different px, py because you were able to do a different data_source, if you left it with source=cube, what I got in return for >proj2['px'] and >proj2['py'], were</div>
<span style="font-family:tahoma,sans-serif;font-size:13px"> the x y edges </span><span style="font-family:tahoma,sans-serif;font-size:13px">of cells that are in the projection proj2 in the normalized code units.</span></div>
<div><span style="font-family:tahoma,sans-serif;font-size:13px"><br></span></div><div><span style="font-family:tahoma,sans-serif;font-size:13px">- doing a</span></div><div><span style="font-family:tahoma,sans-serif;font-size:13px">></span>help(proj2)</div>
<div>revealed that proj2 is an 'AMRProj' object, putting it into the search in the documentation revealed the API page for that base object at the following link</div><div><a href="http://yt-project.org/doc/api/generated/yt.data_objects.data_containers.AMRProjBase.html?highlight=amrproj" target="_blank">http://yt-project.org/doc/api/generated/yt.data_objects.data_containers.AMRProjBase.html?highlight=amrproj</a><br>
</div><div>from there I only see 'source' as a kwarg and not data_source, so that's probably why I'm getting an error when I tried it.</div><div><br></div><div>- doing a</div><div>>proj2.fields</div>
<div>lists the different fields, some like x, dx are in cgs, and px and pdx are in your simulation code units, in this case normalized to 1. I believe the x, dx are the cell-center, and cell-center-distance. I'm not sure about px, pdx, but looking at the values (I changed halfwidth=0.05 to have a bigger than 2x2 projection to play with), I'm going to guess px is the distance of each cell to the center of the projection parallel to x, and pdx is the x-spacing between each cell center.</div>
<div><br></div><div>Hope this helps.</div><div><br></div><div>From</div><div>G.S.</div><div><br></div><div>PS. The documentation is being actively improved upon by the developers, so I believe feedback are always welcomed.</div>
<div><br></div></div><div class="gmail_extra"><br><br><div class="gmail_quote"><div><div class="h5">On Mon, Aug 19, 2013 at 9:22 PM, Semyeong Oh <span dir="ltr"><<a href="mailto:semyeongoh@gmail.com" target="_blank">semyeongoh@gmail.com</a>></span> wrote:<br>
</div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div class="h5"><div dir="ltr"><div class="gmail_default" style="font-family:tahoma,sans-serif"><span style="font-family:courier new,monospace">Hi all,<br>
<br>I'm new to yt. I have questions about making projections of certain region, and inspecting the data returned.<br>
<br>I made a cube as follows:<br>
<br><div class="gmail_default" style="font-family:tahoma,sans-serif;display:inline">import pylab as pl</div><br>center = [0.5, 0.5, 0.5]<br>halfwidth = 0.005<br>cube = pf.h.region(center, center-pl.ones(3)*halfwidth, center+pl.ones(3)*halfwidth, ['Density'])<br>
<br>print min(cube['x']), max(cube['x'])<br>0.494873046875 0.505126953125<br><br>When I print cube['x'].shape, I get (10728,).<br>I tried to make a projection of this cube along z-axis as follows:<br>
<br>proj2 = pf.h.proj(2, 'Density', center=center, source=cube)<br><br>But I could not understand what is returned.<br><br>print min(proj2['p</span><div class="gmail_default" style="display:inline"><span style="font-family:courier new,monospace"></span></div>
<span style="font-family:courier new,monospace">x']), max(proj2['py']), proj2['px'].shape<br>0.00390625 0.99609375 (19648,)<br><br>print proj2['Density']<br>[ 0. 0. 0. ..., 0. 0. 0.]<br><br>
<div class="gmail_default" style="font-family:tahoma,sans-serif;display:inline">My questions are:<br></div><div class="gmail_default" style="font-family:tahoma,sans-serif;display:inline">1. What exactly is returned in proj2? Why does it span from 0. to 1. when I specified source=cube?<br>
</div><div class="gmail_default" style="font-family:tahoma,sans-serif;display:inline"><br>2. I also tried 'data_source=cube' instead of 'source=cube'. It did not raise any error, and returned<br></div><div class="gmail_default" style="font-family:tahoma,sans-serif;display:inline">
something different: array of same shape, but with different data values.<br>Is this keyword also used</div><div class="gmail_default" style="font-family:tahoma,sans-serif;display:inline"> for projection object? Is there a consistent difference between the two keywords in yt?<br>
</div><div class="gmail_default" style="font-family:tahoma,sans-serif;display:inline"><br>3. I could not find documentation on some fields like 'px', 'py' that seem to be generated for certain data containers<br>
(e.g., 't' for ray objects). Is there an exhaustive list of such fields in the documentation?<br><br></div><div class="gmail_default" style="font-family:tahoma,sans-serif;display:inline">Thanks in advance.<span><font color="#888888"><br>
<br>
</font></span></div><span><font color="#888888"><div class="gmail_default" style="font-family:tahoma,sans-serif;display:inline">Semyeong<br></div></font></span></span></div></div>
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