<div dir="ltr"><div style>Hi, I just tried your script on a small enzo dataset of 64 cube in size</div><div style><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 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.<br>
<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-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 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 style>and got:</div>
<div style>KeyError: 'No field named px'<br></div><div style><br></div><div style>I'm not familiar with the different versions of yt so if you can reply with the results of</div><div style>>yt instinfo</div>
<div style>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knowledgable can pinpoint the version you're using and come up with why there's a discrepancy (I'm using an slightly outdated developer's version).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>
<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 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 style><span style="font-family:tahoma,sans-serif;font-size:13px">- doing a</span></div><div style><span style="font-family:tahoma,sans-serif;font-size:13px">></span>help(proj2)</div>
<div style>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 style><a href="http://yt-project.org/doc/api/generated/yt.data_objects.data_containers.AMRProjBase.html?highlight=amrproj">http://yt-project.org/doc/api/generated/yt.data_objects.data_containers.AMRProjBase.html?highlight=amrproj</a><br>
</div><div style>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 style><br></div><div style>- doing a</div><div style>>proj2.fields</div>
<div style>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 style><br></div><div style>Hope this helps.</div><div style><br></div><div style>From</div><div style>G.S.</div><div style><br></div><div style>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">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>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><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 class="HOEnZb"><font color="#888888"><br>
<br>
</font></span></div><span class="HOEnZb"><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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