Hi All, yesterday I had a brain wave that it should be fairly simple to create a new kind of data container that is a hybrid of existing ones, where the mixing/cutting is done with boolean logic. I think I'm most of the way there. Let me give you some examples of what this means.
re1 = pf.h.region([0.5]*3, [0.4]*3, [0.6]*3) re2 = pf.h.region([0.5]*3, [0.5]*3, [0.6]*3) sp1 = pf.h.sphere([0.5]*3, 0.1) sp2 = pf.h.sphere([0.1]*3, 0.1)
This will give you the exact same region as re1:
re = pf.h.boolean([re1, "OR'", re2])
This will give you the same as re2:
re = pf.h.boolean([re1, "AND", re2])
This will give you the part of re1 that re2 does not cover, so re1 with a corner taken out:
re = pf.h.boolean([re1, "NOT", re2])
Likewise, this will give you a box with a sphere cut out of it in the middle:
re = pf.h.boolean([re1, "NOT", sp1])
This will combine the two disjoint spheres into one object:
re = pf.h.boolean([sp1, "OR", sp2])
Nested logic should work using parentheses, where items in parentheses are turned into new sub-hybrid regions before they are considered with the others at a 'higher' level. This will give you a disjoint region, with sp2 plus re2 with a corner cut out of it.
re = pf.h.boolean([sp2, "OR", "(", re1, "NOT", re2, ")"])
This is all being done with cut_masks so it should work fairly seamlessly. And so far, nearly everything seems to work. Except for some reason that I don't fully grasp right now, I'm changing the cut_masks of the starting regions, which is wrong. Here's an example of what I mean. If I make a hybrid region: In [1]: re1 = pf.h.region([0.5]*3, [0.4]*3, [0.6]*3) In [2]: re2 = pf.h.region([0.5]*3, [0.5]*3, [0.6]*3) In [3]: re = pf.h.boolean([re1, "AND", re2]) In [4]: re1['x'].shape yt : [INFO ] 2011-10-29 10:00:25,002 Getting field x from 4 Out[4]: (2197,) I'm seeing that re1 is being modified. Here's what I should see for the shape of ['x']: In [1]: re1 = pf.h.region([0.5]*3, [0.4]*3, [0.6]*3) In [2]: re1['x'].shape yt : [INFO ] 2011-10-29 10:14:04,730 Getting field x from 4 Out[2]: (17576,) It's being changed to the dimensions of re2, which is what re is when boolean is done. I'm wondering if I could get a second pair of eyes on this, someone who understands the subtleties of data_containers better than me. I've pushed the current state of things to my branch. https://bitbucket.org/sskory/yt/changeset/148e930ce903 Thanks to anyone who can spare the time, or for any comments on this idea! Let me know if you have any questions. -- Stephen Skory s@skory.us http://stephenskory.com/ 510.621.3687 (google voice)
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Stephen Skory