<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Dear yt users,<div class=""><br class=""></div><div class="">I have an issue when I'm trying to load a RAMSES snapshot, which I think comes about because the snapshot is too large (51GB, code below). I have been able to successfully load several smaller simulation with yt.</div><div class=""><br class=""></div><div class="">Is there any way to circumvent this issue, for example by just loading a small part of the simulation into yt? I have tried to use some data objects to pick out regions of interest (ds.sphere, ds.box) but to no avail.</div><div class=""><br class=""></div><div class="">I have also considered just reading out the raw data from a region of interest like I usually do, and then read it into yt as a generic mesh, but it appears that you cannot do this in yt for an oct-tree AMR, only layered AMR.</div><div class=""><br class=""></div><div class="">If anyone have any insight as to how I might process I would be very grateful.</div><div class=""><br class=""></div><div class="">I use yt ver 3.2.3</div><div class=""><br class=""></div><div class="">Best,</div><div class="">Søren</div><div class=""><br class=""></div><div class=""><font face="Courier New" class="">#####################################################</font></div><div class=""><font face="Courier New" class="">#####################################################</font></div><div class=""><font face="Courier New" class="">#####################################################</font></div><div class=""><font face="Courier New" class="">import yt</font></div><div class=""><font face="Courier New" class=""><br class=""></font></div><div class=""><font face="Courier New" class="">ds = yt.load('./output_00400/info_00400.txt')</font></div><div class=""><font face="Courier New" class="">yt : [INFO ] 2016-04-15 16:18:45,575 Parameters: current_time = 403509140194502.0</font></div><div class=""><font face="Courier New" class=""><br class="">yt : [INFO ] 2016-04-15 16:18:45,575 Parameters: domain_dimensions = [512 512 512]<br class="">yt : [INFO ] 2016-04-15 16:18:45,576 Parameters: domain_left_edge = [ 0. 0. 0.]<br class="">yt : [INFO ] 2016-04-15 16:18:45,577 Parameters: domain_right_edge = [ 1. 1. 1.]<br class="">yt : [INFO ] 2016-04-15 16:18:45,577 Parameters: cosmological_simulation = 0<br class=""></font></div><div class=""><font face="Courier New" class=""><br class=""></font></div><div class=""><font face="Courier New" class="">ds.index</font></div><div class=""><font face="Courier New" class=""><br class=""></font></div><div class=""><font face="Courier New" class="">---------------------------------------------------------------------------<br class="">error Traceback (most recent call last)<br class=""><ipython-input-3-2b95fa135b88> in <module>()<br class="">----> 1 ds.index<br class=""><br class="">/astro/sfrimann/miniconda3/lib/python3.5/site-packages/yt/data_objects/static_output.py in index(self)<br class=""> 319 raise RuntimeError("You should not instantiate Dataset.")<br class=""> 320 self._instantiated_index = self._index_class(<br class="">--> 321 self, dataset_type=self.dataset_type)<br class=""> 322 # Now we do things that we need an instantiated index for<br class=""> 323 # ...first off, we create our field_info now.<br class=""><br class="">/astro/sfrimann/miniconda3/lib/python3.5/site-packages/yt/frontends/ramses/data_structures.py in __init__(self, ds, dataset_type)<br class=""> 349 <br class=""> 350 self.float_type = np.float64<br class="">--> 351 super(RAMSESIndex, self).__init__(ds, dataset_type)<br class=""> 352 <br class=""> 353 def _initialize_oct_handler(self):<br class=""><br class="">/astro/sfrimann/miniconda3/lib/python3.5/site-packages/yt/geometry/geometry_handler.py in __init__(self, ds, dataset_type)<br class=""> 55 <br class=""> 56 mylog.debug("Setting up domain geometry.")<br class="">---> 57 self._setup_geometry()<br class=""> 58 <br class=""> 59 mylog.debug("Initializing data grid data IO")<br class=""><br class="">/astro/sfrimann/miniconda3/lib/python3.5/site-packages/yt/geometry/oct_geometry_handler.py in _setup_geometry(self)<br class=""> 41 def _setup_geometry(self):<br class=""> 42 mylog.debug("Initializing Octree Geometry Handler.")<br class="">---> 43 self._initialize_oct_handler()<br class=""> 44 <br class=""> 45 def get_smallest_dx(self):<br class=""><br class="">/astro/sfrimann/miniconda3/lib/python3.5/site-packages/yt/frontends/ramses/data_structures.py in _initialize_oct_handler(self)<br class=""> 353 def _initialize_oct_handler(self):<br class=""> 354 self.domains = [RAMSESDomainFile(self.dataset, i + 1)<br class="">--> 355 for i in range(self.dataset['ncpu'])]<br class=""> 356 total_octs = sum(dom.local_oct_count #+ dom.ngridbound.sum()<br class=""> 357 for dom in self.domains)<br class=""><br class="">/astro/sfrimann/miniconda3/lib/python3.5/site-packages/yt/frontends/ramses/data_structures.py in <listcomp>(.0)<br class=""> 353 def _initialize_oct_handler(self):<br class=""> 354 self.domains = [RAMSESDomainFile(self.dataset, i + 1)<br class="">--> 355 for i in range(self.dataset['ncpu'])]<br class=""> 356 total_octs = sum(dom.local_oct_count #+ dom.ngridbound.sum()<br class=""> 357 for dom in self.domains)<br class=""><br class="">/astro/sfrimann/miniconda3/lib/python3.5/site-packages/yt/frontends/ramses/data_structures.py in __init__(self, ds, domain_id)<br class=""> 62 for t in ['grav', 'hydro', 'part', 'amr']:<br class=""> 63 setattr(self, "%s_fn" % t, basename % t)<br class="">---> 64 self._read_amr_header()<br class=""> 65 self._read_hydro_header()<br class=""> 66 self._read_particle_header()<br class=""><br class="">/astro/sfrimann/miniconda3/lib/python3.5/site-packages/yt/frontends/ramses/data_structures.py in _read_amr_header(self)<br class=""> 183 f = open(self.amr_fn, "rb")<br class=""> 184 for header in ramses_header(hvals):<br class="">--> 185 hvals.update(fpu.read_attrs(f, header))<br class=""> 186 # That's the header, now we skip a few.<br class=""> 187 hvals['numbl'] = np.array(hvals['numbl']).reshape(<br class=""><br class="">/astro/sfrimann/miniconda3/lib/python3.5/site-packages/yt/utilities/fortran_utils.py in read_attrs(f, attrs, endian)<br class=""> 72 net_format += "".join(["I"] + ([t] * n) + ["I"])<br class=""> 73 size = struct.calcsize(net_format)<br class="">---> 74 vals = list(struct.unpack(net_format, f.read(size)))<br class=""> 75 vv = {}<br class=""> 76 for a, n, t in attrs:<br class=""><br class="">error: unpack requires a bytes object of length 61253615840</font></div><div class=""><font face="Courier New" class="">#####################################################</font></div><div class=""><font face="Courier New" class="">#####################################################</font></div><div class=""><font face="Courier New" class="">#####################################################</font><br class=""><br class=""></div></body></html>