On Thursday 10 August 2006 21:32, Sebastian Haase wrote: > Travis Oliphant wrote: > > Sebastian Haase wrote: > >> Hi, > >> Does numpy.ascontiguousarray(arr) "fix" the byteorder when arr is > >> non-native byteorder ? > >> > >> If not, what functions does ? > > > > It can if you pass in a data-type with the right byteorder (or use a > > native built-in data-type). > > > > In NumPy, it's the data-type that carries the "byte-order" > > information. So, there are lot's of ways to "fix" the byte-order. > > So then the question is: what is the easiest way to say: > give me the equivalent type of dtype, but with byteorder '<' (or '=') !? > I would be cumbersome (and ugly ;-) ) if one would have to "manually > assemble" such a construct every time ...
I just found this in myCVS/numpy/numpy/core/tests/test_numerictypes.py <code> def normalize_descr(descr): "Normalize a description adding the platform byteorder." out = [] for item in descr: dtype = item[1] if isinstance(dtype, str): if dtype[0] not in ['|','<','>']: onebyte = dtype[1:] == "1" if onebyte or dtype[0] in ['S', 'V', 'b']: dtype = "|" + dtype else: dtype = byteorder + dtype if len(item) > 2 and item[2] > 1: nitem = (item[0], dtype, item[2]) else: nitem = (item[0], dtype) out.append(nitem) elif isinstance(item[1], list): l = [] for j in normalize_descr(item[1]): l.append(j) out.append((item[0], l)) else: raise ValueError("Expected a str or list and got %s" % \ (type(item))) return out </code> Is that what I was talking about !? It's quite a big animal. Would this be needed "everytime" I want to get a "systembyte-ordered version" of a given type !? - Sebastian > > > Of course there is still the difference between "fixing" the byte-order > > and simply "viewing" the memory in the correct byte-order. The former > > physically flips bytes around, the latter just flips them on calculation > > and presentation. > > I understand. I need something that I can feed into my C routines that > are to dumb to handle non-contiguous or byte-swapped data . > > - Sebastian ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Numpy-discussion mailing list Numpy-discussion@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/numpy-discussion