[Numpy-discussion] numarray memmap

Sebastian Haase haase at msg.ucsf.edu
Wed Dec 3 10:48:02 CST 2003


Hi,
I would like to use memmap array more often - here are some comments:
(Please look for lines with $$$$)

>>> from numarray import memmap as mm
>>> m = mm.open("C:/mm1", mode='w+', len=0)
>>> n = m.insert(0,0)
>>> a = na.array(buffer=n)
X:\PrWin\wxPython\lib\PyCrust\PyCrustApp.py:1: DeprecationWarning: The
'buffer' keyword is deprecated.  Use 'sequence' instead.
Exception exceptions.AttributeError: "Memmap instance has no attribute
'_mode'" in Traceback (most recent call last):
  File "<input>", line 1, in ?
  File "X:\PrWin\numarray\numarraycore.py", line 279, in array
    type = getTypeObject(sequence, type, typecode)
  File "X:\PrWin\numarray\numarraycore.py", line 223, in getTypeObject
    return Py2NumType[ _maxtype(sequence) ]
KeyError

$$$$ Is this a mistake on my part or should the error message be "better"
???


>>> a = na.array(buffer=n, type=na.UInt16, shape=(0,0,0))
>>> a.shape
(0, 0, 0)
>>> m
<Memmap on file 'C:/mm1' with mode='w+', length=0, 1 slices>
>>> a.resize((100,100,100))
>>> a.shape
(100, 100, 100)
>>> m.sync()
>>> m.flush()
Traceback (most recent call last):
  File "<input>", line 1, in ?
  File "X:\PrWin\numarray\memmap.py", line 501, in flush
    self._consolidate(filename)
  File "X:\PrWin\numarray\memmap.py", line 469, in _consolidate
    f.write(self._buffer(m, mlen))
  File "X:\PrWin\numarray\memmap.py", line 317, in _buffer
    raise RuntimeError("Memmap no longer valid.  (closed?)")
RuntimeError: Memmap no longer valid.  (closed?)
>>> m
<Memmap on file 'C:/mm1' with mode='w+', length=0, 1 slices>

$$$$  Is this a bug ?

My idea is to "prepare" the memmap file before I actually know the array
dimensions that should go into it.  Is that a good idea ?

Thanks,
Sebastian Haase







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