[MATRIX-SIG] Pickling arrays on a DEC Alpha

[Konrad Hinsen]

Here's a quick hack for those who want to exchange pickle files between
DEC Alphas and other machines (with 32-bit longs). If you replace the
functions LoadArray() and DumpArray() in Numeric.py, arrays of longs
will always be saved and retrieved in 32-bit format, even on Alphas.
The modification doesn't make any difference on non-Alpha machines.

---------------------------------------------------------------------------
def DumpArray(m, fp):    
	s = m.shape
	if LittleEndian: endian = "L"
	else: endian = "B"
	typecode = m.typecode()
	# Save 64-int arrays (DEC Alpha) as 32 bit for compatibility
	if typecode == 'l' and m.itemsize() == 8:
	    m = m.astype('i')
	fp.write("A%s%s%d " % (typecode, endian, m.itemsize()))
	for d in s:
		fp.write("%d "% d)
	fp.write('\n')
	fp.write(m.tostring())

SizeOfLong = zeros((1,), 'l').itemsize()

def LoadArray(fp):
	ln = string.split(fp.readline())
	if ln[0][0] == 'A': ln[0] = ln[0][1:] # Nasty hack showing my ignorance of pickle
	typecode = ln[0][0]
	endian = ln[0][1]
	
	shape = map(lambda x: string.atoi(x), ln[1:])
	itemsize = string.atoi(ln[0][2:])

	sz = reduce(multiply, shape)*itemsize
	data = fp.read(sz)

	# Read 32-bit arrays as int (not long) on DEC Alphas
	if typecode == 'l' and itemsize == 4 and SizeOfLong == 8:
	    m = fromstring(data, 'i').astype('l')
	else:
	    m = fromstring(data, typecode)
	m = reshape(m, shape)

	if (LittleEndian and endian == 'B') or (not LittleEndian and endian == 'L'):
		return m.byteswapped()
	else:
		return m
---------------------------------------------------------------------------

-- 
-------------------------------------------------------------------------------
Konrad Hinsen                          | E-Mail: hinsen@ibs.ibs.fr
Laboratoire de Dynamique Moleculaire   | Tel.: +33-4.76.88.99.28
Institut de Biologie Structurale       | Fax:  +33-4.76.88.54.94
41, av. des Martyrs                    | Deutsch/Esperanto/English/
38027 Grenoble Cedex 1, France         | Nederlands/Francais
-------------------------------------------------------------------------------

_______________
MATRIX-SIG  - SIG on Matrix Math for Python

send messages to: matrix-sig@python.org
administrivia to: matrix-sig-request@python.org
_______________