def test_array_from_file():
shape = (2,3,4)
dtype = np.dtype(np.float32)
in_arr = np.arange(24, dtype=dtype).reshape(shape)
# Check on string buffers
offset = 0
yield assert_true, buf_chk(in_arr, StringIO(), None, offset)
offset = 10
yield assert_true, buf_chk(in_arr, StringIO(), None, offset)
# check on real file
fd, fname = tempfile.mkstemp()
try:
# fortran ordered
out_buf = file(fname, 'wb')
in_buf = file(fname, 'rb')
yield assert_true, buf_chk(in_arr, out_buf, in_buf, offset)
# Drop offset to check that shape's not coming from file length
out_buf.seek(0)
in_buf.seek(0)
offset = 5
yield assert_true, buf_chk(in_arr, out_buf, in_buf, offset)
finally:
os.remove(fname)
# Make sure empty shape, and zero length, give empty arrays
arr = array_from_file((), np.dtype('f8'), StringIO())
yield assert_equal, len(arr), 0
arr = array_from_file((0,), np.dtype('f8'), StringIO())
yield assert_equal, len(arr), 0
def buf_chk(in_arr, out_buf, in_buf, offset):
''' Write contents of in_arr into fileobj, read back, check same '''
instr = ' ' * offset + in_arr.tostring(order='F')
out_buf.write(instr)
out_buf.flush()
if in_buf is None: # we're using in_buf from out_buf
out_buf.seek(0)
in_buf = out_buf
arr = array_from_file(
in_arr.shape,
in_arr.dtype,
in_buf,
offset)
return np.allclose(in_arr, arr)
def write_return(data, fileobj, out_dtype, *args, **kwargs):
fileobj.truncate(0)
array_to_file(data, out_dtype, fileobj, *args, **kwargs)
data = array_from_file(data.shape, out_dtype, fileobj)
return data