The problem I encounter is that, by using ndarray.view(np.dtype)
to get a structured array from a classic ndarray seems to miscompute the float
to int
conversion.
Example talks better:
In [12]: B
Out[12]:
array([[ 1.00000000e+00, 1.00000000e+00, 0.00000000e+00,
0.00000000e+00, 4.43600000e+01, 0.00000000e+00],
[ 1.00000000e+00, 2.00000000e+00, 7.10000000e+00,
1.10000000e+00, 4.43600000e+01, 1.32110000e+02],
[ 1.00000000e+00, 3.00000000e+00, 9.70000000e+00,
2.10000000e+00, 4.43600000e+01, 2.04660000e+02],
...,
[ 1.28900000e+03, 1.28700000e+03, 0.00000000e+00,
9.99999000e+05, 4.75600000e+01, 3.55374000e+03],
[ 1.28900000e+03, 1.28800000e+03, 1.29000000e+01,
5.40000000e+00, 4.19200000e+01, 2.08400000e+02],
[ 1.28900000e+03, 1.28900000e+03, 0.00000000e+00,
0.00000000e+00, 4.19200000e+01, 0.00000000e+00]])
In [14]: B.view(A.dtype)
Out[14]:
array([(4607182418800017408, 4607182418800017408, 0.0, 0.0, 44.36, 0.0),
(4607182418800017408, 4611686018427387904, 7.1, 1.1, 44.36, 132.11),
(4607182418800017408, 4613937818241073152, 9.7, 2.1, 44.36, 204.66),
...,
(4653383897399164928, 4653375101306142720, 0.0, 999999.0, 47.56, 3553.74),
(4653383897399164928, 4653379499352653824, 12.9, 5.4, 41.92, 208.4),
(4653383897399164928, 4653383897399164928, 0.0, 0.0, 41.92, 0.0)],
dtype=[('i', '<i8'), ('j', '<i8'), ('tnvtc', '<f8'), ('tvtc', '<f8'), ('tf', '<f8'), ('tvps', '<f8')])
The 'i' and 'j' columns are true integers:
Here you have two further check I have done, the problem seems to come from the ndarray.view(np.int)
In [21]: B[:,:2]
Out[21]:
array([[ 1.00000000e+00, 1.00000000e+00],
[ 1.00000000e+00, 2.00000000e+00],
[ 1.00000000e+00, 3.00000000e+00],
...,
[ 1.28900000e+03, 1.28700000e+03],
[ 1.28900000e+03, 1.28800000e+03],
[ 1.28900000e+03, 1.28900000e+03]])
In [22]: B[:,:2].view(np.int)
Out[22]:
array([[4607182418800017408, 4607182418800017408],
[4607182418800017408, 4611686018427387904],
[4607182418800017408, 4613937818241073152],
...,
[4653383897399164928, 4653375101306142720],
[4653383897399164928, 4653379499352653824],
[4653383897399164928, 4653383897399164928]])
In [23]: B[:,:2].astype(np.int)
Out[23]:
array([[ 1, 1],
[ 1, 2],
[ 1, 3],
...,
[1289, 1287],
[1289, 1288],
[1289, 1289]])
What am I doing wrong? Can't I change the type due to numpy allocation memory? Is there another way to do this (fromarrays, was accusing a shape mismatch
?