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Diffstat (limited to 'doc/neps')
| -rw-r--r-- | doc/neps/npy-format.rst | 23 |
1 files changed, 20 insertions, 3 deletions
diff --git a/doc/neps/npy-format.rst b/doc/neps/npy-format.rst index f7bb799f2..bf88c3fee 100644 --- a/doc/neps/npy-format.rst +++ b/doc/neps/npy-format.rst @@ -199,6 +199,21 @@ bytes of the array. Consumers can figure out the number of bytes by multiplying the number of elements given by the shape (noting that shape=() means there is 1 element) by dtype.itemsize. +Format Specification: Version 1.0 +--------------------------------- + +The version 1.0 format only allowed the array header to have a +total size of 65535 bytes. This can be exceeded by structured +arrays with a large number of columns. The version 2.0 format +extends the header size to 4 GiB. `numpy.save` will automatically +save in 2.0 format if the data requires it, else it will always use +the more compatible 1.0 format. + +The description of the fourth element of the header therefore has +become: + + The next 4 bytes form a little-endian unsigned int: the length + of the header data HEADER_LEN. Conventions ----------- @@ -269,13 +284,15 @@ the file format. Implementation -------------- -The current implementation is included in the 1.0.5 release of numpy. - - http://github.com/numpy/numpy/blob/v1.5.0/numpy/lib/format.py +The version 1.0 implementation was first included in the 1.0.5 release of +numpy, and remains available. The version 2.0 implementation was first +included in the 1.9.0 release of numpy. Specifically, the file format.py in this directory implements the format as described here. + http://github.com/numpy/numpy/blob/master/numpy/lib/format.py + References ---------- |