https://stackoverflow.com/questions/54545228/is-there-a-memory-limit-on-np-fromfile-method
由于安装32bit python导致的问题
解决方案:安装64bit python
I am trying to read a big file into array with the help of np.fromfile()
, however, after certain number of bytes it gives MemoryError.
with open(filename,'r') as file: data = np.fromfile(file, dtype=np.uint16, count=2048*2048*63) data = data.reshape(63, 2048, 2048)
It works fine with 2048*2048*63 however not working with 2048*2048*64. How to debug this? I am wondering what is the bottleneck here?
Edit: I am running on Windows 10, RAM 256GB, it is a standalone script, 64bit Python.
Edit2: I followed the advices on comments, now getting the error at 128*2048*2048, works fine with 127*2048*2048.
pythonnumpymemory se-share-sheet#willShow s-popover:shown->se-share-sheet#didShow" data-controller="se-share-sheet s-popover" data-gps-track="post.click({ item: 2, priv: 0, post_type: 1 })" data-s-popover-placement="bottom-start" data-se-share-sheet-license-name="CC BY-SA 4.0" data-se-share-sheet-license-url="https%3a%2f%2fcreativecommons.org%2flicenses%2fby-sa%2f4.0%2f" data-se-share-sheet-location="1" data-se-share-sheet-post-type="question" data-se-share-sheet-social="facebook twitter devto" data-se-share-sheet-subtitle="" data-se-share-sheet-title="Share a link to this question" title="Short permalink to this question" href="https://stackoverflow.com/q/54545228" rel="external nofollow" target="_blank">Share Improve this question edited Feb 6 '19 at 1:07 asked Feb 6 '19 at 0:50 CanCode 9522 silver badges99 bronze badgesDespite what you believe, you've installed a 32 bit version of Python on your 64 bit operating system, which means virtual address space is limited to only have 2 GB in user mode, and attempts to allocate contiguous blocks of a GB or more can easily fail due to address space fragmentation.
The giveaway is your sys.maxsize
, which is just the largest value representable by a C ssize_t
in your build of Python. 2147483647
corresponds to 2**31 - 1
, which is the expected value on 32 bit Python. A 64 bit build would report 9223372036854775807
(2**63 - 1
).
Uninstall the 32 bit version of Python and download/install a 64 bit version (link is to 3.7.2 download page) (look for the installer to be labelled as x86-64, not x86; the file name would include amd64
). Annoyingly, the main page for downloading Python defaults to offering the 32 bit version for Windows, so you have to scroll down to the links to specific version download pages, click on the latest, then scroll down to the complete list by OS and bittedness and choose appropriately.
data.reshape
fromnp.reshape
). While it's unlikely to matter, it would be useful to know what OS and specific Python version you're running. – ShadowRanger Feb 6 '19 at 0:59