Hi dear Chapel devs and users,
I have a newbie question about reading a binary file in Chapel.
I downloaded the MNIST dataset with idx3 file format.
http://yann.lecun.com/exdb/mnist/
This file is composed of the structure like that:
[offset] [type] [value] [description]
0000 32 bit integer 0x00000803(2051) magic number
0004 32 bit integer 60000 number of images
0008 32 bit integer 28 number of rows
0012 32 bit integer 28 number of columns
0016 unsigned byte ?? pixel
0017 unsigned byte ?? pixel
I tried to read the beginner three integers (the magic number, the numbers
of images and the number of rows). The code used is:
module Main{
proc main(){
var f = open("train-images.idx3-ubyte", iomode.r);
var r = f.reader(kind=ionative);
var magic:uint(32);
r.read(magic);
writef("magic = %xu\n",magic);
var num_images:uint(32);
r.read(num_images);
writef("Image Number = %xu\n",num_images);
var rows:uint(32);
r.read(rows);
writef("rows = %xu\n",rows);
r.close();
f.close();
}
}
Instead of outputting:
magic = 0000803
Image Numbers = 0000ea60
rows = 0000001c
The program is outputting:
magic = 3080000
Image Numbers = 60ea0000
rows = 1c000000
The value is stored in reverse order.
Is this problem related with big-little endian?
My computer is x86_64, Intel Core I7, Ubuntu 17, Chapel 1.15.
Could you give me some advice?
Thank you very much.
Att.
Marcos Cleison
------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
Chapel-users mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/chapel-users
