Created
May 21, 2013 14:35
Read MNIST Database (handwritten digits)
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// Read MNIST Database (handwritten digits) | |
// | |
// Usage: | |
// 1. download | |
// train-images-idx3-ubyte.gz | |
// train-labels-idx2-ubyte.gz | |
// from | |
// http://yann.lecun.com/exdb/mnist/ | |
// and extract them. | |
// | |
// 2. ./a | |
// | |
#include <iostream> | |
#include <cstdio> | |
#include <cstdlib> | |
#include <cmath> | |
#include <map> | |
#include <vector> | |
#include <cstring> | |
#include <functional> | |
#include <algorithm> | |
#include <cassert> | |
using namespace std; | |
#define ALL(c) c.begin(), c.end() | |
#define FOR(i,c) for(typeof(c.begin())i=c.begin();i!=c.end();++i) | |
#define REP(i,n) for(int i=0;i<n;++i) | |
#define fst first | |
#define snd second | |
void endianSwap(unsigned int &x) { | |
x = (x>>24)|((x<<8)&0x00FF0000)|((x>>8)&0x0000FF00)|(x<<24); | |
} | |
typedef vector<unsigned int> Image; | |
int main() { | |
FILE *fimage = fopen("train-images.idx3-ubyte", "rb"); | |
FILE *flabel = fopen("train-labels.idx1-ubyte", "rb"); | |
assert(fimage); | |
assert(flabel); | |
unsigned int magic, num, row, col; | |
fread(&magic, 4, 1, fimage); | |
assert(magic == 0x03080000); | |
fread(&magic, 4, 1, flabel); | |
assert(magic == 0x01080000); | |
fread(&num, 4, 1, flabel); // dust | |
fread(&num, 4, 1, fimage); endianSwap(num); | |
fread(&row, 4, 1, fimage); endianSwap(row); | |
fread(&col, 4, 1, fimage); endianSwap(col); | |
printf("num %d\n", num); | |
printf("col %d\n", col); | |
printf("row %d\n", row); | |
REP(k, 10) { //num) { | |
printf("---\n"); | |
Image img(col*row); | |
REP(i, col) REP(j, row) | |
fread(&img[i*row+j], 1, 1, fimage); | |
unsigned char label = 0; | |
fread(&label, 1, 1, flabel); | |
REP(i, col) { | |
REP(j, row) | |
printf("%02x", img[i*row+j]); | |
printf("\n"); | |
} | |
printf(" label = %x\n", label); | |
} | |
} |
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