I'm trying to give a better error report (possible bug) for this case (about judySArray give incorrect result, but I don't know which key that give incorrect result). The code here from this folder, note on this blog. Dependencies: judySArray.h and cedar.h
// judy.cpp
#include "deps/judySArray.h"
#include <string>
#include <iostream>
#include <cstdlib>
#include <cstring>
using namespace std;
typedef judySArray<double> MSD;
const int MAX_DATA = 12000000;
const char i2ch[] = {'0','1','2','3','4','5','6','7','8','9','a','B','c','D','e','F'};
int get_first_digit(double d) {
while(d > 10) d /= 10;
return d;
}
string to_rhex(int v) {
char hex[32];
int start = 0;
while(v>0) {
hex[start] = i2ch[v%16];
v /= 16;
++start;
}
hex[start] = 0;
return hex;
}
void add_or_inc(MSD &m, const string& key,double set, double inc, int& ctr) {
const char* cstr = key.c_str();
double it = m.find(cstr);
if(!it) {
m.insert(cstr,set);
return;
}
m.insert(cstr,it+inc);
++ctr;
}
int main() {
MSD m(64);
int dup1 = 0, dup2 = 0, dup3 = 0;
for(int z=MAX_DATA;z>0;--z) {
int val2 = MAX_DATA-z;
int val3 = MAX_DATA*2-z;
string key1 = to_string(z);
string key2 = to_string(val2);
string key3 = to_rhex(val3);
add_or_inc(m,key1,z,val2,dup1);
add_or_inc(m,key2,val2,val3,dup2);
add_or_inc(m,key3,val3,z,dup3);
}
cout << dup1 << ' ' << dup2 << ' ' << dup3 << endl;
int total = 0, verify = 0, count = 0;
for(auto &it = m.begin();m.success(); m.next()) {
total += get_first_digit(it.value);
verify += strlen((const char *) it.key);
count += 1;
}
cout << total << ' ' << verify << ' ' << count << endl;
}
other implementation (map, unordered_map, hat-trie and cedar) give correct result:
6009354 6009348 611297
36186112 159701682 23370001
but judy didn't:
6009354 6009348 611297
36186112 159701681 23370000
The problem is, which key that have incorrect result?
I've tried to build a code that insert those keys on another data structure (that is cedar), but that incorrect keys still not detected:
// judy.cpp
#include "deps/judySArray.h"
#include <string>
#include <iostream>
#include <cstdlib>
#include <cstring>
#include <vector>
using namespace std;
typedef judySArray<double> MSD;
const int MAX_DATA = 12000000;
const char i2ch[] = {'0','1','2','3','4','5','6','7','8','9','a','B','c','D','e','F'};
int get_first_digit(double d) {
while(d > 10) d /= 10;
return d;
}
string to_rhex(int v) {
char hex[32];
int start = 0;
while(v>0) {
hex[start] = i2ch[v%16];
v /= 16;
++start;
}
hex[start] = 0;
return hex;
}
void add_or_inc(MSD &m, const string& key,double set, double inc, int& ctr) {
const char* cstr = key.c_str();
double it = m.find(cstr);
if(!it) {
m.insert(cstr,set);
return;
}
m.insert(cstr,it+inc);
++ctr;
}
#include "deps/cedar.h"
class MSD2 {
public:
vector<double> data;
typedef cedar::da<int> CI;
CI da;
bool exists(const string& key,double &old) {
int idx = -1;
bool found = da.exactMatchExists(key.c_str(),key.size(),&idx);
if(found) old = data[idx];
return found;
}
void insert(const string& key,double val) {
da.update(key.c_str(),key.size(),data.size());
data.push_back(val);
}
void update(const string& key,double val) {
int idx = -1;
bool found = da.exactMatchExists(key.c_str(),key.size(),&idx);
if(found) {
data[idx] = val;
return;
}
insert(key,val);
}
};
void add_or_inc(MSD2 &m, const string& key,double set, double inc, int& ctr) {
double old;
if(!m.exists(key,old)) {
m.insert(key,set);
return;
}
m.update(key,old+inc);
++ctr;
}
int main() {
MSD m(64);
MSD2 m2;
int dup1 = 0, dup2 = 0, dup3 = 0;
int vup1 = 0, vup2 = 0, vup3 = 0;
for(int z=MAX_DATA;z>0;--z) {
int val2 = MAX_DATA-z;
int val3 = MAX_DATA*2-z;
string key1 = to_string(z);
string key2 = to_string(val2);
string key3 = to_rhex(val3);
add_or_inc(m,key1,z,val2,dup1);
add_or_inc(m,key2,val2,val3,dup2);
add_or_inc(m,key3,val3,z,dup3);
add_or_inc(m2,key1,z,val2,vup1);
add_or_inc(m2,key2,val2,val3,vup2);
add_or_inc(m2,key3,val3,z,vup3);
}
cout << dup1 << ' ' << dup2 << ' ' << dup3 << endl;
cout << vup1 << ' ' << vup2 << ' ' << vup3 << endl;
int total = 0, verify = 0, count = 0;
int xotal = 0, xerify = 0, xount = 0;
union { int i; int x; } b;
size_t from = 0, p = 0;
char key[256] = {0};
for (b.i = m2.da.begin(from, p); b.i != MSD2::CI::CEDAR_NO_PATH; b.i = m2.da.next(from, p)) {
double it2 = m2.data[b.x]; // <-- find cedar's
xotal += get_first_digit(it2);
m2.da.suffix(key,p,from);
xerify += strlen(key);
xount += 1;
double it = m.find(key); // <-- find judy's
if(it != it2) { // if value doesn't match, print:
cout << "mismatch value for " << key << " : " << it2 << " vs " << it << endl;
}
}
for(auto &it = m.begin();m.success(); m.next()) {
total += get_first_digit(it.value);
verify += strlen((const char *) it.key);
count += 1;
}
cout << total << ' ' << verify << ' ' << count << endl;
cout << xotal << ' ' << xerify << ' ' << xount << endl;
}
compile with: clang++ -std=c++11 judy-findbug.cpp (or g++ -std=c++11)
the output would be:
6009354 6009348 611297
6009354 6009348 611297
36186112 159701681 23370000 <-- judy's
36186112 159701682 23370001 <-- cedar's
cedar has one more value than judy's (that is correct), but it didn't detected by the code above..
How to find that incorrect key(s)?
The bug on the code is someone (me) uncomment the assert(value != 0).
The bug was Karl's Judy implementation should not store null values (0 value).
Solution: use Doug Baskins' Judy implementation.