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Overview
| Comment: | Improved rendering of LogEst values corresponding to real values near 0.0 in the tool/logest.c utility program. |
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| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | experimental-costs |
| Files: | files | file ages | folders |
| SHA1: |
32910c8c595858245bb7ecfe3aa0f90e |
| User & Date: | drh 2014-04-30 14:22:38 |
Context
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2014-04-30
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| 14:47 | Fix a couple of out-of-date comments in where.c. (check-in: eefeda32 user: dan tags: experimental-costs) | |
| 14:22 | Improved rendering of LogEst values corresponding to real values near 0.0 in the tool/logest.c utility program. (check-in: 32910c8c user: drh tags: experimental-costs) | |
| 13:19 | Fix long-standing typos in comments. (check-in: b9f91317 user: drh tags: experimental-costs) | |
Changes
Changes to tool/logest.c.
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return (n+8)>>(3-x);
}
static LogEst logEstFromDouble(double x){
sqlite3_uint64 a;
LogEst e;
assert( sizeof(x)==8 && sizeof(a)==8 );
if( x<=0.0 ) return -32768;
if( x<1.0 ) return -logEstFromDouble(1/x);
if( x<1024.0 ) return logEstFromInteger((sqlite3_uint64)(1024.0*x)) - 100;
if( x<=2000000000.0 ) return logEstFromInteger((sqlite3_uint64)x);
memcpy(&a, &x, 8);
e = (a>>52) - 1022;
return e*10;
}
................................................................................
}else if( isFloat(z) && z[0]!='-' ){
a[n++] = logEstFromDouble(atof(z));
}else{
showHelp(argv[0]);
}
}
for(i=n-1; i>=0; i--){
if( a[i]<0 ){
printf("%5d (%f)\n", a[i], 1.0/(double)logEstToInt(-a[i]));
}else{
sqlite3_uint64 x = logEstToInt(a[i]+100)*100/1024;
printf("%5d (%lld.%02lld)\n", a[i], x/100, x%100);
}
}
return 0;
}
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return (n+8)>>(3-x);
}
static LogEst logEstFromDouble(double x){
sqlite3_uint64 a;
LogEst e;
assert( sizeof(x)==8 && sizeof(a)==8 );
if( x<=0.0 ) return -32768;
if( x<0.01 ) return -logEstFromDouble(1.0/x);
if( x<1.0 ) return logEstFromDouble(100.0*x) - 66;
if( x<1024.0 ) return logEstFromInteger((sqlite3_uint64)(1024.0*x)) - 100;
if( x<=2000000000.0 ) return logEstFromInteger((sqlite3_uint64)x);
memcpy(&a, &x, 8);
e = (a>>52) - 1022;
return e*10;
}
................................................................................
}else if( isFloat(z) && z[0]!='-' ){
a[n++] = logEstFromDouble(atof(z));
}else{
showHelp(argv[0]);
}
}
for(i=n-1; i>=0; i--){
if( a[i]<-40 ){
printf("%5d (%f)\n", a[i], 1.0/(double)logEstToInt(-a[i]));
}else if( a[i]<10 ){
printf("%5d (%f)\n", a[i], logEstToInt(a[i]+100)/1024.0);
}else{
sqlite3_uint64 x = logEstToInt(a[i]+100)*100/1024;
printf("%5d (%lld.%02lld)\n", a[i], x/100, x%100);
}
}
return 0;
}
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