RoaringBitmap
IsNegtive exist bug
When using roaring64.BSI, due to value type is *big.Int , bsi's bitCount is Variable length even if some negative value is set. Thus there is a bug, when bsi's min negative value's bitLen is less than max positive num, GetValue will get wrong error.
testcode
bsi := roaring64.NewDefaultBSI()
for i:=-100;i<100;i++ {
bsi.SetValue(uint64(i+100),int64(i))
}
fmt.Println(bsi.GetValue(0))
result is -100, true
bsi := roaring64.NewDefaultBSI()
for i:=-100;i<1000;i++ {
bsi.SetValue(uint64(i+100),int64(i))
}
fmt.Println(bsi.GetValue(0))
result is 156, true
So if code uses len(b.bA) as sign bit may not work
Hello,
Can you add a unit test that reproduces the issue?
On Wed, Nov 27, 2024 at 3:45 AM ChicChip @.***> wrote:
When using roaring64.BSI, due to value type is *big.Int , bsi's bitCount is Variable length even if some negative value is set. Thus there is a bug, when bsi's min negative value's bitLen is less than max positive num, GetValue will get wrong error.
— Reply to this email directly, view it on GitHub https://github.com/RoaringBitmap/roaring/issues/462, or unsubscribe https://github.com/notifications/unsubscribe-auth/ADZZAUXHT3GSMFANPE7NJV32CWICZAVCNFSM6AAAAABSSM5VLKVHI2DSMVQWIX3LMV43ASLTON2WKOZSGY4TOOBZGY2DGNI . You are receiving this because you are subscribed to this thread.Message ID: @.***>
- unit test will pass
func TestGetNegativeValue(t *testing.T) {
num := int64(14)
bsi := NewDefaultBSI()
for i:=-num; i<=num;i++ {
bsi.SetValue(uint64(i+num), i)
}
val, _ := bsi.GetValue(0)
assert.Equal(t, -num, val)
bsi.SetValue(uint64((num+1)+num), num+1)
val, _ = bsi.GetValue(0)
assert.Equal(t, -num, val)
}
- unit test will fail, when set value 16 to bsi, bsi's higthest bit is not sign bit
func TestGetNegativeValue(t *testing.T) {num := int64(15)bsi := NewDefaultBSI()for i:=-num; i<=num;i++ {bsi.SetValue(uint64(i+num), i)}val, _ := bsi.GetValue(0)assert.Equal(t, -num, val)bsi.SetValue(uint64((num+1)+num), num+1)val, _ = bsi.GetValue(0)assert.Equal(t, -num, val)}Error: Not equal: expected: -15 actual : 17 Test: TestGetNegativeValue --- FAIL: TestGetNegativeValue (0.00s)
Are you attempting to set columnId to a negative value?
On Wed, Nov 27, 2024 at 8:02 AM ChicChip @.***> wrote:
- unit test will pass
func TestGetNegativeValue(t *testing.T) { num := int64(14) bsi := NewDefaultBSI() for i:=-num; i<=num;i++ { bsi.SetValue(uint64(i+num), i) } val, _ := bsi.GetValue(0) assert.Equal(t, -num, val) bsi.SetValue(uint64((num+1)+num), num+1) val, _ = bsi.GetValue(0) assert.Equal(t, -num, val) }
- unit test will fail, when set value 16 to bsi, bsi's higthest bit is not sign bit func TestGetNegativeValue(t *testing.T) { num := int64(15) bsi := NewDefaultBSI() for i:=-num; i<=num;i++ { bsi.SetValue(uint64(i+num), i) } val, _ := bsi.GetValue(0) assert.Equal(t, -num, val) bsi.SetValue(uint64((num+1)+num), num+1) val, _ = bsi.GetValue(0) assert.Equal(t, -num, val) } Error: Not equal: expected: -15 actual : 17 Test: TestGetNegativeValue --- FAIL: TestGetNegativeValue (0.00s)
— Reply to this email directly, view it on GitHub https://github.com/RoaringBitmap/roaring/issues/462#issuecomment-2503958263, or unsubscribe https://github.com/notifications/unsubscribe-auth/ADZZAUTPTVSHT53FOZJRTDD2CXGHNAVCNFSM6AAAAABSSM5VLKVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDKMBTHE2TQMRWGM . You are receiving this because you commented.Message ID: @.***>
Are you attempting to set columnId to a negative value? … On Wed, Nov 27, 2024 at 8:02 AM ChicChip @.**> wrote: 1. unit test will pass func TestGetNegativeValue(t testing.T) { num := int64(14) bsi := NewDefaultBSI() for i:=-num; i<=num;i++ { bsi.SetValue(uint64(i+num), i) } val, _ := bsi.GetValue(0) assert.Equal(t, -num, val) bsi.SetValue(uint64((num+1)+num), num+1) val, _ = bsi.GetValue(0) assert.Equal(t, -num, val) } 2. unit test will fail, when set value 16 to bsi, bsi's higthest bit is not sign bit func TestGetNegativeValue(t testing.T) { num := int64(15) bsi := NewDefaultBSI() for i:=-num; i<=num;i++ { bsi.SetValue(uint64(i+num), i) } val, _ := bsi.GetValue(0) assert.Equal(t, -num, val) bsi.SetValue(uint64((num+1)+num), num+1) val, _ = bsi.GetValue(0) assert.Equal(t, -num, val) } Error: Not equal: expected: -15 actual : 17 Test: TestGetNegativeValue --- FAIL: TestGetNegativeValue (0.00s) — Reply to this email directly, view it on GitHub <#462 (comment)>, or unsubscribe https://github.com/notifications/unsubscribe-auth/ADZZAUTPTVSHT53FOZJRTDD2CXGHNAVCNFSM6AAAAABSSM5VLKVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDKMBTHE2TQMRWGM . You are receiving this because you commented.Message ID: @.>
no, in this code, you can see columnId is >=0, only value may a negtive number