Resolved NativeMultiHashMap<TKey, TValue> GetKeyArray returns IndexOutOfRangeException

Hi.
I am very new to Burst and Jobs.
What do you think I am doing wrong?
Thank you for your time.
1. I am converting a NativeArray to a NativeMultiHashMap

Code (CSharp):

1. NativeMultiHashMap<Vector3, Vector2> r = new NativeMultiHashMap<Vector3, Vector2>(args[0], Allocator.TempJob);
2. tbThreaded tbJob = new tbThreaded
3. {
4.     df = new NativeSlice<dFiltered>(cpData,0,args[0]),
5.     results = r
6. };
7. JobHandle handle = tbJob.Schedule(args[0], 32);
8. handle.Complete();
9.  

using this Job

Code (CSharp):

1. [BurstCompile(CompileSynchronously = true)]
2. public struct tbThreaded: IJobParallelFor
3. {
4.     [ReadOnly]
5.     public NativeSlice<dFiltered> df;
6.     [NativeDisableParallelForRestriction]
7.     public NativeMultiHashMap<Vector3, Vector2> results;
8.     public void Execute(int i)
9.     {
10.         results.Add(df[i].dValue,df[i].pPosition);
11.     }    
12. }

dFiltered struct:

Code (CSharp):

1. public struct dFiltered
2. {
3.     public Vector3 dValue;
4.     public Vector2 pPosition;
5. }

When I call

r.GetKeyArray(Allocator.TempJob);

I get

Spoiler: Error Message

IndexOutOfRangeException: Index 626 is out of range of '626' Length.
Unity.Collections.NativeArray`1[T].FailOutOfRangeError (System.Int32 index) (at <60a316878f2f47b5ad8b2d4c8c6c52c0>:0)
Unity.Collections.NativeArray`1[T].CheckElementWriteAccess (System.Int32 index) (at <60a316878f2f47b5ad8b2d4c8c6c52c0>:0)
Unity.Collections.NativeArray`1[T].set_Item (System.Int32 index, T value) (at <60a316878f2f47b5ad8b2d4c8c6c52c0>:0)
Unity.Collections.LowLevel.Unsafe.UnsafeHashMapData.GetKeyArray[TKey] (Unity.Collections.LowLevel.Unsafe.UnsafeHashMapData* data, Unity.Collections.NativeArray`1[T] result) (at Library/PackageCache/com.unity.collections@0.15.0-preview.21/Unity.Collections/UnsafeHashMap.cs:330)
Unity.Collections.LowLevel.Unsafe.UnsafeMultiHashMap`2[TKey,TValue].GetKeyArray (Unity.Collections.Allocator allocator) (at Library/PackageCache/com.unity.collections@0.15.0-preview.21/Unity.Collections/UnsafeMultiHashMap.cs:256)
Unity.Collections.NativeMultiHashMap`2[TKey,TValue].GetKeyArray (Unity.Collections.Allocator allocator) (at Library/PackageCache/com.unity.collections@0.15.0-preview.21/Unity.Collections/NativeMultiHashMap.cs:314)
BBTight.Start () (at Assets/Resources/Test Scripts/pass/BBTight.cs:76)

 

You're disabling safety on your hash map then writing to it in parallel? That is completely unsafe and will corrupt your hash map.

Hash map supports parallel writing, use pass in hashmap.AsParallelWriter instead.

Until you are comfortable with what you're doing, don't turn off safety. It's there to protect you and stop you doing things that aren't safe, like this.

 

Hey, thank you, it fixed the problem.
To anyone who stumbles upon this thread, the fixed code:

Code (CSharp):

1. NativeMultiHashMap<Vector3, Vector2> r = new NativeMultiHashMap<Vector3, Vector2>(args[0], Allocator.TempJob);
2. tbThreaded tbJob = new tbThreaded
3. {
4.     df = new NativeSlice<dFiltered>(cpData,0,args[0]),
5.     results = r.AsParallelWriter()
6. };
7. JobHandle handle = tbJob.Schedule(args[0], 32);
8. handle.Complete();

and

Code (CSharp):

1. [BurstCompile(CompileSynchronously = true)]
2. public struct tbThreaded: IJobParallelFor
3. {
4.     [ReadOnly]
5.     public NativeSlice<dFiltered> df;
6.     [NativeDisableParallelForRestriction]
7.     public NativeMultiHashMap<Vector3, Vector2>.ParallelWriter results;
8.     public void Execute(int i)
9.     {
10.         results.Add(df[i].dValue,df[i].pPosition);
11.     }  
12. }