/// <summary>
/// Returns a CompressedPolicyVector array with the policy vectors
/// extracted from all the positions in this batch.
/// </summary>
/// <param name="numPos"></param>
/// <param name="topK"></param>
/// <param name="indices"></param>
/// <param name="probabilities"></param>
/// <param name="probType"></param>
/// <returns></returns>
static CompressedPolicyVector[] ExtractPoliciesTopK(int numPos, int topK, Span <int> indices, Span <float> probabilities, PolicyType probType)
{
if (probType == PolicyType.LogProbabilities)
{
throw new NotImplementedException();
for (int i = 0; i < indices.Length; i++)
{
probabilities[i] = MathF.Exp(probabilities[i]);
}
}
if (indices == null && probabilities == null)
{
return(null);
}
if (probabilities.Length != indices.Length)
{
throw new ArgumentException("Indices and probabilties expected to be same length");
}
CompressedPolicyVector[] retPolicies = new CompressedPolicyVector[numPos];
int offset = 0;
for (int i = 0; i < numPos; i++)
{
CompressedPolicyVector.Initialize(ref retPolicies[i], indices.Slice(offset, topK), probabilities.Slice(offset, topK));
offset += topK;
}
return(retPolicies);
}
static CompressedPolicyVector[] ExtractPoliciesBufferFlat(int numPos, float[] policyProbs, PolicyType probType, bool alreadySorted)
{
// TODO: possibly needs work.
// Do we handle WDL correctly? Do we flip the moves if we are black (using positions) ?
if (policyProbs == null)
{
return(null);
}
if (policyProbs.Length != EncodedPolicyVector.POLICY_VECTOR_LENGTH * numPos)
{
throw new ArgumentException("Wrong policy size");
}
CompressedPolicyVector[] retPolicies = new CompressedPolicyVector[numPos];
if (policyProbs.Length != EncodedPolicyVector.POLICY_VECTOR_LENGTH * numPos)
{
throw new ArgumentException("Wrong policy size");
}
float[] buffer = new float[EncodedPolicyVector.POLICY_VECTOR_LENGTH];
for (int i = 0; i < numPos; i++)
{
int startIndex = EncodedPolicyVector.POLICY_VECTOR_LENGTH * i;
if (probType == PolicyType.Probabilities)
{
Array.Copy(policyProbs, startIndex, buffer, 0, EncodedPolicyVector.POLICY_VECTOR_LENGTH);
}
else
{
// Avoid overflow by subtracting off max
float max = 0.0f;
for (int j = 0; j < EncodedPolicyVector.POLICY_VECTOR_LENGTH; j++)
{
float val = policyProbs[startIndex + j];
if (val > max)
{
max = val;
}
}
for (int j = 0; j < EncodedPolicyVector.POLICY_VECTOR_LENGTH; j++)
{
buffer[j] = (float)Math.Exp(policyProbs[startIndex + j] - max); // TODO: make faster
}
}
double acc = 0;
for (int j = 0; j < EncodedPolicyVector.POLICY_VECTOR_LENGTH; j++)
{
acc += buffer[j];
}
if (acc == 0.0)
{
throw new Exception("Sum of unnormalized probabilities was zero.");
}
// As performance optimization, only adjust if significantly different from 1.0
const float MAX_DEVIATION = 0.001f;
if (acc < 1.0f - MAX_DEVIATION || acc > 1.0f + MAX_DEVIATION)
{
for (int j = 0; j < EncodedPolicyVector.POLICY_VECTOR_LENGTH; j++)
{
buffer[j] = (float)(buffer[j] / acc);
}
}
CompressedPolicyVector.Initialize(ref retPolicies[i], buffer, alreadySorted);
}
return(retPolicies);
}