/// <summary>
/// Describes how the transformer handles one input-output column pair.
/// </summary>
/// <param name="input">Name of the input column.</param>
/// <param name="output">Name of the column resulting from the transformation of <paramref name="input"/>. Null means <paramref name="input"/> is replaced.</param>
/// <param name="colors">What colors to extract.</param>
/// <param name="interleave"></param>
/// <param name="scale">Scale color pixel value by this amount.</param>
/// <param name="offset">Offset color pixel value by this amount.</param>
/// <param name="asFloat">Output array as float array. If false, output as byte array.</param>
public ColumnInfo(string input, string output = null,
ColorBits colors = Defaults.Colors,
bool interleave = Defaults.Interleave,
float scale = Defaults.Scale,
float offset = Defaults.Offset,
bool asFloat = Defaults.Convert)
{
Contracts.CheckNonWhiteSpace(input, nameof(input));
Input = input;
Output = output ?? input;
Colors = colors;
if ((Colors & ColorBits.Alpha) == ColorBits.Alpha)
{
Planes++;
}
if ((Colors & ColorBits.Red) == ColorBits.Red)
{
Planes++;
}
if ((Colors & ColorBits.Green) == ColorBits.Green)
{
Planes++;
}
if ((Colors & ColorBits.Blue) == ColorBits.Blue)
{
Planes++;
}
Contracts.CheckParam(Planes > 0, nameof(colors), "Need to use at least one color plane");
Interleave = interleave;
AsFloat = asFloat;
if (!AsFloat)
{
Offset = Defaults.Offset;
Scale = Defaults.Scale;
}
else
{
Offset = offset;
Scale = scale;
}
Contracts.CheckParam(FloatUtils.IsFinite(Offset), nameof(offset));
Contracts.CheckParam(FloatUtils.IsFiniteNonZero(Scale), nameof(scale));
}
public ColInfoEx(Column item, Arguments args)
{
if (item.ContainsAlpha ?? args.ContainsAlpha) { Colors |= ColorBits.Alpha; Planes++; }
if (item.ContainsRed ?? args.ContainsRed) { Colors |= ColorBits.Red; Planes++; }
if (item.ContainsGreen ?? args.ContainsGreen) { Colors |= ColorBits.Green; Planes++; }
if (item.ContainsBlue ?? args.ContainsBlue) { Colors |= ColorBits.Blue; Planes++; }
Contracts.CheckUserArg(Planes > 0, nameof(item.ContainsRed), "Need to use at least one color plane");
Interleave = item.InterleaveArgb ?? args.InterleaveArgb;
Width = item.ImageWidth ?? args.ImageWidth;
Height = item.ImageHeight ?? args.ImageHeight;
Offset = item.Offset ?? args.Offset ?? 0;
Scale = item.Scale ?? args.Scale ?? 1;
Contracts.CheckUserArg(FloatUtils.IsFinite(Offset), nameof(item.Offset));
Contracts.CheckUserArg(FloatUtils.IsFiniteNonZero(Scale), nameof(item.Scale));
}
public override bool Accept()
{
if (!base.Accept())
{
return(false);
}
if (_get != null)
{
_get(ref Features);
if (!_keepBad && !FloatUtils.IsFinite(Features.Values, Features.Count))
{
_badCount++;
return(false);
}
}
return(true);
}
/// <summary>
/// print the linear model as code
/// </summary>
public static void SaveAsCode(TextWriter writer, ref VBuffer <Float> weights, Float bias,
RoleMappedSchema schema, string codeVariable = "output")
{
Contracts.CheckValue(writer, nameof(writer));
Contracts.CheckValueOrNull(schema);
var featureNames = default(VBuffer <ReadOnlyMemory <char> >);
MetadataUtils.GetSlotNames(schema, RoleMappedSchema.ColumnRole.Feature, weights.Length, ref featureNames);
int numNonZeroWeights = 0;
writer.Write(codeVariable);
writer.Write(" = ");
VBufferUtils.ForEachDefined(ref weights,
(idx, value) =>
{
if (Math.Abs(value - 0) >= Epsilon)
{
if (numNonZeroWeights > 0)
{
writer.Write(" + ");
}
writer.Write(FloatUtils.ToRoundTripString(value));
writer.Write("*");
if (featureNames.Count > 0)
{
writer.Write(FeatureNameAsCode(featureNames.GetItemOrDefault(idx).ToString(), idx));
}
else
{
writer.Write("f_" + idx);
}
numNonZeroWeights++;
}
});
if (numNonZeroWeights > 0)
{
writer.Write(" + ");
}
writer.Write(FloatUtils.ToRoundTripString(bias));
writer.WriteLine(";");
}
private float getEffectiveWeightFromBody(Rigidbody body3D, Rigidbody2D body2D)
{
if (!body2D && !body3D)
{
return(0f);
}
Vector3 velocity = body2D ? (Vector3)body2D.velocity : body3D.velocity;
float mass = body2D ? body2D.mass : body3D.mass;
bool colliderIsNull = body2D ? !body2D.GetComponent <Collider2D>() : !body3D.GetComponent <Collider>();
bool colliderIsTrigger = !colliderIsNull && (body2D ? body2D.GetComponent <Collider2D>().isTrigger : body3D.GetComponent <Collider>().isTrigger);
if (FloatUtils.IsFirstFloatPreciselySmallerOrEqualToSecond(Mathf.Abs(velocity.y), 0.1f) && !colliderIsNull && !colliderIsTrigger)
{
return(mass);
}
return(0);
}
private GaussianFourierSampler(IHostEnvironment env, ModelLoadContext ctx)
{
Contracts.AssertValue(env);
_host = env.Register(LoadName);
_host.AssertValue(ctx);
// *** Binary format ***
// int: sizeof(Float)
// Float: gamma
int cbFloat = ctx.Reader.ReadInt32();
_host.CheckDecode(cbFloat == sizeof(float));
_gamma = ctx.Reader.ReadFloat();
_host.CheckDecode(FloatUtils.IsFinite(_gamma));
}
void FixedUpdate()
{
moveDirection.Set(0, 0);
if (eat.dead || eat.eating)
{
return;
}
if (!FloatUtils.CloseEnough(Input.GetAxis("Horizontal"), 0f))
{
moveDirection.Set(Input.GetAxis("Horizontal") * speed, 0);
}
if (!FloatUtils.CloseEnough(Input.GetAxis("Vertical"), 0f))
{
moveDirection.Set(moveDirection.x, Input.GetAxis("Vertical") * speed);
}
if (transform.position.y < minYPosition.position.y)
{
moveDirection.Set(moveDirection.x, Mathf.Max(0, moveDirection.y));
}
rb.MovePosition(rb.position + moveDirection * Time.fixedDeltaTime);
if (moveDirection.x < 0)
{
direction = Direction.W;
}
else if (moveDirection.x > 0)
{
direction = Direction.E;
}
else if (FloatUtils.CloseEnough(moveDirection.x, 0, 0.01f))
{
direction = Direction.S;
}
if (direction != lastDirection)
{
lastDirection = direction;
anim.SetInteger("Direction", (int)direction);
}
}
// This is absolute error near zero and relative error away from zero.
private static double Diff(double d1, double d2)
{
if (d1 == d2)
{
return(0);
}
if (FloatUtils.IsFinite(d1) && FloatUtils.IsFinite(d2))
{
return(Math.Abs(d1 - d2) / Math.Max(1, Math.Max(Math.Abs(d1), Math.Abs(d2))));
}
if (double.IsNaN(d1) && double.IsNaN(d2))
{
return(0);
}
return(double.PositiveInfinity);
}
private PcaPredictor(IHostEnvironment env, ModelLoadContext ctx)
: base(env, RegistrationName, ctx)
{
// *** Binary format ***
// int: dimension (aka. number of features)
// int: rank
// bool: center
// If (center)
// Float[]: mean vector
// Float[][]: eigenvectors
_dimension = ctx.Reader.ReadInt32();
Host.CheckDecode(FloatUtils.IsFinite(_dimension));
_rank = ctx.Reader.ReadInt32();
Host.CheckDecode(FloatUtils.IsFinite(_rank));
bool center = ctx.Reader.ReadBoolByte();
if (center)
{
var meanArray = ctx.Reader.ReadFloatArray(_dimension);
Host.CheckDecode(meanArray.All(FloatUtils.IsFinite));
_mean = new VBuffer <Float>(_dimension, meanArray);
_norm2Mean = VectorUtils.NormSquared(_mean);
}
else
{
_mean = VBufferUtils.CreateEmpty <Float>(_dimension);
_norm2Mean = 0;
}
_eigenVectors = new VBuffer <Float> [_rank];
_meanProjected = new Float[_rank];
for (int i = 0; i < _rank; ++i)
{
var vi = ctx.Reader.ReadFloatArray(_dimension);
Host.CheckDecode(vi.All(FloatUtils.IsFinite));
_eigenVectors[i] = new VBuffer <Float>(_dimension, vi);
_meanProjected[i] = VectorUtils.DotProduct(ref _eigenVectors[i], ref _mean);
}
WarnOnOldNormalizer(ctx, GetType(), Host);
_inputType = new VectorType(NumberType.Float, _dimension);
}
private static double CalculateAvgLoss(IChannel ch, RoleMappedData data, bool norm, float[] linearWeights, AlignedArray latentWeightsAligned,
int latentDimAligned, AlignedArray latentSum, int[] featureFieldBuffer, int[] featureIndexBuffer, float[] featureValueBuffer, VBuffer<float> buffer, ref long badExampleCount)
{
var featureColumns = data.Schema.GetColumns(RoleMappedSchema.ColumnRole.Feature);
Func<int, bool> pred = c => featureColumns.Select(ci => ci.Index).Contains(c) || c == data.Schema.Label.Index || (data.Schema.Weight != null && c == data.Schema.Weight.Index);
var getters = new ValueGetter<VBuffer<float>>[featureColumns.Count];
float label = 0;
float weight = 1;
double loss = 0;
float modelResponse = 0;
long exampleCount = 0;
badExampleCount = 0;
int count = 0;
using (var cursor = data.Data.GetRowCursor(pred))
{
var labelGetter = cursor.GetGetter<float>(data.Schema.Label.Index);
var weightGetter = data.Schema.Weight == null ? null : cursor.GetGetter<float>(data.Schema.Weight.Index);
for (int f = 0; f < featureColumns.Count; f++)
getters[f] = cursor.GetGetter<VBuffer<float>>(featureColumns[f].Index);
while (cursor.MoveNext())
{
labelGetter(ref label);
weightGetter?.Invoke(ref weight);
float annihilation = label - label + weight - weight;
if (!FloatUtils.IsFinite(annihilation))
{
badExampleCount++;
continue;
}
if (!FieldAwareFactorizationMachineUtils.LoadOneExampleIntoBuffer(getters, buffer, norm, ref count,
featureFieldBuffer, featureIndexBuffer, featureValueBuffer))
{
badExampleCount++;
continue;
}
FieldAwareFactorizationMachineInterface.CalculateIntermediateVariables(featureColumns.Count, latentDimAligned, count,
featureFieldBuffer, featureIndexBuffer, featureValueBuffer, linearWeights, latentWeightsAligned, latentSum, ref modelResponse);
loss += weight * CalculateLoss(label, modelResponse);
exampleCount++;
}
}
return loss / exampleCount;
}
public IEnumerator ZoomOverTime(float damping, float targetZoom)
{
var currentZoom = _camera.orthographicSize;
var currentZoomVelocity = 0.0f;
while (true)
{
if (FloatUtils.IsApproximately(currentZoom, targetZoom, _zoomThreshold))
{
_camera.orthographicSize = targetZoom;
yield break;
}
currentZoom = Mathf.SmoothDamp(currentZoom, targetZoom, ref currentZoomVelocity, damping);
_camera.orthographicSize = currentZoom;
yield return(null);
}
}
private ColumnInfo(string input, string output, ColorBits colors, bool interleave, bool convert, float scale, float offset)
{
Contracts.CheckNonEmpty(input, nameof(input));
Contracts.CheckNonEmpty(output, nameof(output));
Input = input;
Output = output;
Colors = colors;
if ((Colors & ColorBits.Alpha) == ColorBits.Alpha)
{
Planes++;
}
if ((Colors & ColorBits.Red) == ColorBits.Red)
{
Planes++;
}
if ((Colors & ColorBits.Green) == ColorBits.Green)
{
Planes++;
}
if ((Colors & ColorBits.Blue) == ColorBits.Blue)
{
Planes++;
}
Contracts.CheckParam(Planes > 0, nameof(colors), "Need to use at least one color plane");
Interleave = interleave;
Convert = convert;
if (!Convert)
{
Offset = 0;
Scale = 1;
}
else
{
Offset = offset;
Scale = scale;
Contracts.CheckParam(FloatUtils.IsFinite(Offset), nameof(offset));
Contracts.CheckParam(FloatUtils.IsFiniteNonZero(Scale), nameof(scale));
}
}
/// <summary>
/// Constructs a new linear predictor.
/// </summary>
/// <param name="env">The host environment.</param>
/// <param name="name">Component name.</param>
/// <param name="weights">The weights for the linear predictor. Note that this
/// will take ownership of the <see cref="VBuffer{T}"/>.</param>
/// <param name="bias">The bias added to every output score.</param>
internal LinearPredictor(IHostEnvironment env, string name, ref VBuffer <Float> weights, Float bias)
: base(env, name)
{
Host.CheckParam(FloatUtils.IsFinite(weights.Values, weights.Count), nameof(weights), "Cannot initialize linear predictor with non-finite weights");
Host.CheckParam(FloatUtils.IsFinite(bias), nameof(bias), "Cannot initialize linear predictor with non-finite bias");
Weight = weights;
Bias = bias;
InputType = new VectorType(NumberType.Float, Weight.Length);
if (Weight.IsDense)
{
_weightsDense = Weight;
}
else
{
_weightsDenseLock = new object();
}
}
internal ColumnInfo(Column item, Arguments args)
{
Contracts.CheckValue(item, nameof(item));
Contracts.CheckValue(args, nameof(args));
Input = item.Source ?? item.Name;
Output = item.Name;
if (item.UseAlpha ?? args.UseAlpha)
{
Colors |= ColorBits.Alpha; Planes++;
}
if (item.UseRed ?? args.UseRed)
{
Colors |= ColorBits.Red; Planes++;
}
if (item.UseGreen ?? args.UseGreen)
{
Colors |= ColorBits.Green; Planes++;
}
if (item.UseBlue ?? args.UseBlue)
{
Colors |= ColorBits.Blue; Planes++;
}
Contracts.CheckUserArg(Planes > 0, nameof(item.UseRed), "Need to use at least one color plane");
Interleave = item.InterleaveArgb ?? args.InterleaveArgb;
Convert = item.Convert ?? args.Convert;
if (!Convert)
{
Offset = 0;
Scale = 1;
}
else
{
Offset = item.Offset ?? args.Offset ?? 0;
Scale = item.Scale ?? args.Scale ?? 1;
Contracts.CheckUserArg(FloatUtils.IsFinite(Offset), nameof(item.Offset));
Contracts.CheckUserArg(FloatUtils.IsFiniteNonZero(Scale), nameof(item.Scale));
}
}
protected bool TryNormalize(VBuffer <Single>[] values)
{
if (!Normalize)
{
return(true);
}
for (int i = 0; i < values.Length; i++)
{
// Leave a zero vector as all zeros. Otherwise, make the L1 norm equal to 1.
var sum = VectorUtils.L1Norm(in values[i]);
if (!FloatUtils.IsFinite(sum))
{
return(false);
}
if (sum > 0)
{
VectorUtils.ScaleBy(ref values[i], 1 / sum);
}
}
return(true);
}
/// <summary>
/// This should be overridden by derived classes. This implementation simply increments
/// _numIterExamples and dumps debug information to the console.
/// </summary>
protected virtual void ProcessDataInstance(IChannel ch, ref VBuffer <Float> feat, Float label, Float weight)
{
Contracts.Assert(FloatUtils.IsFinite(feat.Values, feat.Count));
++NumIterExamples;
#if OLD_TRACING // REVIEW: How should this be ported?
if (DebugLevel > 2)
{
Vector features = instance.Features;
Host.StdOut.Write("Instance has label {0} and {1} features:", instance.Label, features.Length);
for (int i = 0; i < features.Length; i++)
{
Host.StdOut.Write('\t');
Host.StdOut.Write(features[i]);
}
Host.StdOut.WriteLine();
}
if (DebugLevel > 1)
{
if (_numIterExamples % 5000 == 0)
{
Host.StdOut.Write('.');
if (_numIterExamples % 500000 == 0)
{
Host.StdOut.Write(" ");
Host.StdOut.Write(_numIterExamples);
if (_numIterExamples % 5000000 == 0)
{
Host.StdOut.Write(" ");
Host.StdOut.Write(DateTime.UtcNow);
}
Host.StdOut.WriteLine();
}
}
}
#endif
}
protected override float AccumulateOneGradient(ref VBuffer <float> feat, float label, float weight,
ref VBuffer <float> x, ref VBuffer <float> grad, ref float[] scores)
{
if (Utils.Size(scores) < _numClasses)
{
scores = new float[_numClasses];
}
float bias = 0;
for (int c = 0, start = _numClasses; c < _numClasses; c++, start += NumFeatures)
{
x.GetItemOrDefault(c, ref bias);
scores[c] = bias + VectorUtils.DotProductWithOffset(ref x, start, ref feat);
}
float logZ = MathUtils.SoftMax(scores, _numClasses);
float datumLoss = logZ;
int lab = (int)label;
Contracts.Assert(0 <= lab && lab < _numClasses);
for (int c = 0, start = _numClasses; c < _numClasses; c++, start += NumFeatures)
{
float probLabel = lab == c ? 1 : 0;
datumLoss -= probLabel * scores[c];
float modelProb = MathUtils.ExpSlow(scores[c] - logZ);
float mult = weight * (modelProb - probLabel);
VectorUtils.AddMultWithOffset(ref feat, mult, ref grad, start);
// Due to the call to EnsureBiases, we know this region is dense.
Contracts.Assert(grad.Count >= BiasCount && (grad.IsDense || grad.Indices[BiasCount - 1] == BiasCount - 1));
grad.Values[c] += mult;
}
Contracts.Check(FloatUtils.IsFinite(datumLoss), "Data contain bad values.");
return(weight * datumLoss);
}
public override void ProcessRow()
{
float label = 0;
_labelGetter(ref label);
_scoreGetter(ref Score);
if (float.IsNaN(label))
{
NumUnlabeledInstances++;
return;
}
if (IsNaN(ref Score))
{
NumBadScores++;
return;
}
float weight = 1;
if (_weightGetter != null)
{
_weightGetter(ref weight);
if (!FloatUtils.IsFinite(weight))
{
NumBadWeights++;
weight = 1;
}
}
ApplyLossFunction(ref Score, label, ref Loss);
UnweightedCounters.Update(ref Score, label, 1, ref Loss);
if (WeightedCounters != null)
{
WeightedCounters.Update(ref Score, label, weight, ref Loss);
}
}
public void Save(ModelSaveContext ctx)
{
Contracts.AssertValue(ctx);
// *** Binary format ***
// int: Dimension
// int: Rank
// for i=0,..,Rank-1:
// float[]: the i'th eigenvector
// int: the size of MeanProjected (0 if it is null)
// float[]: MeanProjected
Contracts.Assert(0 < Rank && Rank <= Dimension);
ctx.Writer.Write(Dimension);
ctx.Writer.Write(Rank);
for (int i = 0; i < Rank; i++)
{
Contracts.Assert(FloatUtils.IsFinite(Eigenvectors[i]));
ctx.Writer.WriteSinglesNoCount(Eigenvectors[i].AsSpan(0, Dimension));
}
Contracts.Assert(MeanProjected == null || (MeanProjected.Length == Rank && FloatUtils.IsFinite(MeanProjected)));
ctx.Writer.WriteSingleArray(MeanProjected);
}
/// <summary>
/// Finds approximate minimum of the function
/// </summary>
/// <param name="function">Function to minimize</param>
/// <param name="initial">Initial point</param>
/// <param name="result">Approximate minimum</param>
public void Minimize(DifferentiableFunction function, ref VBuffer <Float> initial, ref VBuffer <Float> result)
{
Contracts.Check(FloatUtils.IsFinite(initial.Values, initial.Count), "The initial vector contains NaNs or infinite values.");
LineFunc lineFunc = new LineFunc(function, ref initial, UseCG);
VBuffer <Float> prev = default(VBuffer <Float>);
initial.CopyTo(ref prev);
for (int n = 0; _maxSteps == 0 || n < _maxSteps; ++n)
{
Float step = LineSearch.Minimize(lineFunc.Eval, lineFunc.Value, lineFunc.Deriv);
var newPoint = lineFunc.NewPoint;
bool terminateNow = n > 0 && TerminateTester.ShouldTerminate(ref newPoint, ref prev);
if (terminateNow || Terminate(ref newPoint))
{
break;
}
newPoint.CopyTo(ref prev);
lineFunc.ChangeDir();
}
lineFunc.NewPoint.CopyTo(ref result);
}
public void Aggregate(double diff, int line, int col)
{
if (diff == 0)
{
return;
}
if (!FloatUtils.IsFinite(diff))
{
InfCount++;
return;
}
if (DiffMax < diff)
{
DiffMax = diff;
LineMax = line;
ColMax = col;
}
DiffTot += diff;
DiffCount++;
}
/// <summary>
/// Samples new hyperparameters for the trainer, and sets them.
/// Returns true if success (new hyperparameters were suggested and set). Else, returns false.
/// </summary>
private static bool SampleHyperparameters(MLContext context, SuggestedTrainer trainer,
IEnumerable <SuggestedPipelineRunDetail> history, bool isMaximizingMetric, IChannel logger)
{
try
{
var sps = ConvertToValueGenerators(trainer.SweepParams);
var sweeper = new SmacSweeper(context,
new SmacSweeper.Arguments
{
SweptParameters = sps
});
IEnumerable <SuggestedPipelineRunDetail> historyToUse = history
.Where(r => r.RunSucceeded && r.Pipeline.Trainer.TrainerName == trainer.TrainerName &&
r.Pipeline.Trainer.HyperParamSet != null &&
r.Pipeline.Trainer.HyperParamSet.Any() &&
FloatUtils.IsFinite(r.Score));
// get new set of hyperparameter values
var proposedParamSet = sweeper.ProposeSweeps(1, historyToUse.Select(h => h.ToRunResult(isMaximizingMetric))).FirstOrDefault();
if (!proposedParamSet.Any())
{
return(false);
}
// associate proposed parameter set with trainer, so that smart hyperparameter
// sweepers (like KDO) can map them back.
trainer.SetHyperparamValues(proposedParamSet);
return(true);
}
catch (Exception ex)
{
logger.Error($"SampleHyperparameters failed with exception: {ex}");
throw;
}
}
protected override TModel TrainModelCore(TrainContext context)
{
Host.CheckValue(context, nameof(context));
var initPredictor = context.InitialPredictor;
var initLinearPred = initPredictor as LinearPredictor ?? (initPredictor as CalibratedPredictorBase)?.SubPredictor as LinearPredictor;
Host.CheckParam(initPredictor == null || initLinearPred != null, nameof(context), "Not a linear predictor.");
var data = context.TrainingSet;
data.CheckFeatureFloatVector(out int numFeatures);
CheckLabel(data);
using (var ch = Host.Start("Training"))
{
InitCore(ch, numFeatures, initLinearPred);
// InitCore should set the number of features field.
Contracts.Assert(NumFeatures > 0);
TrainCore(ch, data);
if (NumBad > 0)
{
ch.Warning(
"Skipped {0} instances with missing features during training (over {1} iterations; {2} inst/iter)",
NumBad, Args.NumIterations, NumBad / Args.NumIterations);
}
Contracts.Assert(WeightsScale == 1);
Float maxNorm = Math.Max(VectorUtils.MaxNorm(ref Weights), Math.Abs(Bias));
Contracts.Check(FloatUtils.IsFinite(maxNorm),
"The weights/bias contain invalid values (NaN or Infinite). Potential causes: high learning rates, no normalization, high initial weights, etc.");
ch.Done();
}
return(CreatePredictor());
}
/// <summary>
/// Initialize predictor from a binary file.
/// </summary>
/// <param name="ctx">The load context</param>
/// <param name="env">The host environment</param>
private KMeansModelParameters(IHostEnvironment env, ModelLoadContext ctx)
: base(env, LoaderSignature, ctx)
{
// *** Binary format ***
// int: k, number of clusters
// int: dimensionality, length of the centroid vectors
// for each cluster, then:
// int: count of this centroid vector (sparse iff count < dimensionality)
// int[count]: only present if sparse, in order indices
// Float[count]: centroid vector values
_k = ctx.Reader.ReadInt32();
Host.CheckDecode(_k > 0);
_dimensionality = ctx.Reader.ReadInt32();
Host.CheckDecode(_dimensionality > 0);
_centroidL2s = new Float[_k];
_centroids = new VBuffer <Float> [_k];
for (int i = 0; i < _k; i++)
{
// Prior to allowing sparse vectors, count was not written and was implicitly
// always equal to dimensionality, and no indices were written either.
int count = ctx.Header.ModelVerWritten >= 0x00010002 ? ctx.Reader.ReadInt32() : _dimensionality;
Host.CheckDecode(0 <= count && count <= _dimensionality);
var indices = count < _dimensionality?ctx.Reader.ReadIntArray(count) : null;
var values = ctx.Reader.ReadFloatArray(count);
Host.CheckDecode(FloatUtils.IsFinite(values));
_centroids[i] = new VBuffer <Float>(_dimensionality, count, values, indices);
}
WarnOnOldNormalizer(ctx, GetType(), Host);
InitPredictor();
_inputType = new VectorType(NumberType.Float, _dimensionality);
_outputType = new VectorType(NumberType.Float, _k);
}
public void GetFeatures(int iCol, int iSlot, Random rand, long key, Span <float> features)
{
_host.Assert(features.Length == NumFeatures);
// get counts from count table in the first _labelBinCount indices.
var countsBuffer = features.Slice(0, _labelBinCount);
var countTable = _countTables[iCol, iSlot];
countTable.GetCounts(key, countsBuffer);
// check if it's garbage and replace with garbage counts if true
float sum = 0;
foreach (var feat in countsBuffer)
{
sum += feat;
}
bool isGarbage = sum < countTable.GarbageThreshold;
if (isGarbage)
{
int i = 0;
foreach (var count in countTable.GarbageCounts)
{
countsBuffer[i++] = count;
}
}
sum = AddLaplacianNoisePerLabel(iCol, rand, countsBuffer);
// add log odds in the next _logOddsCount indices.
GenerateLogOdds(iCol, countTable, countsBuffer, features.Slice(_labelBinCount, _logOddsCount), sum);
_host.Assert(FloatUtils.IsFinite(features));
// Add the last feature: an indicator for isGarbage.
features[NumFeatures - 1] = isGarbage ? 1 : 0;
}
protected sealed override TModel TrainModelCore(TrainContext context)
{
Host.CheckValue(context, nameof(context));
var initPredictor = context.InitialPredictor;
var initLinearPred = initPredictor as LinearPredictor ?? (initPredictor as CalibratedPredictorBase)?.SubPredictor as LinearPredictor;
Host.CheckParam(initPredictor == null || initLinearPred != null, nameof(context), "Not a linear predictor.");
var data = context.TrainingSet;
data.CheckFeatureFloatVector(out int numFeatures);
CheckLabels(data);
using (var ch = Host.Start("Training"))
{
var state = MakeState(ch, numFeatures, initLinearPred);
TrainCore(ch, data, state);
ch.Assert(state.WeightsScale == 1);
Float maxNorm = Math.Max(VectorUtils.MaxNorm(ref state.Weights), Math.Abs(state.Bias));
ch.Check(FloatUtils.IsFinite(maxNorm),
"The weights/bias contain invalid values (NaN or Infinite). Potential causes: high learning rates, no normalization, high initial weights, etc.");
return(state.CreatePredictor());
}
}
internal OlsLinearRegressionPredictor(IHostEnvironment env, ref VBuffer <Float> weights, Float bias,
Double[] standardErrors, Double[] tValues, Double[] pValues, Double rSquared, Double rSquaredAdjusted)
: base(env, RegistrationName, ref weights, bias)
{
Contracts.AssertValueOrNull(standardErrors);
Contracts.AssertValueOrNull(tValues);
Contracts.AssertValueOrNull(pValues);
// If r-squared is NaN then the other statistics must be null, however, if r-rsquared is not NaN,
// then the statistics may be null if creation of statistics was suppressed.
Contracts.Assert(!Double.IsNaN(rSquaredAdjusted) || standardErrors == null);
// Nullity or not must be consistent between the statistics.
Contracts.Assert((standardErrors == null) == (tValues == null) && (tValues == null) == (pValues == null));
Contracts.Assert(0 <= rSquared & rSquared <= 1);
Contracts.Assert(Double.IsNaN(rSquaredAdjusted) | (0 <= rSquaredAdjusted & rSquaredAdjusted <= 1));
if (standardErrors != null)
{
// If not null, the input arrays must have one value for each parameter.
Contracts.Assert(Utils.Size(standardErrors) == weights.Length + 1);
Contracts.Assert(Utils.Size(tValues) == weights.Length + 1);
Contracts.Assert(Utils.Size(pValues) == weights.Length + 1);
#if DEBUG
for (int i = 0; i <= weights.Length; ++i)
{
Contracts.Assert(FloatUtils.IsFinite(standardErrors[i]));
Contracts.Assert(FloatUtils.IsFinite(tValues[i]));
Contracts.Assert(FloatUtils.IsFinite(pValues[i]));
}
#endif
}
_standardErrors = standardErrors;
_tValues = tValues;
_pValues = pValues;
_rSquared = rSquared;
_rSquaredAdjusted = rSquaredAdjusted;
}
private static FloatSphere GetShadowSphere(
Float4x4 ndcToWorldMat,
Float4x4 worldToLightMat,
float shadowDistance)
{
//Frustum of the camera that will be covered by the shadow map in NDC space
//Note: this covers the entire screen but only to a certain depth
FloatBox shadowNDC = new FloatBox(
min: (-1f, -1f, 0f),
max: (1f, 1f, DepthUtils.LinearToDepth(
shadowDistance,
Camera.NEAR_CLIP_DISTANCE,
Camera.FAR_CLIP_DISTANCE)));
//Gather points of the frustum
Span <Float3> points = stackalloc Float3[8];
shadowNDC.GetPoints(points);
//Transform all the points to lightspace (ndc -> world -> lightspace)
Float3 center = Float3.Zero;
for (int i = 0; i < points.Length; i++)
{
points[i] = (worldToLightMat * ndcToWorldMat).TransformPoint(points[i]);
center = i == 0 ? points[i] : (center + points[i]);
}
center /= points.Length;
//The the longest diagonal of the frustum and base our sphere on that
float squareDiag1 = (points[0] - points[6]).SquareMagnitude;
float squareDiag2 = (points[2] - points[4]).SquareMagnitude;
float radius = FloatUtils.SquareRoot(FloatUtils.Max(squareDiag1, squareDiag2)) * .5f;
return(new FloatSphere(center, radius));
}
public IPredictor Calibrate(IChannel ch, IDataView data, ICalibratorTrainer caliTrainer, int maxRows)
{
Host.CheckValue(ch, nameof(ch));
ch.CheckValue(data, nameof(data));
ch.CheckValue(caliTrainer, nameof(caliTrainer));
if (caliTrainer.NeedsTraining)
{
var bound = new Bound(this, new RoleMappedSchema(data.Schema));
using (var curs = data.GetRowCursor(col => true))
{
var scoreGetter = (ValueGetter <Single>)bound.CreateScoreGetter(curs, col => true, out Action disposer);
// We assume that we can use the label column of the first predictor, since if the labels are not identical
// then the whole model is garbage anyway.
var labelGetter = bound.GetLabelGetter(curs, 0, out Action disp);
disposer += disp;
var weightGetter = bound.GetWeightGetter(curs, 0, out disp);
disposer += disp;
try
{
int num = 0;
while (curs.MoveNext())
{
Single label = 0;
labelGetter(ref label);
if (!FloatUtils.IsFinite(label))
{
continue;
}
Single score = 0;
scoreGetter(ref score);
if (!FloatUtils.IsFinite(score))
{
continue;
}
Single weight = 0;
weightGetter(ref weight);
if (!FloatUtils.IsFinite(weight))
{
continue;
}
caliTrainer.ProcessTrainingExample(score, label > 0, weight);
if (maxRows > 0 && ++num >= maxRows)
{
break;
}
}
}
finally
{
disposer?.Invoke();
}
}
}
var calibrator = caliTrainer.FinishTraining(ch);
return(CalibratorUtils.CreateCalibratedPredictor(Host, this, calibrator));
}
private OlsLinearRegressionPredictor TrainCore(IChannel ch, FloatLabelCursor.Factory cursorFactory, int featureCount)
{
Host.AssertValue(ch);
ch.AssertValue(cursorFactory);
int m = featureCount + 1;
// Check for memory conditions first.
if ((long)m * (m + 1) / 2 > int.MaxValue)
{
throw ch.Except("Cannot hold covariance matrix in memory with {0} features", m - 1);
}
// Track the number of examples.
long n = 0;
// Since we are accumulating over many values, we use Double even for the single precision build.
var xty = new Double[m];
// The layout of this algorithm is a packed row-major lower triangular matrix.
var xtx = new Double[m * (m + 1) / 2];
// Build X'X (lower triangular) and X'y incrementally (X'X+=X'X_i; X'y+=X'y_i):
using (var cursor = cursorFactory.Create())
{
while (cursor.MoveNext())
{
var yi = cursor.Label;
// Increment first element of X'y
xty[0] += yi;
// Increment first element of lower triangular X'X
xtx[0] += 1;
var values = cursor.Features.GetValues();
if (cursor.Features.IsDense)
{
int ioff = 1;
ch.Assert(values.Length + 1 == m);
// Increment rest of first column of lower triangular X'X
for (int i = 1; i < m; i++)
{
ch.Assert(ioff == i * (i + 1) / 2);
var val = values[i - 1];
// Add the implicit first bias term to X'X
xtx[ioff++] += val;
// Add the remainder of X'X
for (int j = 0; j < i; j++)
{
xtx[ioff++] += val * values[j];
}
// X'y
xty[i] += val * yi;
}
ch.Assert(ioff == xtx.Length);
}
else
{
var fIndices = cursor.Features.GetIndices();
for (int ii = 0; ii < values.Length; ++ii)
{
int i = fIndices[ii] + 1;
int ioff = i * (i + 1) / 2;
var val = values[ii];
// Add the implicit first bias term to X'X
xtx[ioff++] += val;
// Add the remainder of X'X
for (int jj = 0; jj <= ii; jj++)
{
xtx[ioff + fIndices[jj]] += val * values[jj];
}
// X'y
xty[i] += val * yi;
}
}
n++;
}
ch.Check(n > 0, "No training examples in dataset.");
if (cursor.BadFeaturesRowCount > 0)
{
ch.Warning("Skipped {0} instances with missing features/label during training", cursor.SkippedRowCount);
}
if (_l2Weight > 0)
{
// Skip the bias term for regularization, in the ridge regression case.
// So start at [1,1] instead of [0,0].
// REVIEW: There are two ways to view this, firstly, it is more
// user friendly ot make this scaling factor behave similarly regardless
// of data size, so that if you have the same parameters, you get the same
// model if you feed in your data than if you duplicate your data 10 times.
// This is what I have now. The alternate point of view is to view this
// L2 regularization parameter as providing some sort of prior, in which
// case duplication 10 times should in fact be treated differently! (That
// is, we should not multiply by n below.) Both interpretations seem
// correct, in their way.
Double squared = _l2Weight * _l2Weight * n;
int ioff = 0;
for (int i = 1; i < m; ++i)
{
xtx[ioff += i + 1] += squared;
}
ch.Assert(ioff == xtx.Length - 1);
}
}
if (!(_l2Weight > 0) && n < m)
{
throw ch.Except("Ordinary least squares requires more examples than parameters. There are {0} parameters, but {1} examples. To enable training, use a positive L2 weight so this behaves as ridge regression.", m, n);
}
Double yMean = n == 0 ? 0 : xty[0] / n;
ch.Info("Trainer solving for {0} parameters across {1} examples", m, n);
// Cholesky Decomposition of X'X into LL'
try
{
Mkl.Pptrf(Mkl.Layout.RowMajor, Mkl.UpLo.Lo, m, xtx);
}
catch (DllNotFoundException)
{
// REVIEW: Is there no better way?
throw ch.ExceptNotSupp("The MKL library (libMklImports) or one of its dependencies is missing.");
}
// Solve for beta in (LL')beta = X'y:
Mkl.Pptrs(Mkl.Layout.RowMajor, Mkl.UpLo.Lo, m, 1, xtx, xty, 1);
// Note that the solver overwrote xty so it contains the solution. To be more clear,
// we effectively change its name (through reassignment) so we don't get confused that
// this is somehow xty in the remaining calculation.
var beta = xty;
xty = null;
// Check that the solution is valid.
for (int i = 0; i < beta.Length; ++i)
{
ch.Check(FloatUtils.IsFinite(beta[i]), "Non-finite values detected in OLS solution");
}
var weights = VBufferUtils.CreateDense <float>(beta.Length - 1);
for (int i = 1; i < beta.Length; ++i)
{
weights.Values[i - 1] = (float)beta[i];
}
var bias = (float)beta[0];
if (!(_l2Weight > 0) && m == n)
{
// We would expect the solution to the problem to be exact in this case.
ch.Info("Number of examples equals number of parameters, solution is exact but no statistics can be derived");
return(new OlsLinearRegressionPredictor(Host, in weights, bias, null, null, null, 1, float.NaN));
}
Double rss = 0; // residual sum of squares
Double tss = 0; // total sum of squares
using (var cursor = cursorFactory.Create())
{
var lrPredictor = new LinearRegressionPredictor(Host, in weights, bias);
var lrMap = lrPredictor.GetMapper <VBuffer <float>, float>();
float yh = default;
while (cursor.MoveNext())
{
var features = cursor.Features;
lrMap(in features, ref yh);
var e = cursor.Label - yh;
rss += e * e;
var ydm = cursor.Label - yMean;
tss += ydm * ydm;
}
}
var rSquared = ProbClamp(1 - (rss / tss));
// R^2 adjusted differs from the normal formula on account of the bias term, by Said's reckoning.
double rSquaredAdjusted;
if (n > m)
{
rSquaredAdjusted = ProbClamp(1 - (1 - rSquared) * (n - 1) / (n - m));
ch.Info("Coefficient of determination R2 = {0:g}, or {1:g} (adjusted)",
rSquared, rSquaredAdjusted);
}
else
{
rSquaredAdjusted = Double.NaN;
}
// The per parameter significance is compute intensive and may not be required for all practitioners.
// Also we can't estimate it, unless we can estimate the variance, which requires more examples than
// parameters.
if (!_perParameterSignificance || m >= n)
{
return(new OlsLinearRegressionPredictor(Host, in weights, bias, null, null, null, rSquared, rSquaredAdjusted));
}
ch.Assert(!Double.IsNaN(rSquaredAdjusted));
var standardErrors = new Double[m];
var tValues = new Double[m];
var pValues = new Double[m];
// Invert X'X:
Mkl.Pptri(Mkl.Layout.RowMajor, Mkl.UpLo.Lo, m, xtx);
var s2 = rss / (n - m); // estimate of variance of y
for (int i = 0; i < m; i++)
{
// Initialize with inverse Hessian.
standardErrors[i] = (Single)xtx[i * (i + 1) / 2 + i];
}
if (_l2Weight > 0)
{
// Iterate through all entries of inverse Hessian to make adjustment to variance.
int ioffset = 1;
float reg = _l2Weight * _l2Weight * n;
for (int iRow = 1; iRow < m; iRow++)
{
for (int iCol = 0; iCol <= iRow; iCol++)
{
var entry = (Single)xtx[ioffset];
var adjustment = -reg * entry * entry;
standardErrors[iRow] -= adjustment;
if (0 < iCol && iCol < iRow)
{
standardErrors[iCol] -= adjustment;
}
ioffset++;
}
}
Contracts.Assert(ioffset == xtx.Length);
}
for (int i = 0; i < m; i++)
{
// sqrt of diagonal entries of s2 * inverse(X'X + reg * I) * X'X * inverse(X'X + reg * I).
standardErrors[i] = Math.Sqrt(s2 * standardErrors[i]);
ch.Check(FloatUtils.IsFinite(standardErrors[i]), "Non-finite standard error detected from OLS solution");
tValues[i] = beta[i] / standardErrors[i];
pValues[i] = (float)MathUtils.TStatisticToPValue(tValues[i], n - m);
ch.Check(0 <= pValues[i] && pValues[i] <= 1, "p-Value calculated outside expected [0,1] range");
}
return(new OlsLinearRegressionPredictor(Host, in weights, bias, standardErrors, tValues, pValues, rSquared, rSquaredAdjusted));
}
