internal MatrixFactorizationModelParameters(IHostEnvironment env, SafeTrainingAndModelBuffer buffer, KeyDataViewType matrixColumnIndexType, KeyDataViewType matrixRowIndexType)
{
Contracts.CheckValue(env, nameof(env));
_host = env.Register(RegistrationName);
_host.Assert(matrixColumnIndexType.RawType == typeof(uint));
_host.Assert(matrixRowIndexType.RawType == typeof(uint));
_host.CheckValue(buffer, nameof(buffer));
_host.CheckValue(matrixColumnIndexType, nameof(matrixColumnIndexType));
_host.CheckValue(matrixRowIndexType, nameof(matrixRowIndexType));
buffer.Get(out NumberOfRows, out NumberOfColumns, out ApproximationRank, out var leftFactorMatrix, out var rightFactorMatrix);
_leftFactorMatrix = leftFactorMatrix;
_rightFactorMatrix = rightFactorMatrix;
_host.Assert(NumberOfColumns == matrixColumnIndexType.GetCountAsInt32(_host));
_host.Assert(NumberOfRows == matrixRowIndexType.GetCountAsInt32(_host));
_host.Assert(_leftFactorMatrix.Length == NumberOfRows * ApproximationRank);
_host.Assert(_rightFactorMatrix.Length == ApproximationRank * NumberOfColumns);
MatrixColumnIndexType = matrixColumnIndexType;
MatrixRowIndexType = matrixRowIndexType;
}
private static IDataView AppendFloatMapper <TInput>(IHostEnvironment env, IChannel ch, IDataView input,
string col, KeyDataViewType type, int seed)
{
// Any key is convertible to ulong, so rather than add special case handling for all possible
// key-types we just upfront convert it to the most general type (ulong) and work from there.
KeyDataViewType dstType = new KeyDataViewType(typeof(ulong), type.Count);
bool identity;
var converter = Conversions.Instance.GetStandardConversion <TInput, ulong>(type, dstType, out identity);
var isNa = Conversions.Instance.GetIsNAPredicate <TInput>(type);
ValueMapper <TInput, Single> mapper;
if (seed == 0)
{
mapper =
(in TInput src, ref Single dst) =>
{
//Attention: This method is called from multiple threads.
//Do not move the temp variable outside this method.
//If you do, the variable is shared between the threads and results in a race condition.
ulong temp = 0;
if (isNa(in src))
{
dst = Single.NaN;
return;
}
converter(in src, ref temp);
dst = (Single)temp - 1;
};
}
else
{
ch.Check(type.Count > 0, "Label must be of known cardinality.");
int[] permutation = Utils.GetRandomPermutation(RandomUtils.Create(seed), type.GetCountAsInt32(env));
mapper =
(in TInput src, ref Single dst) =>
{
//Attention: This method is called from multiple threads.
//Do not move the temp variable outside this method.
//If you do, the variable is shared between the threads and results in a race condition.
ulong temp = 0;
if (isNa(in src))
{
dst = Single.NaN;
return;
}
converter(in src, ref temp);
dst = (Single)permutation[(int)(temp - 1)];
};
}
return(LambdaColumnMapper.Create(env, "Key to Float Mapper", input, col, col, type, NumberDataViewType.Single, mapper));
}