public ColInfoEx(GcnColumn col, GcnArguments args)
{
SubtractMean = col.SubMean ?? args.SubMean;
NormKind = (col.UseStdDev ?? args.UseStdDev) ? NormalizerKind.StdDev : NormalizerKind.L2Norm;
Scale = col.Scale ?? args.Scale;
Contracts.CheckUserArg(0 < Scale && Scale < Float.PositiveInfinity, nameof(args.Scale), "scale must be a positive finite value");
}
/// <summary>
/// A helper method to create GlobalContrastNormalizer transform for public facing API.
/// </summary>
/// <param name="env">Host Environment.</param>
/// <param name="input">Input <see cref="IDataView"/>. This is the output from previous transform or loader.</param>
/// <param name="name">Name of the output column.</param>
/// <param name="source">Name of the column to be transformed. If this is null '<paramref name="name"/>' will be used.</param>
/// <param name="subMean">Subtract mean from each value before normalizing.</param>
/// <param name="useStdDev">Normalize by standard deviation rather than L2 norm.</param>
/// <param name="scale">Scale features by this value.</param>
public static IDataTransform CreateGlobalContrastNormalizer(IHostEnvironment env,
IDataView input,
string name,
string source = null,
bool subMean = Defaults.GcnSubMean,
bool useStdDev = Defaults.UseStdDev,
Float scale = Defaults.Scale)
{
var args = new GcnArguments()
{
Column = new[] { new GcnColumn()
{
Source = source ?? name,
Name = name
} },
SubMean = subMean,
UseStdDev = useStdDev,
Scale = scale
};
return(new LpNormNormalizerTransform(env, args, input));
}
/// <summary>
/// Public constructor corresponding to SignatureDataTransform.
/// </summary>
public LpNormNormalizerTransform(IHostEnvironment env, GcnArguments args, IDataView input)
: base(env, RegistrationName, env.CheckRef(args, nameof(args)).Column,
input, TestIsFloatVector)
{
Host.AssertNonEmpty(Infos);
Host.Assert(Infos.Length == Utils.Size(args.Column));
_exes = new ColInfoEx[Infos.Length];
for (int i = 0; i < _exes.Length; i++)
{
_exes[i] = new ColInfoEx(args.Column[i], args);
}
// REVIEW: for now check only global (default) values. Move to Bindings/ColInfoEx?
if (!args.SubMean && args.UseStdDev)
{
using (var ch = Host.Start("Argument validation"))
{
ch.Warning("subMean parameter is false while useStd is true. It is advisable to set subMean to true in case useStd is set to true.");
}
}
SetMetadata();
}
