private static void FillValues(IExceptionContext ectx, ref VBuffer <Float> src, ref VBuffer <Float> dst, Float divisor, Float scale, Float offset = 0)
{
int count = src.Count;
int length = src.Length;
ectx.Assert(Utils.Size(src.Values) >= count);
ectx.Assert(divisor >= 0);
if (count == 0)
{
dst = new VBuffer <Float>(length, 0, dst.Values, dst.Indices);
return;
}
ectx.Assert(count > 0);
ectx.Assert(length > 0);
Float normScale = scale;
if (divisor > 0)
{
normScale /= divisor;
}
// Don't normalize small values.
if (normScale < MinScale)
{
normScale = 1;
}
if (offset == 0)
{
var dstValues = dst.Values;
if (Utils.Size(dstValues) < count)
{
dstValues = new Float[count];
}
var dstIndices = dst.Indices;
if (!src.IsDense)
{
if (Utils.Size(dstIndices) < count)
{
dstIndices = new int[count];
}
Array.Copy(src.Indices, dstIndices, count);
}
SseUtils.Scale(normScale, src.Values, dstValues, count);
dst = new VBuffer <Float>(length, count, dstValues, dstIndices);
return;
}
// Subtracting the mean requires a dense representation.
src.CopyToDense(ref dst);
if (normScale != 1)
{
SseUtils.ScaleAdd(normScale, -offset, dst.Values, length);
}
else
{
SseUtils.Add(-offset, dst.Values, length);
}
}
public static void ScaleAdd(float a, float b, float[] dst, int count) => SseUtils.ScaleAdd(a, b, dst, count);