public static Float DotProduct(Float[] a, ref VBuffer <Float> b)
{
Contracts.Check(Utils.Size(a) == b.Length, "Vectors must have the same dimensionality.");
if (b.Count == 0)
{
return(0);
}
if (b.IsDense)
{
return(SseUtils.DotProductDense(a, b.Values, b.Length));
}
return(SseUtils.DotProductSparse(a, b.Values, b.Indices, b.Count));
}
/// <summary>
/// Computes the dot product of two arrays
/// Where "offset" is considered to be a's zero index
/// </summary>
/// <param name="a">one array</param>
/// <param name="b">the second array (given as a VBuffer)</param>
/// <param name="offset">offset in 'a'</param>
/// <returns>the dot product</returns>
public static Float DotProductWithOffset(ref VBuffer <Float> a, int offset, ref VBuffer <Float> b)
{
Contracts.Check(0 <= offset && offset <= a.Length);
Contracts.Check(b.Length <= a.Length - offset, "VBuffer b must be no longer than a.Length - offset.");
if (a.Count == 0 || b.Count == 0)
{
return(0);
}
if (a.IsDense)
{
if (b.IsDense)
{
return(SseUtils.DotProductDense(a.Values, offset, b.Values, b.Length));
}
return(SseUtils.DotProductSparse(a.Values, offset, b.Values, b.Indices, b.Count));
}
else
{
Float result = 0;
int aMin = Utils.FindIndexSorted(a.Indices, 0, a.Count, offset);
int aLim = Utils.FindIndexSorted(a.Indices, 0, a.Count, offset + b.Length);
if (b.IsDense)
{
for (int iA = aMin; iA < aLim; ++iA)
{
result += a.Values[iA] * b.Values[a.Indices[iA] - offset];
}
return(result);
}
for (int iA = aMin, iB = 0; iA < aLim && iB < b.Count;)
{
int aIndex = a.Indices[iA];
int bIndex = b.Indices[iB];
int comp = (aIndex - offset) - bIndex;
if (comp == 0)
{
result += a.Values[iA++] * b.Values[iB++];
}
else if (comp < 0)
{
iA++;
}
else
{
iB++;
}
}
return(result);
}
}
/// <summary>
/// Computes the dot product of two arrays
/// Where "offset" is considered to be a's zero index
/// </summary>
/// <param name="a">one array</param>
/// <param name="b">the second array (given as a VBuffer)</param>
/// <param name="offset">offset in 'a'</param>
/// <returns>the dot product</returns>
public static Float DotProductWithOffset(Float[] a, int offset, ref VBuffer <Float> b)
{
Contracts.Check(0 <= offset && offset <= a.Length);
Contracts.Check(b.Length <= a.Length - offset, "VBuffer b must be no longer than a.Length - offset.");
if (b.Count == 0)
{
return(0);
}
if (b.IsDense)
{
return(SseUtils.DotProductDense(a, offset, b.Values, b.Length));
}
return(SseUtils.DotProductSparse(a, offset, b.Values, b.Indices, b.Count));
}
private static Float L2DistSquaredHalfSparse(Float[] valuesA, int lengthA, Float[] valuesB, int[] indicesB, int countB)
{
Contracts.AssertValueOrNull(valuesA);
Contracts.AssertValueOrNull(valuesB);
Contracts.AssertValueOrNull(indicesB);
Contracts.Assert(0 <= lengthA && lengthA <= Utils.Size(valuesA));
Contracts.Assert(0 <= countB && countB <= Utils.Size(indicesB));
Contracts.Assert(countB <= Utils.Size(valuesB));
var normA = SseUtils.SumSq(valuesA, 0, lengthA);
if (countB == 0)
{
return(normA);
}
var normB = SseUtils.SumSq(valuesB, 0, countB);
var dotP = SseUtils.DotProductSparse(valuesA, valuesB, indicesB, countB);
var res = normA + normB - 2 * dotP;
return(res < 0 ? 0 : res);
}
public static Float DotProduct(ref VBuffer <Float> a, ref VBuffer <Float> b)
{
Contracts.Check(a.Length == b.Length, "Vectors must have the same dimensionality.");
if (a.Count == 0 || b.Count == 0)
{
return(0);
}
if (a.IsDense)
{
if (b.IsDense)
{
return(SseUtils.DotProductDense(a.Values, b.Values, a.Length));
}
return(SseUtils.DotProductSparse(a.Values, b.Values, b.Indices, b.Count));
}
if (b.IsDense)
{
return(SseUtils.DotProductSparse(b.Values, a.Values, a.Indices, a.Count));
}
return(DotProductSparse(a.Values, a.Indices, 0, a.Count, b.Values, b.Indices, 0, b.Count, 0));
}
/// <summary>
/// Returns a dot product of dense vector 'a' starting from offset 'aOffset' and sparse vector 'b'
/// with first 'count' valid elements and their corresponding 'indices'.
/// </summary>
private static Float DotProduct(Float[] a, int aOffset, Float[] b, int[] indices, int count)
{
Contracts.Assert(count <= indices.Length);
return(SseUtils.DotProductSparse(a, aOffset, b, indices, count));
}
public static float DotProductSparse(float[] a, int offset, float[] b, int[] indices, int count) => SseUtils.DotProductSparse(a, offset, b, indices, count);
