/// <summary>
/// compute vector dot product
/// </summary>
/// <param name="otherVector"></param>
/// <returns></returns>
public float DotProduct(SparseVec otherVector)
{
if (otherVector == null)
{
throw new ArgumentNullException("otherVector");
}
if (otherVector.Dim != Dim)
{
string expMsg = string.Format("different dimensions vec1={0} vec2={1}", this.ToString(), otherVector.ToString());
throw new ArgumentException(expMsg, "otherVector");
}
float result = 0;
if (Count < 1)
{
return(0.0f);
}
if (otherVector.Count < 1)
{
return(0.0f);
}
int i1 = 0;
int i2 = 0;
while (i1 < this.Count && i2 < otherVector.Count)
{
int index1 = Indices[i1];
int index2 = otherVector.Indices[i2];
if (index1 == index2)
{
float mul = Values[i1] * otherVector.Values[i2];
result += mul;
i1++; i2++;
}
else if (index1 < index2)
{
i1++;
}
else
{
i2++;
}
}
return(result);
}
public SparseVec Subtract(SparseVec otherVec)
{
int v1 = 0;
int v2 = 0;
List <float> vals = new List <float>();
List <int> idx = new List <int>();
while (v1 < this.Count || v2 < otherVec.Count)
{
int v1Idx = this.Indices[v1];
int v2Idx = otherVec.Indices[v2];
if (v1Idx == v2Idx)
{
float sub = this.Values[v1] - otherVec.Values[v2];
if (sub != 0)
{
vals.Add(sub);
idx.Add(v1Idx);
}
v1++; v2++;
}
else if (v1Idx < v2Idx)
{
// this.Values[v1] - 0.0
vals.Add(this.Values[v1]);
idx.Add(v1Idx);
v1++;
}
else
{
vals.Add(0.0f - otherVec.Values[v2]);
idx.Add(v2Idx);
v2++;
}
}
SparseVec sp = new SparseVec(this.Dim, idx, vals);
return(sp);
}
