public void RemoveATriplet(int row, int col)
{
Triplet curr = this.GetTriplet(row, col);
if (curr != null)
{
triplets.Remove(curr);
rowTriplets[row].Remove(curr);
colTriplets[col].Remove(curr);
}
}
static public SparseMatrix operator *(SparseMatrix mat1, SparseMatrix mat2)
{
if (mat1 == null || mat2 == null)
{
return(null);
}
int m = mat1.NRow, n = mat2.NCol;
if (mat1.NCol != mat2.NRow)
{
Console.WriteLine("Dimension not matched.");
return(null);
}
SparseMatrix mat = new SparseMatrix(m, n);
List <Triplet> newTriplets = new List <Triplet>();
for (int r = 0; r < m; ++r)
{
List <Triplet> row1 = mat1.GetRowTriplets(r);
for (int c = 0; c < n; ++c)
{
List <Triplet> col2 = mat2.GetColumnTriplets(c);
double sum = 0.0;
int n1 = 0, n2 = 0;
while (n1 < row1.Count && n2 < col2.Count)
{
int c1 = row1[n1].col;
int r2 = col2[n2].row;
if (c1 < r2)
{
++n1;
}
else if (r2 < c1)
{
++n2;
}
else
{
sum += row1[n1].value * col2[n2].value;
++n1;
++n2;
}
} //while
if (Math.Abs(sum) > 1e-6)
{
Triplet triplet = new Triplet(r, c, sum);
newTriplets.Add(triplet);
}
}
} //for-each-row
mat = new SparseMatrix(newTriplets);
return(mat);
}
public void AddTriplet(Triplet triplet)
{
if (triplets == null) // do not initialize here, as row/col is unknown
{
throw new NullReferenceException();
}
if (triplet.row < 0 || triplet.row >= nRows || triplet.col < 0 || triplet.col >= nCols)
{
throw new IndexOutOfRangeException();
}
triplets.Add(triplet);
rowTriplets[triplet.row].Add(triplet);
rowTriplets[triplet.row].Sort(new Triplet.TripletRowComparer());
colTriplets[triplet.col].Add(triplet);
colTriplets[triplet.col].Sort(new Triplet.TripletColumnComparer());
}
public void AddTriplet(int row, int col, double value)
{
Triplet triplet = new Triplet(row, col, value);
Triplet curr = this.GetTriplet(row, col);
if (curr == null)
{
this.AddTriplet(triplet);
}
else
{
curr.value = value;
}
//if (value == 0)
//{
// // remove
// triplets.Remove(triplet);
// rowTriplets[row].Remove(triplet);
// colTriplets[col].Remove(triplet);
//}
}
// operators
static public SparseMatrix operator +(SparseMatrix mat1, SparseMatrix mat2)
{
if (mat1 == null || mat2 == null)
{
return(null);
}
int m = mat1.NRow, n = mat1.NCol;
if (m != mat2.NRow || n != mat2.NCol)
{
Console.WriteLine("Dimension not matched.");
return(null);
}
SparseMatrix mat = new SparseMatrix(m, n);
List <Triplet> newTriplets = new List <Triplet>();
for (int r = 0; r < m; ++r)
{
List <Triplet> trips = new List <Triplet>();
List <Triplet> row1 = mat1.GetRowTriplets(r);
List <Triplet> row2 = mat2.GetRowTriplets(r);
int c1 = 0, c2 = 0;
while (c1 < row1.Count && c2 < row2.Count)
{
Triplet t1 = null, t2 = null;
t1 = row1[c1];
t2 = row2[c2];
if (t1 != null && t2 != null)
{
if (t1.col < t2.col)
{
trips.Add(new Triplet(t1));
++c1;
}
else if (t2.col < t1.col)
{
trips.Add(new Triplet(t2));
++c2;
}
else
{
trips.Add(new Triplet(r, c1, t1.value + t2.value));
++c1;
++c2;
}
}
} //while
while (c1 < row1.Count)
{
trips.Add(new Triplet(row1[c1]));
++c1;
}
while (c2 < row2.Count)
{
trips.Add(new Triplet(row2[c2]));
++c2;
}
newTriplets.AddRange(trips);
} //for-each-row
mat = new SparseMatrix(newTriplets, m, n);
return(mat);
}
public Triplet(Triplet t)
{
this.row = t.row;
this.col = t.col;
this.value = t.value;
}
