/// <summary>
/// See <see cref="IVector.AxpyIntoThis(IVectorView, double)"/>.
/// </summary>
public void AxpyIntoThis(IVectorView otherVector, double otherCoefficient)
{
if (otherVector is Vector dense)
{
AxpyIntoThis(dense, otherCoefficient);
}
else
{
Preconditions.CheckVectorDimensions(this, otherVector);
if (otherVector is SparseVector sparse)
{
if (sparse.RawIndices.Length != 0)
{
SparseBlas.Daxpyi(sparse.RawIndices.Length, otherCoefficient, sparse.RawValues,
sparse.RawIndices, 0, data, 0);
}
}
else
{
for (int i = 0; i < Length; ++i)
{
this.data[i] += otherCoefficient * otherVector[i];
}
}
}
}
/// <summary>
/// Performs the matrix-vector multiplication: <paramref name="rhsVector"/> = oper(this) * <paramref name="vector"/>.
/// To multiply this * columnVector, set <paramref name="transposeThis"/> to false.
/// To multiply rowVector * this, set <paramref name="transposeThis"/> to true.
/// The resulting vector will overwrite the entries of <paramref name="rhsVector"/>.
/// </summary>
/// <param name="lhsVector">
/// The vector that will be multiplied by this matrix. It sits on the left hand side of the equation y = oper(A) * x.
/// Constraints: <paramref name="lhsVector"/>.<see cref="IIndexable1D.Length"/>
/// == oper(this).<see cref="IIndexable2D.NumColumns"/>.
/// </param>
/// <param name="rhsVector">
/// The vector that will be overwritten by the result of the multiplication. It sits on the right hand side of the
/// equation y = oper(A) * x. Constraints: <paramref name="lhsVector"/>.<see cref="IIndexable1D.Length"/>
/// == oper(this).<see cref="IIndexable2D.NumRows"/>.
/// </param>
/// <param name="transposeThis">If true, oper(this) = transpose(this). Otherwise oper(this) = this.</param>
/// <exception cref="NonMatchingDimensionsException">
/// Thrown if the <see cref="IIndexable1D.Length"/> of <paramref name="lhsVector"/> or <paramref name="rhsVector"/>
/// violate the described contraints.
/// </exception>
public void MultiplyIntoResult(Vector lhsVector, Vector rhsVector, bool transposeThis = false)
{
if (transposeThis)
{
Preconditions.CheckMultiplicationDimensions(NumRows, lhsVector.Length);
Preconditions.CheckSystemSolutionDimensions(NumColumns, rhsVector.Length);
}
else
{
Preconditions.CheckMultiplicationDimensions(NumColumns, lhsVector.Length);
Preconditions.CheckSystemSolutionDimensions(NumRows, rhsVector.Length);
}
SparseBlas.Dcscgemv(transposeThis, NumRows, NumColumns, values, colOffsets, rowIndices,
lhsVector.RawData, 0, rhsVector.RawData, 0);
}
/// <summary>
/// See <see cref="IVectorView.Axpy(IVectorView, double)"/>.
/// </summary>
public IVector Axpy(IVectorView otherVector, double otherCoefficient)
{
if (otherVector is Vector dense)
{
return(Axpy(dense, otherCoefficient));
}
else if (otherVector is SparseVector sparse)
{
Preconditions.CheckVectorDimensions(this, otherVector);
double[] result = new double[data.Length];
Array.Copy(data, result, data.Length);
SparseBlas.Daxpyi(sparse.RawIndices.Length, otherCoefficient, sparse.RawValues,
sparse.RawIndices, 0, result, 0);
return(Vector.CreateFromArray(result, false));
}
else
{
return(otherVector.LinearCombination(otherCoefficient, this, 1.0)); // To avoid accessing zero entries
}
}
/// <summary>
/// Performs the matrix-matrix multiplication: oper(this) * <paramref name="other"/>.
/// </summary>
/// <param name="other">
/// A matrix such that the <see cref="IIndexable2D.NumRows"/> of <paramref name="other"/> are equal to the
/// <see cref="IIndexable2D.NumColumns"/> of oper(this).
/// </param>
/// <param name="transposeThis">If true, oper(this) = transpose(this). Otherwise oper(this) = this.</param>
/// <exception cref="Exceptions.NonMatchingDimensionsException">
/// Thrown if <paramref name="otherMatrix"/> has different <see cref="IIndexable2D.NumRows"/> than the
/// <see cref="IIndexable2D.NumColumns"/> of oper(this).
/// </exception>
public Matrix MultiplyRight(Matrix other, bool transposeThis)
{
int numRowsResult;
if (transposeThis)
{
Preconditions.CheckMultiplicationDimensions(this.NumRows, other.NumRows);
numRowsResult = this.NumColumns;
}
else
{
Preconditions.CheckMultiplicationDimensions(this.NumColumns, other.NumRows);
numRowsResult = this.NumRows;
}
var result = Matrix.CreateZero(numRowsResult, other.NumColumns);
SparseBlas.Dcscgemm(transposeThis, this.NumRows, other.NumColumns, this.NumColumns, values, colOffsets, rowIndices,
other.RawData, result.RawData);
return(result);
}
/// <summary>
/// See <see cref="IVectorView.DotProduct(IVectorView)"/>.
/// </summary>
public double DotProduct(IVectorView vector)
{
Preconditions.CheckVectorDimensions(this, vector);
if (vector is Vector dense)
{
return(SparseBlas.Ddoti(values.Length, values, indices, 0, dense.RawData, 0));
}
else if ((vector is SparseVector sparse) && HasSameIndexer(sparse))
{
return(Blas.Ddot(values.Length, this.values, 0, 1, sparse.values, 0, 1));
}
double sum = 0;
for (int i = 0; i < values.Length; ++i)
{
sum += values[i] * vector[indices[i]];
}
return(sum);
}
/// <summary>
/// See <see cref="IVectorView.Axpy(IVectorView, double)"/>.
/// </summary>
public IVector Axpy(IVectorView otherVector, double otherCoefficient)
{
Preconditions.CheckVectorDimensions(this, otherVector);
if (otherVector is SparseVector otherSparse) // In case both matrices have the exact same index arrays
{
if (HasSameIndexer(otherSparse))
{
// Do not copy the index arrays, since they are already spread around. TODO: is this a good idea?
double[] result = new double[this.values.Length];
Array.Copy(this.values, result, this.values.Length);
Blas.Daxpy(values.Length, otherCoefficient, otherSparse.values, 0, 1, result, 0, 1);
return(new SparseVector(Length, result, indices));
}
}
else if (otherVector is Vector otherDense)
{
double[] result = otherDense.Scale(otherCoefficient).RawData;
SparseBlas.Daxpyi(this.indices.Length, 1.0, this.values, this.indices, 0, result, 0);
return(Vector.CreateFromArray(result, false));
}
// All entries must be processed. TODO: optimizations may be possible (e.g. only access the nnz in this vector)
return(DenseStrategies.LinearCombination(this, 1.0, otherVector, otherCoefficient));
}
/// <summary>
/// See <see cref="IVector.AxpyIntoThis(IVectorView, double)"/>.
/// </summary>
public void AxpyIntoThis(IVectorView otherVector, double otherCoefficient)
{
if (otherVector is Vector dense)
{
AxpyIntoThis(dense, otherCoefficient);
}
else
{
Preconditions.CheckVectorDimensions(this, otherVector);
if (otherVector is SparseVector sparse)
{
//TODO: should I check whether the sparse vector is all 0, in order to avoid the BLAS call?
SparseBlas.Daxpyi(sparse.RawIndices.Length, otherCoefficient, sparse.RawValues,
sparse.RawIndices, 0, data, 0);
}
else
{
for (int i = 0; i < Length; ++i)
{
this.data[i] += otherCoefficient * otherVector[i];
}
}
}
}
