/// <summary>
/// Outer product of this and another vector.
/// </summary>
/// <param name="v">The vector to operate on.</param>
/// <returns>
/// Matrix M[i,j] = this[i] * v[j].
/// </returns>
public Matrix<float> OuterProduct(SparseVector v)
{
return OuterProduct(this, v);
}
/// <summary>
/// Converts the string representation of a real sparse vector to float-precision sparse vector equivalent.
/// A return value indicates whether the conversion succeeded or failed.
/// </summary>
/// <param name="value">
/// A string containing a real vector to convert.
/// </param>
/// <param name="result">
/// The parsed value.
/// </param>
/// <returns>
/// If the conversion succeeds, the result will contain a complex number equivalent to value.
/// Otherwise the result will be <c>null</c>.
/// </returns>
public static bool TryParse(string value, out SparseVector result)
{
return TryParse(value, null, out result);
}
/// <summary>
/// Converts the string representation of a real sparse vector to float-precision sparse vector equivalent.
/// A return value indicates whether the conversion succeeded or failed.
/// </summary>
/// <param name="value">
/// A string containing a real vector to convert.
/// </param>
/// <param name="formatProvider">
/// An <see cref="IFormatProvider"/> that supplies culture-specific formatting information about value.
/// </param>
/// <param name="result">
/// The parsed value.
/// </param>
/// <returns>
/// If the conversion succeeds, the result will contain a complex number equivalent to value.
/// Otherwise the result will be <c>null</c>.
/// </returns>
public static bool TryParse(string value, IFormatProvider formatProvider, out SparseVector result)
{
bool ret;
try
{
result = Parse(value, formatProvider);
ret = true;
}
catch (ArgumentNullException)
{
result = null;
ret = false;
}
catch (FormatException)
{
result = null;
ret = false;
}
return ret;
}
/// <summary>
/// Creates a vector containing specified elements.
/// </summary>
/// <param name="index">The first element to begin copying from.</param>
/// <param name="length">The number of elements to copy.</param>
/// <returns>A vector containing a copy of the specified elements.</returns>
/// <exception cref="ArgumentOutOfRangeException"><list><item>If <paramref name="index"/> is not positive or
/// greater than or equal to the size of the vector.</item>
/// <item>If <paramref name="index"/> + <paramref name="length"/> is greater than or equal to the size of the vector.</item>
/// </list></exception>
/// <exception cref="ArgumentException">If <paramref name="length"/> is not positive.</exception>
public override Vector<float> SubVector(int index, int length)
{
if (index < 0 || index >= Count)
{
throw new ArgumentOutOfRangeException("index");
}
if (length <= 0)
{
throw new ArgumentOutOfRangeException("length");
}
if (index + length > Count)
{
throw new ArgumentOutOfRangeException("length");
}
var result = new SparseVector(length);
for (var i = index; i < index + length; i++)
{
result[i - index] = this[i];
}
return result;
}
/// <summary>
/// Outer product of two vectors
/// </summary>
/// <param name="u">First vector</param>
/// <param name="v">Second vector</param>
/// <returns>Matrix M[i,j] = u[i]*v[j] </returns>
/// <exception cref="ArgumentNullException">If the u vector is <see langword="null" />.</exception>
/// <exception cref="ArgumentNullException">If the v vector is <see langword="null" />.</exception>
public static Matrix<float> OuterProduct(SparseVector u, SparseVector v)
{
if (u == null)
{
throw new ArgumentNullException("u");
}
if (v == null)
{
throw new ArgumentNullException("v");
}
var matrix = new SparseMatrix(u.Count, v.Count);
for (var i = 0; i < u._storage.ValueCount; i++)
{
for (var j = 0; j < v._storage.ValueCount; j++)
{
if (u._storage.Indices[i] == v._storage.Indices[j])
{
matrix.At(i, j, u._storage.Values[i] * v._storage.Values[j]);
}
}
}
return matrix;
}
/// <summary>
/// Multiplies a scalar to each element of the vector.
/// </summary>
/// <param name="scalar">The scalar to multiply.</param>
/// <returns>A new vector that is the multiplication of the vector and the scalar.</returns>
public override Vector<float> Multiply(float scalar)
{
if (scalar == 1.0f)
{
return Clone();
}
if (scalar == 0f)
{
return new SparseVector(Count);
}
var copy = new SparseVector(this);
Control.LinearAlgebraProvider.ScaleArray(scalar, copy._storage.Values, copy._storage.Values);
return copy;
}
/// <summary>
/// Converts the string representation of a real sparse vector to float-precision sparse vector equivalent.
/// A return value indicates whether the conversion succeeded or failed.
/// </summary>
/// <param name="value">
/// A string containing a real vector to convert.
/// </param>
/// <param name="result">
/// The parsed value.
/// </param>
/// <returns>
/// If the conversion succeeds, the result will contain a complex number equivalent to value.
/// Otherwise the result will be <c>null</c>.
/// </returns>
public static bool TryParse(string value, out SparseVector result)
{
return(TryParse(value, null, out result));
}
/// <summary>
/// Outer product of this and another vector.
/// </summary>
/// <param name="v">The vector to operate on.</param>
/// <returns>
/// Matrix M[i,j] = this[i] * v[j].
/// </returns>
public Matrix <float> OuterProduct(SparseVector v)
{
return(OuterProduct(this, v));
}
/// <summary>
/// Returns a negated vector.
/// </summary>
/// <returns>The negated vector.</returns>
/// <remarks>Added as an alternative to the unary negation operator.</remarks>
public override Vector<float> Negate()
{
var result = new SparseVector(Count)
{
_nonZeroValues = new float[NonZerosCount],
_nonZeroIndices = new int[NonZerosCount],
NonZerosCount = NonZerosCount
};
if (NonZerosCount != 0)
{
CommonParallel.For(
0,
NonZerosCount,
index => result._nonZeroValues[index] = -_nonZeroValues[index]);
Buffer.BlockCopy(_nonZeroIndices, 0, result._nonZeroIndices, 0, NonZerosCount * Constants.SizeOfInt);
}
return result;
}
/// <summary>
/// Initializes a new instance of the <see cref="SparseVector"/> class by
/// copying the values from another.
/// </summary>
/// <param name="other">
/// The vector to create the new vector from.
/// </param>
public SparseVector(SparseVector other) : this(other.Count)
{
// Lets copy only needed data. Portion of needed data is determined by NonZerosCount value
_nonZeroValues = new float[other.NonZerosCount];
_nonZeroIndices = new int[other.NonZerosCount];
NonZerosCount = other.NonZerosCount;
Buffer.BlockCopy(other._nonZeroValues, 0, _nonZeroValues, 0, other.NonZerosCount * Constants.SizeOfFloat);
Buffer.BlockCopy(other._nonZeroIndices, 0, _nonZeroIndices, 0, other.NonZerosCount * Constants.SizeOfInt);
}
