示例#1
0
// Outer calculates the outer product of x and y, and stores the result
// in the receiver. In order to update to an existing matrix, see RankOne.
//  m = x * y'
func (m *Dense) Outer(x, y *Vector) {
	r := x.Len()
	c := y.Len()

	// Copied from reuseAs with use replaced by useZeroed
	// and a final zero of the matrix elements if we pass
	// the shape checks.
	// TODO(kortschak): Factor out into reuseZeroedAs if
	// we find another case that needs it.
	if m.mat.Rows > m.capRows || m.mat.Cols > m.capCols {
		// Panic as a string, not a mat64.Error.
		panic("mat64: caps not correctly set")
	}
	if m.isZero() {
		m.mat = blas64.General{
			Rows:   r,
			Cols:   c,
			Stride: c,
			Data:   useZeroed(m.mat.Data, r*c),
		}
		m.capRows = r
		m.capCols = c
	} else if r != m.mat.Rows || c != m.mat.Cols {
		panic(ErrShape)
	} else {
		for i := 0; i < r; i++ {
			zero(m.mat.Data[i*m.mat.Stride : i*m.mat.Stride+c])
		}
	}

	blas64.Ger(1, x.mat, y.mat, m.mat)
}
示例#2
0
// RankOne performs a rank-one update to the matrix a and stores the result
// in the receiver. If a is zero, see Outer.
//  m = a + alpha * x * y'
func (m *Dense) RankOne(a Matrix, alpha float64, x, y *Vector) {
	ar, ac := a.Dims()
	if x.Len() != ar {
		panic(ErrShape)
	}
	if y.Len() != ac {
		panic(ErrShape)
	}

	var w Dense
	if m == a {
		w = *m
	}
	w.reuseAs(ar, ac)

	// Copy over to the new memory if necessary
	if m != a {
		w.Copy(a)
	}
	blas64.Ger(alpha, x.mat, y.mat, w.mat)
	*m = w
}