示例#1
0
文件: mesh.go 项目: c2-akula/mesh
// Mul computes the product of two matrices a,b and puts
// it in receiver.
// a = mxk, b = kxn, c = mxn
func (c *mesh) Mul(s float64, a, b Mesher) {
	m, k := a.Size()
	br, n := b.Size()

	var (
		icoff, iaoff, lboff int
		ctmp                []float64
		tmp                 float64
	)

	if k != br {
		panic("mesh: Mul: Columns of 'a' != Rows of 'b'")
	}

	aoff, boff, coff := k, n, n
	for i := 0; i < m; i++ {
		icoff = i * coff
		iaoff = i * aoff
		ctmp = c.elems[icoff : icoff+n]
		for l, v := range a.(*mesh).elems[iaoff : iaoff+k] {
			lboff = l * boff
			tmp = s * v
			if tmp != 0 {
				amd.DaxpyUnitary(tmp, b.(*mesh).elems[lboff:lboff+n], ctmp, ctmp)
			}
		}
	}
}
示例#2
0
文件: mesh.go 项目: c2-akula/mesh
// Sum computes the sum of meshes, m & n and puts
// result in receiver.
// m, n and o should have same dimensions.
// a*m + n = o
// we will calculate the sum of meshes using
// a slight variation of saxpy
// ie ax+by, x and y are vectors and
// a, b are scalars.
func (o *mesh) Sum(a, b float64, m, n Mesher) {

	// the size of all the meshes are assumed to be
	// equal and no check is performed, we want this
	// to be as fast an operation as possible
	_, mc := m.Size() // no. of cols of the meshes

	mv := make([]float64, mc) // col vector of m
	nv := make([]float64, mc) // col vector of n
	ov := make([]float64, mc) // col vector of o

	// we will scale the meshes
	if a == 0 && b == 1 {
		// z = 0*x + y
		// we just copy n into o
		o.Clone(n)
		return
	}

	if b == 0 && a == 1 {
		// z = x + 0*y
		// we just copy m into o
		o.Clone(m)
		return
	}

	if a == 1 && b != 1 {
		// z = x + by
		// we scale n
		ns := n.Slice()
		for j := range ns {
			ns[j] *= b
		}
	} else if a != 1 && b == 1 {
		// z = ax + y
		// we scale m
		ms := m.Slice()
		for j := range ms {
			ms[j] *= a
		}
	} else if a == 0 && b == 0 {
		o.Zero()
		return
	}

	// we add the meshes by cols
	for j := 0; j < mc; j++ {
		m.GetCol(mv, j)
		n.GetCol(nv, j)
		amd.DaxpyUnitary(a, mv, nv, ov)
		o.SetCol(ov, j)
	}
}
示例#3
0
文件: vec.go 项目: c2-akula/mesh
// Sum computes the sum of two vectors
func Sum(s float64, a, b, c []float64) {
	amd.DaxpyUnitary(s, a, b, c)
}