Пример #1
0
/*
 * Reduce upper triangular matrix to tridiagonal.
 *
 * Elementary reflectors Q = H(n-1)...H(2)H(1) are stored on upper
 * triangular part of A. Reflector H(n-1) saved at column A(n) and
 * scalar multiplier to tau[n-1]. If parameter `tail` is true then
 * this function is used to reduce tail part of partially reduced
 * matrix and tau-vector partitioning is starting from last position.
 */
func unblkReduceTridiagUpper(A, tauq, W *cmat.FloatMatrix, tail bool) {
	var ATL, ABR cmat.FloatMatrix
	var A00, a01, a11, A22 cmat.FloatMatrix
	var tqT, tqB, tq0, tauq1, tq2 cmat.FloatMatrix
	var y21 cmat.FloatMatrix
	var v0 float64

	toff := 1
	if tail {
		toff = 0
	}
	util.Partition2x2(
		&ATL, nil,
		nil, &ABR, A, 0, 0, util.PBOTTOMRIGHT)
	util.Partition2x1(
		&tqT,
		&tqB, tauq, toff, util.PBOTTOM)

	for n(&ATL) > 0 {
		util.Repartition2x2to3x3(&ATL,
			&A00, &a01, nil,
			nil, &a11, nil,
			nil, nil, &A22, A, 1, util.PTOPLEFT)
		util.Repartition2x1to3x1(&tqT,
			&tq0,
			&tauq1,
			&tq2, tauq, 1, util.PTOP)
		// set temp vectors for this round
		y21.SetBuf(n(&A00), 1, n(&A00), W.Data())
		// ------------------------------------------------------

		// Compute householder to zero super-diagonal entries
		computeHouseholderRev(&a01, &tauq1)
		tauqv := tauq1.Get(0, 0)

		// set superdiagonal to unit
		v0 = a01.Get(-1, 0)
		a01.Set(-1, 0, 1.0)

		// y21 := A22*a12t
		blasd.MVMultSym(&y21, &A00, &a01, tauqv, 0.0, gomas.UPPER)
		// beta := tauq*a12t*y21
		beta := tauqv * blasd.Dot(&a01, &y21)
		// y21  := y21 - 0.5*beta*a125
		blasd.Axpy(&y21, &a01, -0.5*beta)
		// A22 := A22 - a12t*y21.T - y21*a12.T
		blasd.MVUpdate2Sym(&A00, &a01, &y21, -1.0, gomas.UPPER)

		// restore superdiagonal value
		a01.Set(-1, 0, v0)
		// ------------------------------------------------------
		util.Continue3x3to2x2(
			&ATL, nil,
			nil, &ABR, &A00, &a11, &A22, A, util.PTOPLEFT)
		util.Continue3x1to2x1(
			&tqT,
			&tqB, &tq0, &tauq1, tauq, util.PTOP)
	}
}
Пример #2
0
/*
 * Tridiagonal reduction of LOWER triangular symmetric matrix, zero elements below 1st
 * subdiagonal:
 *
 *   A =  (1 - tau*u*u.t)*A*(1 - tau*u*u.T)
 *     =  (I - tau*( 0   0   )) (a11 a12) (I - tau*( 0  0   ))
 *        (        ( 0  u*u.t)) (a21 A22) (        ( 0 u*u.t))
 *
 *  a11, a12, a21 not affected
 *
 *  from LEFT:
 *    A22 = A22 - tau*u*u.T*A22
 *  from RIGHT:
 *    A22 = A22 - tau*A22*u.u.T
 *
 *  LEFT and RIGHT:
 *    A22   = A22 - tau*u*u.T*A22 - tau*(A22 - tau*u*u.T*A22)*u*u.T
 *          = A22 - tau*u*u.T*A22 - tau*A22*u*u.T + tau*tau*u*u.T*A22*u*u.T
 *    [x    = tau*A22*u (vector)]  (SYMV)
 *    A22   = A22 - u*x.T - x*u.T + tau*u*u.T*x*u.T
 *    [beta = tau*u.T*x (scalar)]  (DOT)
 *          = A22 - u*x.T - x*u.T + beta*u*u.T
 *          = A22 - u*(x - 0.5*beta*u).T - (x - 0.5*beta*u)*u.T
 *    [w    = x - 0.5*beta*u]      (AXPY)
 *          = A22 - u*w.T - w*u.T  (SYR2)
 *
 * Result of reduction for N = 5:
 *    ( d  .  .  . . )
 *    ( e  d  .  . . )
 *    ( v1 e  d  . . )
 *    ( v1 v2 e  d . )
 *    ( v1 v2 v3 e d )
 */
func unblkReduceTridiagLower(A, tauq, W *cmat.FloatMatrix) {
	var ATL, ABR cmat.FloatMatrix
	var A00, a11, a21, A22 cmat.FloatMatrix
	var tqT, tqB, tq0, tauq1, tq2 cmat.FloatMatrix
	var y21 cmat.FloatMatrix
	var v0 float64

	util.Partition2x2(
		&ATL, nil,
		nil, &ABR, A, 0, 0, util.PTOPLEFT)
	util.Partition2x1(
		&tqT,
		&tqB, tauq, 0, util.PTOP)

	for m(&ABR) > 0 && n(&ABR) > 0 {
		util.Repartition2x2to3x3(&ATL,
			&A00, nil, nil,
			nil, &a11, nil,
			nil, &a21, &A22, A, 1, util.PBOTTOMRIGHT)
		util.Repartition2x1to3x1(&tqT,
			&tq0,
			&tauq1,
			&tq2, tauq, 1, util.PBOTTOM)
		// set temp vectors for this round
		y21.SetBuf(n(&A22), 1, n(&A22), W.Data())
		// ------------------------------------------------------

		// Compute householder to zero subdiagonal entries
		computeHouseholderVec(&a21, &tauq1)
		tauqv := tauq1.Get(0, 0)

		// set subdiagonal to unit
		v0 = a21.Get(0, 0)
		a21.Set(0, 0, 1.0)

		// y21 := tauq*A22*a21
		blasd.MVMultSym(&y21, &A22, &a21, tauqv, 0.0, gomas.LOWER)
		// beta := tauq*a21.T*y21
		beta := tauqv * blasd.Dot(&a21, &y21)
		// y21  := y21 - 0.5*beta*a21
		blasd.Axpy(&y21, &a21, -0.5*beta)
		// A22 := A22 - a21*y21.T - y21*a21.T
		blasd.MVUpdate2Sym(&A22, &a21, &y21, -1.0, gomas.LOWER)

		// restore subdiagonal
		a21.Set(0, 0, v0)
		// ------------------------------------------------------
		util.Continue3x3to2x2(
			&ATL, nil,
			nil, &ABR, &A00, &a11, &A22, A, util.PBOTTOMRIGHT)
		util.Continue3x1to2x1(
			&tqT,
			&tqB, &tq0, &tauq1, tauq, util.PBOTTOM)
	}
}
Пример #3
0
/*
 * This is adaptation of TRIRED_LAZY_UNB algorithm from (1).
 */
func unblkBuildTridiagUpper(A, tauq, Y, W *cmat.FloatMatrix) {
	var ATL, ABR cmat.FloatMatrix
	var A00, a01, A02, a11, a12, A22 cmat.FloatMatrix
	var YTL, YBR cmat.FloatMatrix
	var Y00, y01, Y02, y11, y12, Y22 cmat.FloatMatrix
	var tqT, tqB, tq0, tauq1, tq2 cmat.FloatMatrix
	var w12 cmat.FloatMatrix
	var v0 float64

	util.Partition2x2(
		&ATL, nil,
		nil, &ABR, A, 0, 0, util.PBOTTOMRIGHT)
	util.Partition2x2(
		&YTL, nil,
		nil, &YBR, Y, 0, 0, util.PBOTTOMRIGHT)
	util.Partition2x1(
		&tqT,
		&tqB, tauq, 0, util.PBOTTOM)

	k := 0
	for k < n(Y) {
		util.Repartition2x2to3x3(&ATL,
			&A00, &a01, &A02,
			nil, &a11, &a12,
			nil, nil, &A22, A, 1, util.PTOPLEFT)
		util.Repartition2x2to3x3(&YTL,
			&Y00, &y01, &Y02,
			nil, &y11, &y12,
			nil, nil, &Y22, Y, 1, util.PTOPLEFT)
		util.Repartition2x1to3x1(&tqT,
			&tq0,
			&tauq1,
			&tq2, tauq, 1, util.PTOP)

		// set temp vectors for this round
		w12.SubMatrix(Y, -1, 0, 1, n(&Y02))
		// ------------------------------------------------------

		if n(&Y02) > 0 {
			aa := blasd.Dot(&a12, &y12)
			aa += blasd.Dot(&y12, &a12)
			a11.Set(0, 0, a11.Get(0, 0)-aa)

			// a01 := a01 - A02*y12
			blasd.MVMult(&a01, &A02, &y12, -1.0, 1.0, gomas.NONE)
			// a01 := a01 - Y02*a12
			blasd.MVMult(&a01, &Y02, &a12, -1.0, 1.0, gomas.NONE)

			// restore superdiagonal value
			a12.Set(0, 0, v0)
		}
		// Compute householder to zero subdiagonal entries
		computeHouseholderRev(&a01, &tauq1)
		tauqv := tauq1.Get(0, 0)

		// set sub&iagonal to unit
		v0 = a01.Get(-1, 0)
		a01.Set(-1, 0, 1.0)

		// y01 := tauq*A00*a01
		blasd.MVMultSym(&y01, &A00, &a01, tauqv, 0.0, gomas.UPPER)
		// w12 := A02.T*a01
		blasd.MVMult(&w12, &A02, &a01, 1.0, 0.0, gomas.TRANS)
		// y01 := y01 - Y02*(A02.T*a01)
		blasd.MVMult(&y01, &Y02, &w12, -tauqv, 1.0, gomas.NONE)
		// w12 := Y02.T*a01
		blasd.MVMult(&w12, &Y02, &a01, 1.0, 0.0, gomas.TRANS)
		// y01 := y01 - A02*(Y02.T*a01)
		blasd.MVMult(&y01, &A02, &w12, -tauqv, 1.0, gomas.NONE)

		// beta := tauq*a01.T*y01
		beta := tauqv * blasd.Dot(&a01, &y01)
		// y01  := y01 - 0.5*beta*a01
		blasd.Axpy(&y01, &a01, -0.5*beta)

		// ------------------------------------------------------
		k += 1
		util.Continue3x3to2x2(
			&ATL, nil,
			nil, &ABR, &A00, &a11, &A22, A, util.PTOPLEFT)
		util.Continue3x3to2x2(
			&YTL, nil,
			nil, &YBR, &Y00, &y11, &Y22, A, util.PTOPLEFT)
		util.Continue3x1to2x1(
			&tqT,
			&tqB, &tq0, &tauq1, tauq, util.PTOP)
	}
	// restore superdiagonal value
	A.Set(m(&ATL)-1, n(&ATL), v0)
}
Пример #4
0
/*
 * This is adaptation of TRIRED_LAZY_UNB algorithm from (1).
 */
func unblkBuildTridiagLower(A, tauq, Y, W *cmat.FloatMatrix) {
	var ATL, ABR cmat.FloatMatrix
	var A00, a10, a11, A20, a21, A22 cmat.FloatMatrix
	var YTL, YBR cmat.FloatMatrix
	var Y00, y10, y11, Y20, y21, Y22 cmat.FloatMatrix
	var tqT, tqB, tq0, tauq1, tq2 cmat.FloatMatrix
	var w12 cmat.FloatMatrix
	var v0 float64

	util.Partition2x2(
		&ATL, nil,
		nil, &ABR, A, 0, 0, util.PTOPLEFT)
	util.Partition2x2(
		&YTL, nil,
		nil, &YBR, Y, 0, 0, util.PTOPLEFT)
	util.Partition2x1(
		&tqT,
		&tqB, tauq, 0, util.PTOP)

	k := 0
	for k < n(Y) {
		util.Repartition2x2to3x3(&ATL,
			&A00, nil, nil,
			&a10, &a11, nil,
			&A20, &a21, &A22, A, 1, util.PBOTTOMRIGHT)
		util.Repartition2x2to3x3(&YTL,
			&Y00, nil, nil,
			&y10, &y11, nil,
			&Y20, &y21, &Y22, Y, 1, util.PBOTTOMRIGHT)
		util.Repartition2x1to3x1(&tqT,
			&tq0,
			&tauq1,
			&tq2, tauq, 1, util.PBOTTOM)
		// set temp vectors for this round
		//w12.SetBuf(y10.Len(), 1, y10.Len(), W.Data())
		w12.SubMatrix(Y, 0, 0, 1, n(&Y00))
		// ------------------------------------------------------

		if n(&Y00) > 0 {
			aa := blasd.Dot(&a10, &y10)
			aa += blasd.Dot(&y10, &a10)
			a11.Set(0, 0, a11.Get(0, 0)-aa)

			// a21 := a21 - A20*y10
			blasd.MVMult(&a21, &A20, &y10, -1.0, 1.0, gomas.NONE)
			// a21 := a21 - Y20*a10
			blasd.MVMult(&a21, &Y20, &a10, -1.0, 1.0, gomas.NONE)

			// restore subdiagonal value
			a10.Set(0, -1, v0)
		}
		// Compute householder to zero subdiagonal entries
		computeHouseholderVec(&a21, &tauq1)
		tauqv := tauq1.Get(0, 0)

		// set subdiagonal to unit
		v0 = a21.Get(0, 0)
		a21.Set(0, 0, 1.0)

		// y21 := tauq*A22*a21
		blasd.MVMultSym(&y21, &A22, &a21, tauqv, 0.0, gomas.LOWER)
		// w12 := A20.T*a21
		blasd.MVMult(&w12, &A20, &a21, 1.0, 0.0, gomas.TRANS)
		// y21 := y21 - Y20*(A20.T*a21)
		blasd.MVMult(&y21, &Y20, &w12, -tauqv, 1.0, gomas.NONE)
		// w12 := Y20.T*a21
		blasd.MVMult(&w12, &Y20, &a21, 1.0, 0.0, gomas.TRANS)
		// y21 := y21 - A20*(Y20.T*a21)
		blasd.MVMult(&y21, &A20, &w12, -tauqv, 1.0, gomas.NONE)

		// beta := tauq*a21.T*y21
		beta := tauqv * blasd.Dot(&a21, &y21)
		// y21  := y21 - 0.5*beta*a21
		blasd.Axpy(&y21, &a21, -0.5*beta)

		// ------------------------------------------------------
		k += 1
		util.Continue3x3to2x2(
			&ATL, nil,
			nil, &ABR, &A00, &a11, &A22, A, util.PBOTTOMRIGHT)
		util.Continue3x3to2x2(
			&YTL, nil,
			nil, &YBR, &Y00, &y11, &Y22, A, util.PBOTTOMRIGHT)
		util.Continue3x1to2x1(
			&tqT,
			&tqB, &tq0, &tauq1, tauq, util.PBOTTOM)
	}
	// restore subdiagonal value
	A.Set(m(&ATL), n(&ATL)-1, v0)
}
Пример #5
0
/*
 * Compute unblocked bidiagonal reduction for A when M >= N
 *
 * Diagonal and first super/sub diagonal are overwritten with the
 * upper/lower bidiagonal matrix B.
 *
 * This computing (1-tauq*v*v.T)*A*(1-taup*u.u.T) from left to right.
 */
func unblkReduceBidiagLeft(A, tauq, taup, W *cmat.FloatMatrix) {
	var ATL, ABR cmat.FloatMatrix
	var A00, a11, a12t, a21, A22 cmat.FloatMatrix
	var tqT, tqB, tq0, tauq1, tq2 cmat.FloatMatrix
	var tpT, tpB, tp0, taup1, tp2 cmat.FloatMatrix
	var y21, z21 cmat.FloatMatrix
	var v0 float64

	util.Partition2x2(
		&ATL, nil,
		nil, &ABR, A, 0, 0, util.PTOPLEFT)
	util.Partition2x1(
		&tqT,
		&tqB, tauq, 0, util.PTOP)
	util.Partition2x1(
		&tpT,
		&tpB, taup, 0, util.PTOP)

	for m(&ABR) > 0 && n(&ABR) > 0 {
		util.Repartition2x2to3x3(&ATL,
			&A00, nil, nil,
			nil, &a11, &a12t,
			nil, &a21, &A22, A, 1, util.PBOTTOMRIGHT)
		util.Repartition2x1to3x1(&tqT,
			&tq0,
			&tauq1,
			&tq2, tauq, 1, util.PBOTTOM)
		util.Repartition2x1to3x1(&tpT,
			&tp0,
			&taup1,
			&tp2, taup, 1, util.PBOTTOM)

		// set temp vectors for this round
		y21.SetBuf(n(&a12t), 1, n(&a12t), W.Data())
		z21.SetBuf(m(&a21), 1, m(&a21), W.Data()[y21.Len():])
		// ------------------------------------------------------

		// Compute householder to zero subdiagonal entries
		computeHouseholder(&a11, &a21, &tauq1)

		// y21 := a12 + A22.T*a21
		blasd.Axpby(&y21, &a12t, 1.0, 0.0)
		blasd.MVMult(&y21, &A22, &a21, 1.0, 1.0, gomas.TRANSA)

		// a12t := a12t - tauq*y21
		tauqv := tauq1.Get(0, 0)
		blasd.Axpy(&a12t, &y21, -tauqv)

		// Compute householder to zero elements above 1st superdiagonal
		computeHouseholderVec(&a12t, &taup1)
		v0 = a12t.Get(0, 0)
		a12t.Set(0, 0, 1.0)
		taupv := taup1.Get(0, 0)

		// [v == a12t, u == a21]
		beta := blasd.Dot(&y21, &a12t)
		// z21 := tauq*beta*u
		blasd.Axpby(&z21, &a21, tauqv*beta, 0.0)
		// z21 := A22*v - z21
		blasd.MVMult(&z21, &A22, &a12t, 1.0, -1.0, gomas.NONE)
		// A22 := A22 - tauq*u*y21
		blasd.MVUpdate(&A22, &a21, &y21, -tauqv)
		// A22 := A22 - taup*z21*v
		blasd.MVUpdate(&A22, &z21, &a12t, -taupv)

		a12t.Set(0, 0, v0)
		// ------------------------------------------------------
		util.Continue3x3to2x2(
			&ATL, nil,
			nil, &ABR, &A00, &a11, &A22, A, util.PBOTTOMRIGHT)
		util.Continue3x1to2x1(
			&tqT,
			&tqB, &tq0, &tauq1, tauq, util.PBOTTOM)
		util.Continue3x1to2x1(
			&tpT,
			&tpB, &tp0, &taup1, taup, util.PBOTTOM)
	}
}
Пример #6
0
/*
 * This is adaptation of BIRED_LAZY_UNB algorithm from (1).
 *
 * Z matrix accumulates updates of row transformations i.e. first
 * Householder that zeros off diagonal entries on row. Vector z21
 * is updates for current round, Z20 are already accumulated updates.
 * Vector z21 updates a12 before next transformation.
 *
 * Y matrix accumulates updates on column tranformations ie Householder
 * that zeros elements below sub-diagonal. Vector y21 is updates for current
 * round, Y20 are already accumulated updates.  Vector y21 updates
 * a21 befor next transformation.
 *
 * Z, Y matrices upper trigonal part is not needed, temporary vector
 * w00 that has maximum length of n(Y) is placed on the last column of
 * Z matrix on each iteration.
 */
func unblkBuildBidiagRight(A, tauq, taup, Y, Z *cmat.FloatMatrix) {
	var ATL, ABL, ABR cmat.FloatMatrix
	var A00, a01, A02, a10, a11, a12t, A20, a21, A22 cmat.FloatMatrix
	var YTL, YBR, ZTL, ZBR cmat.FloatMatrix
	var Y00, y10, Y20, y11, y21, Y22 cmat.FloatMatrix
	var Z00, z10, Z20, z11, z21, Z22 cmat.FloatMatrix
	var tqT, tqB, tq0, tauq1, tq2 cmat.FloatMatrix
	var tpT, tpB, tp0, taup1, tp2 cmat.FloatMatrix
	var w00 cmat.FloatMatrix
	var v0 float64

	// Y is workspace for building updates for first Householder.
	// And Z is space for build updates for second Householder
	// Y is n(A)-2,nb and Z is m(A)-1,nb

	util.Partition2x2(
		&ATL, nil,
		&ABL, &ABR, A, 0, 0, util.PTOPLEFT)
	util.Partition2x2(
		&YTL, nil,
		nil, &YBR, Y, 0, 0, util.PTOPLEFT)
	util.Partition2x2(
		&ZTL, nil,
		nil, &ZBR, Z, 0, 0, util.PTOPLEFT)
	util.Partition2x1(
		&tqT,
		&tqB, tauq, 0, util.PTOP)
	util.Partition2x1(
		&tpT,
		&tpB, taup, 0, util.PTOP)

	k := 0
	for k < n(Y) {
		util.Repartition2x2to3x3(&ATL,
			&A00, &a01, &A02,
			&a10, &a11, &a12t,
			&A20, &a21, &A22, A, 1, util.PBOTTOMRIGHT)
		util.Repartition2x2to3x3(&YTL,
			&Y00, nil, nil,
			&y10, &y11, nil,
			&Y20, &y21, &Y22, Y, 1, util.PBOTTOMRIGHT)
		util.Repartition2x2to3x3(&ZTL,
			&Z00, nil, nil,
			&z10, &z11, nil,
			&Z20, &z21, &Z22, Z, 1, util.PBOTTOMRIGHT)
		util.Repartition2x1to3x1(&tqT,
			&tq0,
			&tauq1,
			&tq2, tauq, 1, util.PBOTTOM)
		util.Repartition2x1to3x1(&tpT,
			&tp0,
			&taup1,
			&tp2, taup, 1, util.PBOTTOM)

		// set temp vectors for this round,
		w00.SubMatrix(Z, 0, n(Z)-1, m(&A02), 1)
		// ------------------------------------------------------
		// u10 == a10, U20 == A20, u21 == a21,
		// v10 == a01, V20 == A02, v21 == a12t
		if n(&Y20) > 0 {
			// a11 := a11 - u10t*z10 - y10*v10
			aa := blasd.Dot(&a10, &z10)
			aa += blasd.Dot(&y10, &a01)
			a11.Set(0, 0, a11.Get(0, 0)-aa)
			// a12t := a12t - V20*z10 - Z20*u10
			blasd.MVMult(&a12t, &A02, &y10, -1.0, 1.0, gomas.TRANS)
			blasd.MVMult(&a12t, &Z20, &a10, -1.0, 1.0, gomas.NONE)
			// a21 := a21 - Y20*v10 - U20*z10
			blasd.MVMult(&a21, &Y20, &a01, -1.0, 1.0, gomas.NONE)
			blasd.MVMult(&a21, &A20, &z10, -1.0, 1.0, gomas.NONE)
			// here restore bidiagonal entry
			a10.Set(0, -1, v0)
		}
		// Compute householder to zero superdiagonal entries
		computeHouseholder(&a11, &a12t, &taup1)
		taupv := taup1.Get(0, 0)

		// y21 := a21 + A22*v21 - Y20*U20.T*v21 - V20*Z20.T*v21
		blasd.Axpby(&y21, &a21, 1.0, 0.0)
		blasd.MVMult(&y21, &A22, &a12t, 1.0, 1.0, gomas.NONE)

		// w00 := U20.T*v21 [= A02*a12t]
		blasd.MVMult(&w00, &A02, &a12t, 1.0, 0.0, gomas.NONE)
		// y21 := y21 - U20*w00 [U20 == A20]
		blasd.MVMult(&y21, &Y20, &w00, -1.0, 1.0, gomas.NONE)
		// w00 := Z20.T*v21
		blasd.MVMult(&w00, &Z20, &a12t, 1.0, 0.0, gomas.TRANS)
		// y21 := y21 - V20*w00  [V20 == A02.T]
		blasd.MVMult(&y21, &A20, &w00, -1.0, 1.0, gomas.NONE)

		// a21 := a21 - taup*y21
		blasd.Scale(&y21, taupv)
		blasd.Axpy(&a21, &y21, -1.0)

		// Compute householder to zero elements below 1st subdiagonal
		computeHouseholderVec(&a21, &tauq1)
		v0 = a21.Get(0, 0)
		a21.Set(0, 0, 1.0)
		tauqv := tauq1.Get(0, 0)

		// z21 := tauq*(A22*y - V20*Y20.T*u - Z20*U20.T*u - beta*v)
		// [v == a12t, u == a21]
		beta := blasd.Dot(&y21, &a21)
		// z21 := beta*v
		blasd.Axpby(&z21, &a12t, beta, 0.0)
		// w00 = Y20.T*u
		blasd.MVMult(&w00, &Y20, &a21, 1.0, 0.0, gomas.TRANS)
		// z21 = z21 + V20*w00 == A02.T*w00
		blasd.MVMult(&z21, &A02, &w00, 1.0, 1.0, gomas.TRANS)
		// w00 := U20.T*u  (U20.T == A20.T)
		blasd.MVMult(&w00, &A20, &a21, 1.0, 0.0, gomas.TRANS)
		// z21 := z21 + Z20*w00
		blasd.MVMult(&z21, &Z20, &w00, 1.0, 1.0, gomas.NONE)
		// z21 := -tauq*z21 + tauq*A22*v
		blasd.MVMult(&z21, &A22, &a21, tauqv, -tauqv, gomas.TRANS)
		// ------------------------------------------------------
		k += 1
		util.Continue3x3to2x2(
			&ATL, nil,
			&ABL, &ABR, &A00, &a11, &A22, A, util.PBOTTOMRIGHT)
		util.Continue3x3to2x2(
			&YTL, nil,
			nil, &YBR, &Y00, &y11, &Y22, Y, util.PBOTTOMRIGHT)
		util.Continue3x3to2x2(
			&ZTL, nil,
			nil, &ZBR, &Z00, &z11, &Z22, Z, util.PBOTTOMRIGHT)
		util.Continue3x1to2x1(
			&tqT,
			&tqB, &tq0, &tauq1, tauq, util.PBOTTOM)
		util.Continue3x1to2x1(
			&tpT,
			&tpB, &tp0, &taup1, taup, util.PBOTTOM)
	}
	// restore
	ABL.Set(0, -1, v0)
}
Пример #7
0
// unblocked LU decomposition with pivots: FLAME LU variant 3; Left-looking
func unblockedLUpiv(A *cmat.FloatMatrix, p *Pivots, offset int, conf *gomas.Config) *gomas.Error {
	var err *gomas.Error = nil
	var ATL, ATR, ABL, ABR cmat.FloatMatrix
	var A00, a01, A02, a10, a11, a12, A20, a21, A22 cmat.FloatMatrix
	var AL, AR, A0, a1, A2, aB1, AB0 cmat.FloatMatrix
	var pT, pB, p0, p1, p2 Pivots

	err = nil
	util.Partition2x2(
		&ATL, &ATR,
		&ABL, &ABR, A, 0, 0, util.PTOPLEFT)
	util.Partition1x2(
		&AL, &AR, A, 0, util.PLEFT)
	partitionPivot2x1(
		&pT,
		&pB, *p, 0, util.PTOP)

	for m(&ATL) < m(A) && n(&ATL) < n(A) {
		util.Repartition2x2to3x3(&ATL,
			&A00, &a01, &A02,
			&a10, &a11, &a12,
			&A20, &a21, &A22 /**/, A, 1, util.PBOTTOMRIGHT)
		util.Repartition1x2to1x3(&AL,
			&A0, &a1, &A2 /**/, A, 1, util.PRIGHT)
		repartPivot2x1to3x1(&pT,
			&p0, &p1, &p2 /**/, *p, 1, util.PBOTTOM)

		// apply previously computed pivots on current column
		applyPivots(&a1, p0)

		// a01 = trilu(A00) \ a01 (TRSV)
		blasd.MVSolveTrm(&a01, &A00, 1.0, gomas.LOWER|gomas.UNIT)
		// a11 = a11 - a10 *a01
		aval := a11.Get(0, 0) - blasd.Dot(&a10, &a01)
		a11.Set(0, 0, aval)
		// a21 = a21 -A20*a01
		blasd.MVMult(&a21, &A20, &a01, -1.0, 1.0, gomas.NONE)

		// pivot index on current column [a11, a21].T
		aB1.Column(&ABR, 0)
		p1[0] = pivotIndex(&aB1)
		// pivots to current column
		applyPivots(&aB1, p1)

		// a21 = a21 / a11
		if aval == 0.0 {
			if err == nil {
				ij := m(&ATL) + p1[0] - 1
				err = gomas.NewError(gomas.ESINGULAR, "DecomposeLU", ij)
			}
		} else {
			blasd.InvScale(&a21, a11.Get(0, 0))
		}

		// apply pivots to previous columns
		AB0.SubMatrix(&ABL, 0, 0)
		applyPivots(&AB0, p1)
		// scale last pivots to origin matrix row numbers
		p1[0] += m(&ATL)

		util.Continue3x3to2x2(
			&ATL, &ATR,
			&ABL, &ABR, &A00, &a11, &A22, A, util.PBOTTOMRIGHT)
		util.Continue1x3to1x2(
			&AL, &AR, &A0, &a1, A, util.PRIGHT)
		contPivot3x1to2x1(
			&pT,
			&pB, p0, p1, *p, util.PBOTTOM)
	}
	if n(&ATL) < n(A) {
		applyPivots(&ATR, *p)
		blasd.SolveTrm(&ATR, &ATL, 1.0, gomas.LEFT|gomas.UNIT|gomas.LOWER, conf)
	}
	return err
}