func TestPartition2D(t *testing.T) {
var ATL, ATR, ABL, ABR, As cmat.FloatMatrix
var A00, a01, A02, a10, a11, a12, A20, a21, A22 cmat.FloatMatrix
csource := cmat.NewFloatConstSource(1.0)
A := cmat.NewMatrix(6, 6)
As.SubMatrix(A, 1, 1, 4, 4)
As.SetFrom(csource)
Partition2x2(&ATL, &ATR, &ABL, &ABR, &As, 0, 0, PTOPLEFT)
t.Logf("ATL:\n%v\n", &ATL)
t.Logf("n(ATL)=%d, n(As)=%d\n", n(&ATL), n(&As))
k := 0
for n(&ATL) < n(&As) && k < n(&As) {
Repartition2x2to3x3(&ATL,
&A00, &a01, &A02,
&a10, &a11, &a12,
&A20, &a21, &A22, &As, 1, PBOTTOMRIGHT)
t.Logf("n(A00)=%d, n(a01)=%d, n(A02)=%d\n", n(&A00), n(&a01), n(&A02))
t.Logf("n(a10)=%d, n(a11)=%d, n(a12)=%d\n", n(&a10), n(&a11), n(&a12))
t.Logf("n(A20)=%d, n(a21)=%d, n(A22)=%d\n", n(&A20), n(&a21), n(&A22))
//t.Logf("n(a12)=%d [%d], n(a11)=%d\n", n(&a12), a12.Len(), a11.Len())
a11.Set(0, 0, a11.Get(0, 0)+1.0)
addConst(&a21, -2.0)
Continue3x3to2x2(&ATL, &ATR, &ABL, &ABR, &A00, &a11, &A22, &As, PBOTTOMRIGHT)
t.Logf("n(ATL)=%d, n(As)=%d\n", n(&ATL), n(&As))
k += 1
}
t.Logf("A:\n%v\n", A)
}
/*
* 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)
}
}
func blkReduceTridiagUpper(A, tauq, Y, W *cmat.FloatMatrix, lb int, conf *gomas.Config) {
var ATL, ABR cmat.FloatMatrix
var A00, A01, A11, A22 cmat.FloatMatrix
var YT, YB, Y0, Y1, Y2 cmat.FloatMatrix
var tqT, tqB, tq0, tauq1, tq2 cmat.FloatMatrix
var v0 float64
util.Partition2x2(
&ATL, nil,
nil, &ABR, A, 0, 0, util.PBOTTOMRIGHT)
util.Partition2x1(
&YT,
&YB, Y, 0, util.PBOTTOM)
util.Partition2x1(
&tqT,
&tqB, tauq, 1, util.PBOTTOM)
for m(&ATL)-lb > 0 {
util.Repartition2x2to3x3(&ATL,
&A00, &A01, nil,
nil, &A11, nil,
nil, nil, &A22, A, lb, util.PTOPLEFT)
util.Repartition2x1to3x1(&YT,
&Y0,
&Y1,
&Y2, Y, lb, util.PTOP)
util.Repartition2x1to3x1(&tqT,
&tq0,
&tauq1,
&tq2, tauq, lb, util.PTOP)
// ------------------------------------------------------
unblkBuildTridiagUpper(&ATL, &tauq1, &YT, W)
// set subdiagonal entry to unit
v0 = A01.Get(-1, 0)
A01.Set(-1, 0, 1.0)
// A22 := A22 - A01*Y0.T - Y0*A01.T
blasd.Update2Sym(&A00, &A01, &Y0, -1.0, 1.0, gomas.UPPER, conf)
// restore subdiagonal entry
A01.Set(-1, 0, v0)
// ------------------------------------------------------
util.Continue3x3to2x2(
&ATL, nil,
nil, &ABR, &A00, &A11, &A22, A, util.PTOPLEFT)
util.Continue3x1to2x1(
&YT,
&YB, &Y0, &Y1, Y, util.PTOP)
util.Continue3x1to2x1(
&tqT,
&tqB, &tq0, &tauq1, tauq, util.PTOP)
}
if m(&ATL) > 0 {
unblkReduceTridiagUpper(&ATL, &tqT, W, true)
}
}
/*
* like LAPACK/dlafrt.f
*
* Build block reflector T from HH reflector stored in TriLU(A) and coefficients
* in tau.
*
* Q = I - Y*T*Y.T; Householder H = I - tau*v*v.T
*
* T = | T z | z = -tau*T*Y.T*v
* | 0 c | c = tau
*
* Q = H(1)H(2)...H(k) building forward here.
*/
func unblkQLBlockReflector(T, A, tau *cmat.FloatMatrix) {
var ATL, ABR cmat.FloatMatrix
var A00, a01, a11, A02, a12, A22 cmat.FloatMatrix
var TTL, TBR cmat.FloatMatrix
var T00, t11, t21, T22 cmat.FloatMatrix
var tT, tB cmat.FloatMatrix
var t0, tau1, t2 cmat.FloatMatrix
util.Partition2x2(
&ATL, nil,
nil, &ABR, A, 0, 0, util.PBOTTOMRIGHT)
util.Partition2x2(
&TTL, nil,
nil, &TBR, T, 0, 0, util.PBOTTOMRIGHT)
util.Partition2x1(
&tT,
&tB, tau, 0, util.PBOTTOM)
for m(&ATL) > 0 && n(&ATL) > 0 {
util.Repartition2x2to3x3(&ATL,
&A00, &a01, &A02,
nil, &a11, &a12,
nil, nil, &A22, A, 1, util.PTOPLEFT)
util.Repartition2x2to3x3(&TTL,
&T00, nil, nil,
nil, &t11, nil,
nil, &t21, &T22, T, 1, util.PTOPLEFT)
util.Repartition2x1to3x1(&tT,
&t0,
&tau1,
&t2, tau, 1, util.PTOP)
// --------------------------------------------------
// t11 := tau
tauval := tau1.Get(0, 0)
if tauval != 0.0 {
t11.Set(0, 0, tauval)
// t21 := -tauval*(a12.T + &A02.T*a12)
blasd.Axpby(&t21, &a12, 1.0, 0.0)
blasd.MVMult(&t21, &A02, &a01, -tauval, -tauval, gomas.TRANSA)
// t21 := T22*t01
blasd.MVMultTrm(&t21, &T22, 1.0, gomas.LOWER)
}
// --------------------------------------------------
util.Continue3x3to2x2(
&ATL, nil,
nil, &ABR, &A00, &a11, &A22, A, util.PTOPLEFT)
util.Continue3x3to2x2(
&TTL, nil,
nil, &TBR, &T00, &t11, &T22, T, util.PTOPLEFT)
util.Continue3x1to2x1(
&tT,
&tB, &t0, &tau1, tau, util.PTOP)
}
}
/*
* like LAPACK/dlafrt.f
*
* Build block reflector T from HH reflector stored in TriLU(A) and coefficients
* in tau.
*
* Q = I - Y*T*Y.T; Householder H = I - tau*v*v.T
*
* T = | T 0 | z = -tau*T*Y.T*v
* | z c | c = tau
*
* Q = H(1)H(2)...H(k) building forward here.
*/
func unblkBlockReflectorRQ(T, A, tau *cmat.FloatMatrix) {
var ATL, ABR cmat.FloatMatrix
var A00, a10, A20, a11, a21, A22 cmat.FloatMatrix
var TTL, TBR cmat.FloatMatrix
var T00, t11, t21, T22 cmat.FloatMatrix
var tT, tB cmat.FloatMatrix
var t0, tau1, t2 cmat.FloatMatrix
util.Partition2x2(
&ATL, nil,
nil, &ABR /**/, A, 0, 0, util.PBOTTOMRIGHT)
util.Partition2x2(
&TTL, nil,
nil, &TBR /**/, T, 0, 0, util.PBOTTOMRIGHT)
util.Partition2x1(
&tT,
&tB /**/, tau, 0, util.PBOTTOM)
for m(&ATL) > 0 && n(&ATL) > 0 {
util.Repartition2x2to3x3(&ATL,
&A00, nil, nil,
&a10, &a11, nil,
&A20, &a21, &A22 /**/, A, 1, util.PTOPLEFT)
util.Repartition2x2to3x3(&TTL,
&T00, nil, nil,
nil, &t11, nil,
nil, &t21, &T22 /**/, T, 1, util.PTOPLEFT)
util.Repartition2x1to3x1(&tT,
&t0,
&tau1,
&t2 /**/, tau, 1, util.PTOP)
// --------------------------------------------------
// t11 := tau
tauval := tau1.Get(0, 0)
if tauval != 0.0 {
t11.Set(0, 0, tauval)
// t21 := -tauval*(a21 + A20*a10)
blasd.Axpby(&t21, &a21, 1.0, 0.0)
blasd.MVMult(&t21, &A20, &a10, -tauval, -tauval, gomas.NONE)
// t21 := T22*t21
blasd.MVMultTrm(&t21, &T22, 1.0, gomas.LOWER)
}
// --------------------------------------------------
util.Continue3x3to2x2(
&ATL, nil,
nil, &ABR /**/, &A00, &a11, &A22, A, util.PTOPLEFT)
util.Continue3x3to2x2(
&TTL, nil,
nil, &TBR /**/, &T00, &t11, &T22, T, util.PTOPLEFT)
util.Continue3x1to2x1(
&tT,
&tB /**/, &t0, &tau1, tau, util.PTOP)
}
}
/*
* like LAPACK/dlafrt.f
*
* Build block reflector T from HH reflector stored in TriLU(A) and coefficients
* in tau.
*
* Q = I - Y*T*Y.T; Householder H = I - tau*v*v.T
*
* T = | T z | z = -tau*T*Y.T*v
* | 0 c | c = tau
*
* Q = H(1)H(2)...H(k) building forward here.
*/
func unblkBlockReflectorLQ(T, A, tau *cmat.FloatMatrix) {
var ATL, ATR, ABL, ABR cmat.FloatMatrix
var A00, a01, A02, a11, a12, A22 cmat.FloatMatrix
var TTL, TTR, TBL, TBR cmat.FloatMatrix
var T00, t01, T02, t11, t12, T22 cmat.FloatMatrix
var tT, tB cmat.FloatMatrix
var t0, tau1, t2 cmat.FloatMatrix
util.Partition2x2(
&ATL, &ATR,
&ABL, &ABR, A, 0, 0, util.PTOPLEFT)
util.Partition2x2(
&TTL, &TTR,
&TBL, &TBR, T, 0, 0, util.PTOPLEFT)
util.Partition2x1(
&tT,
&tB, tau, 0, util.PTOP)
for m(&ABR) > 0 && n(&ABR) > 0 {
util.Repartition2x2to3x3(&ATL,
&A00, &a01, &A02,
nil, &a11, &a12,
nil, nil, &A22, A, 1, util.PBOTTOMRIGHT)
util.Repartition2x2to3x3(&TTL,
&T00, &t01, &T02,
nil, &t11, &t12,
nil, nil, &T22, T, 1, util.PBOTTOMRIGHT)
util.Repartition2x1to3x1(&tT,
&t0,
&tau1,
&t2, tau, 1, util.PBOTTOM)
// --------------------------------------------------
// t11 := tau
tauval := tau1.Get(0, 0)
if tauval != 0.0 {
t11.Set(0, 0, tauval)
// t01 := -tauval*(a01 + A02*a12)
blasd.Axpby(&t01, &a01, 1.0, 0.0)
blasd.MVMult(&t01, &A02, &a12, -tauval, -tauval, gomas.NONE)
// t01 := T00*t01
blasd.MVMultTrm(&t01, &T00, 1.0, gomas.UPPER)
}
// --------------------------------------------------
util.Continue3x3to2x2(
&ATL, &ATR,
&ABL, &ABR, &A00, &a11, &A22, A, util.PBOTTOMRIGHT)
util.Continue3x3to2x2(
&TTL, &TTR,
&TBL, &TBR, &T00, &t11, &T22, T, util.PBOTTOMRIGHT)
util.Continue3x1to2x1(
&tT,
&tB, &t0, &tau1, tau, util.PBOTTOM)
}
}
/*
* 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)
}
}
/*
* Unblocked code for generating M by N matrix Q with orthogonal columns which
* are defined as the first N columns of the product of K first elementary
* reflectors.
*
* Parameters nk = n(A)-K, mk = m(A)-K define the initial partitioning of
* matrix A.
*
* Q = H(k)H(k-1)...H(1) , 0 < k <= M, where H(i) = I - tau*v*v.T
*
* Computation is ordered as H(k)*H(k-1)...*H(1)*I ie. from bottom to top.
*
* If k < M rows k+1:M are cleared and diagonal entries [k+1:M,k+1:M] are
* set to unit. Then the matrix Q is generated by right multiplying elements below
* of i'th elementary reflector H(i).
*
* Compatible to lapack.xORG2L subroutine.
*/
func unblkBuildLQ(A, Tvec, W *cmat.FloatMatrix, mk, nk int, mayClear bool) {
var ATL, ATR, ABL, ABR cmat.FloatMatrix
var A00, a10, a11, a12, a21, A22 cmat.FloatMatrix
var tT, tB cmat.FloatMatrix
var t0, tau1, t2, w12, D cmat.FloatMatrix
util.Partition2x2(
&ATL, &ATR,
&ABL, &ABR, A, mk, nk, util.PBOTTOMRIGHT)
util.Partition2x1(
&tT,
&tB, Tvec, mk, util.PBOTTOM)
// zero the bottom part
if mk > 0 && mayClear {
blasd.Scale(&ABL, 0.0)
blasd.Scale(&ABR, 0.0)
D.Diag(&ABR)
blasd.Add(&D, 1.0)
}
for m(&ATL) > 0 && n(&ATL) > 0 {
util.Repartition2x2to3x3(&ATL,
&A00, nil, nil,
&a10, &a11, &a12,
nil, &a21, &A22, A, 1, util.PTOPLEFT)
util.Repartition2x1to3x1(&tT,
&t0,
&tau1,
&t2, Tvec, 1, util.PTOP)
// ------------------------------------------------------
w12.SubMatrix(W, 0, 0, a21.Len(), 1)
applyHouseholder2x1(&tau1, &a12, &a21, &A22, &w12, gomas.RIGHT)
blasd.Scale(&a12, -tau1.Get(0, 0))
a11.Set(0, 0, 1.0-tau1.Get(0, 0))
// zero
blasd.Scale(&a10, 0.0)
// ------------------------------------------------------
util.Continue3x3to2x2(
&ATL, &ATR,
&ABL, &ABR, &A00, &a11, &A22, A, util.PTOPLEFT)
util.Continue3x1to2x1(
&tT,
&tB, &t0, &tau1, Tvec, util.PTOP)
}
}
/*
* Unblocked code for generating M by N matrix Q with orthogonal columns which
* are defined as the last N columns of the product of K first elementary
* reflectors.
*
* Parameter nk is last nk elementary reflectors that are not used in computing
* the matrix Q. Parameter mk length of the first unused elementary reflectors
* First nk columns are zeroed and subdiagonal mk-nk is set to unit.
*
* Compatible with lapack.DORG2L subroutine.
*/
func unblkBuildQL(A, Tvec, W *cmat.FloatMatrix, mk, nk int, mayClear bool) {
var ATL, ATR, ABL, ABR cmat.FloatMatrix
var A00, a01, a10, a11, a21, A22 cmat.FloatMatrix
var tT, tB cmat.FloatMatrix
var t0, tau1, t2, w12, D cmat.FloatMatrix
// (mk, nk) = (rows, columns) of upper left partition
util.Partition2x2(
&ATL, &ATR,
&ABL, &ABR, A, mk, nk, util.PTOPLEFT)
util.Partition2x1(
&tT,
&tB, Tvec, nk, util.PTOP)
// zero the left side
if nk > 0 && mayClear {
blasd.Scale(&ABL, 0.0)
blasd.Scale(&ATL, 0.0)
D.Diag(&ATL, nk-mk)
blasd.Add(&D, 1.0)
}
for m(&ABR) > 0 && n(&ABR) > 0 {
util.Repartition2x2to3x3(&ATL,
&A00, &a01, nil,
&a10, &a11, nil,
nil, &a21, &A22, A, 1, util.PBOTTOMRIGHT)
util.Repartition2x1to3x1(&tT,
&t0,
&tau1,
&t2, Tvec, 1, util.PBOTTOM)
// ------------------------------------------------------
w12.SubMatrix(W, 0, 0, a10.Len(), 1)
applyHouseholder2x1(&tau1, &a01, &a10, &A00, &w12, gomas.LEFT)
blasd.Scale(&a01, -tau1.Get(0, 0))
a11.Set(0, 0, 1.0-tau1.Get(0, 0))
// zero bottom elements
blasd.Scale(&a21, 0.0)
// ------------------------------------------------------
util.Continue3x3to2x2(
&ATL, &ATR,
&ABL, &ABR, &A00, &a11, &A22, A, util.PBOTTOMRIGHT)
util.Continue3x1to2x1(
&tT,
&tB, &t0, &tau1, Tvec, util.PBOTTOM)
}
}
/*
* Apply diagonal pivot (row and column swapped) to symmetric matrix blocks.
*
* LOWER triangular; moving from top-left to bottom-right
*
* -----------------------
* | d
* | x P1 x x x P2 -- current row/col 'srcix'
* | x S2 d x x x
* | x S2 x d x x
* | x S2 x x d x
* | x P2 D2 D2 D2 P3 -- swap with row/col 'dstix'
* | x S3 x x x D3 d
* | x S3 x x x D3 x d
* (AR)
*/
func applyBKPivotSymLower(AR *cmat.FloatMatrix, srcix, dstix int) {
var s, d cmat.FloatMatrix
// S2 -- D2
s.SubMatrix(AR, srcix+1, srcix, dstix-srcix-1, 1)
d.SubMatrix(AR, dstix, srcix+1, 1, dstix-srcix-1)
blasd.Swap(&s, &d)
// S3 -- D3
s.SubMatrix(AR, dstix+1, srcix, m(AR)-dstix-1, 1)
d.SubMatrix(AR, dstix+1, dstix, m(AR)-dstix-1, 1)
blasd.Swap(&s, &d)
// swap P1 and P3
p1 := AR.Get(srcix, srcix)
p3 := AR.Get(dstix, dstix)
AR.Set(srcix, srcix, p3)
AR.Set(dstix, dstix, p1)
return
}
/*
* Apply diagonal pivot (row and column swapped) to symmetric matrix blocks.
*
* UPPER triangular; moving from bottom-right to top-left
*
* d x D3 x x x S3 x |
* d D3 x x x S3 x |
* P3 D2 D2 D2 P2 x | -- dstinx
* d x x S2 x |
* d x S2 x |
* d S2 x |
* P1 x | -- srcinx
* d |
* ----------------------
* (ABR)
*/
func applyBKPivotSymUpper(AR *cmat.FloatMatrix, srcix, dstix int) {
var s, d cmat.FloatMatrix
// AL is ATL, AR is ATR; P1 is AL[srcix, srcix];
// S2 -- D2
s.SubMatrix(AR, dstix+1, srcix, srcix-dstix-1, 1)
d.SubMatrix(AR, dstix, dstix+1, 1, srcix-dstix-1)
blasd.Swap(&s, &d)
// S3 -- D3
s.SubMatrix(AR, 0, srcix, dstix, 1)
d.SubMatrix(AR, 0, dstix, dstix, 1)
blasd.Swap(&s, &d)
// swap P1 and P3
p1 := AR.Get(srcix, srcix)
p3 := AR.Get(dstix, dstix)
AR.Set(srcix, srcix, p3)
AR.Set(dstix, dstix, p1)
return
}
func TestViews(t *testing.T) {
var As cmat.FloatMatrix
N := 7
A := cmat.NewMatrix(N, N)
zeromean := cmat.NewFloatNormSource()
A.SetFrom(zeromean)
dlast := A.Get(-1, -1)
t.Logf("A[-1,-1] = %10.3e\n", dlast)
for i := 0; i < N; i++ {
As.SubMatrix(A, i, i)
As.Set(0, 0, As.Get(0, 0)+float64(i+1))
if N < 10 {
t.Logf("A[%d,%d] = %10.3e\n", i, i, As.Get(0, 0))
}
}
ok := float64(N)+dlast == A.Get(-1, -1)
nC := int(A.Get(-1, -1) - dlast)
t.Logf("add 1.0 %d times [%10.3e to %10.3e]: %v\n", nC, dlast, A.Get(-1, -1), ok)
}
/*
* Generates the real orthogonal matrix Q which is defined as the product of K elementary
* reflectors of order N embedded in matrix A as returned by TRDReduce().
*
* A On entry tridiagonal reduction as returned by TRDReduce().
* On exit the orthogonal matrix Q.
*
* tau Scalar coefficients of elementary reflectors.
*
* W Workspace
*
* K Number of reflectors , 0 < K < N
*
* flags LOWER or UPPER
*
* confs Optional blocking configuration
*
* If flags has UPPER set then
* Q = H(K)...H(1)H(0) where 0 < K < N-1
*
* If flags has LOWR set then
* Q = H(0)H(1)...H(K) where 0 < K < N-1
*/
func TRDBuild(A, tau, W *cmat.FloatMatrix, K, flags int, confs ...*gomas.Config) *gomas.Error {
var err *gomas.Error = nil
var Qh, tauh cmat.FloatMatrix
var s, d cmat.FloatMatrix
if K > m(A)-1 {
K = m(A) - 1
}
switch flags & (gomas.LOWER | gomas.UPPER) {
case gomas.LOWER:
// Shift Q matrix embedded in A right and fill first column
// unit column vector
for j := m(A) - 1; j > 0; j-- {
s.SubMatrix(A, j, j-1, m(A)-j, 1)
d.SubMatrix(A, j, j, m(A)-j, 1)
blasd.Copy(&d, &s)
A.Set(0, j, 0.0)
}
// zero first column and set first entry to one
d.Column(A, 0)
blasd.Scale(&d, 0.0)
d.Set(0, 0, 1.0)
Qh.SubMatrix(A, 1, 1, m(A)-1, m(A)-1)
tauh.SubMatrix(tau, 0, 0, m(A)-1, 1)
err = QRBuild(&Qh, &tauh, W, K, confs...)
case gomas.UPPER:
// Shift Q matrix embedded in A left and fill last column
// unit column vector
for j := 1; j < m(A); j++ {
s.SubMatrix(A, 0, j, j, 1)
d.SubMatrix(A, 0, j-1, j, 1)
blasd.Copy(&d, &s)
A.Set(-1, j-1, 0.0)
}
// zero last column and set last entry to one
d.Column(A, m(A)-1)
blasd.Scale(&d, 0.0)
d.Set(-1, 0, 1.0)
Qh.SubMatrix(A, 0, 0, m(A)-1, m(A)-1)
tauh.SubMatrix(tau, 0, 0, m(A)-1, 1)
err = QLBuild(&Qh, &tauh, W, K, confs...)
}
if err != nil {
err.Update("TRDBuild")
}
return err
}
/*
* Compute A[i:i+nr,c1;c2] = A[i:i+nr,c1;c2]*G(c,s)
*
* Applies Givens rotation to nr rows of columns c1, c2 of A starting at row.
*
*/
func ApplyGivensRight(A *cmat.FloatMatrix, c1, c2, row, nrow int, cos, sin float64) {
if row >= m(A) {
return
}
if c1 == c2 {
// one column
for k := row; k < row+nrow; k++ {
v0 := A.Get(k, c1)
A.Set(k, c1, cos*v0)
}
return
}
for k := row; k < row+nrow; k++ {
v0 := A.Get(k, c1)
v1 := A.Get(k, c2)
y0 := cos*v0 + sin*v1
y1 := cos*v1 - sin*v0
A.Set(k, c1, y0)
A.Set(k, c2, y1)
}
}
/*
* Compute A[i:i+1,j:j+nc] = G(c,s)*A[i:i+1,j:j+nc]
*
* Applies Givens rotation to nc columns on rows r1,r2 of A starting from col.
*/
func ApplyGivensLeft(A *cmat.FloatMatrix, r1, r2, col, ncol int, cos, sin float64) {
if col >= n(A) {
return
}
if r1 == r2 {
// one row
for k := col; k < col+ncol; k++ {
v0 := A.Get(r1, k)
A.Set(r1, k, cos*v0)
}
return
}
for k := col; k < col+ncol; k++ {
v0 := A.Get(r1, k)
v1 := A.Get(r2, k)
y0 := cos*v0 + sin*v1
y1 := cos*v1 - sin*v0
A.Set(r1, k, y0)
A.Set(r2, k, y1)
}
}
/*
* Apply diagonal pivot (row and column swapped) to symmetric matrix blocks.
* AR[0,0] is on diagonal and AL is block to the left of diagonal and AR the
* triangular diagonal block. Need to swap row and column.
*
* LOWER triangular; moving from top-left to bottom-right
*
* d
* x d
* x x d |
* --------------------------
* S1 S1 S1 | P1 x x x P2 -- current row
* x x x | S2 d x x x
* x x x | S2 x d x x
* x x x | S2 x x d x
* D1 D1 D1 | P2 D2 D2 D2 P3 -- swap with row 'index'
* x x x | S3 x x x D3 d
* x x x | S3 x x x D3 x d
* (ABL) (ABR)
*
* UPPER triangular; moving from bottom-right to top-left
*
* (ATL) (ATR)
* d x x D3 x x x | S3 x x
* d x D3 x x x | S3 x x
* d D3 x x x | S3 x x
* P3 D2 D2 D2| P2 D1 D1
* d x x | S2 x x
* d x | S2 x x
* d | S2 x x
* -----------------------------
* | P1 S1 S1
* | d x
* | d
* (ABR)
*/
func applyPivotSym(AL, AR *cmat.FloatMatrix, index int, flags int) {
var s, d cmat.FloatMatrix
lr, lc := AL.Size()
rr, rc := AR.Size()
if flags&gomas.LOWER != 0 {
// AL is [ABL]; AR is [ABR]; P1 is AR[0,0], P2 is AR[index, 0]
// S1 -- D1
s.SubMatrix(AL, 0, 0, 1, lc)
d.SubMatrix(AL, index, 0, 1, lc)
blasd.Swap(&s, &d)
// S2 -- D2
s.SubMatrix(AR, 1, 0, index-1, 1)
d.SubMatrix(AR, index, 1, 1, index-1)
blasd.Swap(&s, &d)
// S3 -- D3
s.SubMatrix(AR, index+1, 0, rr-index-1, 1)
d.SubMatrix(AR, index+1, index, rr-index-1, 1)
blasd.Swap(&s, &d)
// swap P1 and P3
p1 := AR.Get(0, 0)
p3 := AR.Get(index, index)
AR.Set(0, 0, p3)
AR.Set(index, index, p1)
return
}
if flags&gomas.UPPER != 0 {
// AL is merged from [ATL, ATR], AR is [ABR]; P1 is AR[0, 0]; P2 is AL[index, -1]
colno := lc - rc
// S1 -- D1; S1 is on the first row of AR
s.SubMatrix(AR, 0, 1, 1, rc-1)
d.SubMatrix(AL, index, colno+1, 1, rc-1)
blasd.Swap(&s, &d)
// S2 -- D2
s.SubMatrix(AL, index+1, colno, lr-index-2, 1)
d.SubMatrix(AL, index, index+1, 1, colno-index-1)
blasd.Swap(&s, &d)
// S3 -- D3
s.SubMatrix(AL, 0, index, index, 1)
d.SubMatrix(AL, 0, colno, index, 1)
blasd.Swap(&s, &d)
//fmt.Printf("3, AR=%v\n", AR)
// swap P1 and P3
p1 := AR.Get(0, 0)
p3 := AL.Get(index, index)
AR.Set(0, 0, p3)
AL.Set(index, index, p1)
return
}
}
/*
* Apply diagonal pivot (row and column swapped) to symmetric matrix blocks.
* AR[0,0] is on diagonal and AL is block to the left of diagonal and AR the
* triangular diagonal block. Need to swap row and column.
*
* LOWER triangular; moving from top-left to bottom-right
*
* d
* x d |
* --------------------------
* x x | d
* S1 S1| S1 P1 x x x P2 -- current row/col 'srcix'
* x x | x S2 d x x x
* x x | x S2 x d x x
* x x | x S2 x x d x
* D1 D1| D1 P2 D2 D2 D2 P3 -- swap with row/col 'dstix'
* x x | x S3 x x x D3 d
* x x | x S3 x x x D3 x d
* (ABL) (ABR)
*
* UPPER triangular; moving from bottom-right to top-left
*
* (ATL) (ATR)
* d x x D3 x x x S3 x | x
* d x D3 x x x S3 x | x
* d D3 x x x S3 x | x
* P3 D2 D2 D2 P2 D1| D1 -- dstinx
* d x x S2 x | x
* d x S2 x | x
* d S2 x | x
* P1 S1| S1 -- srcinx
* d | x
* -----------------------------
* | d
* (ABR)
*/
func applyPivotSym2(AL, AR *cmat.FloatMatrix, srcix, dstix int, flags int) {
var s, d cmat.FloatMatrix
_, lc := AL.Size()
rr, rc := AR.Size()
if flags&gomas.LOWER != 0 {
// AL is [ABL]; AR is [ABR]; P1 is AR[0,0], P2 is AR[index, 0]
// S1 -- D1
AL.SubMatrix(&s, srcix, 0, 1, lc)
AL.SubMatrix(&d, dstix, 0, 1, lc)
blasd.Swap(&s, &d)
if srcix > 0 {
AR.SubMatrix(&s, srcix, 0, 1, srcix)
AR.SubMatrix(&d, dstix, 0, 1, srcix)
blasd.Swap(&s, &d)
}
// S2 -- D2
AR.SubMatrix(&s, srcix+1, srcix, dstix-srcix-1, 1)
AR.SubMatrix(&d, dstix, srcix+1, 1, dstix-srcix-1)
blasd.Swap(&s, &d)
// S3 -- D3
AR.SubMatrix(&s, dstix+1, srcix, rr-dstix-1, 1)
AR.SubMatrix(&d, dstix+1, dstix, rr-dstix-1, 1)
blasd.Swap(&s, &d)
// swap P1 and P3
p1 := AR.Get(srcix, srcix)
p3 := AR.Get(dstix, dstix)
AR.Set(srcix, srcix, p3)
AR.Set(dstix, dstix, p1)
return
}
if flags&gomas.UPPER != 0 {
// AL is ATL, AR is ATR; P1 is AL[srcix, srcix];
// S1 -- D1;
AR.SubMatrix(&s, srcix, 0, 1, rc)
AR.SubMatrix(&d, dstix, 0, 1, rc)
blasd.Swap(&s, &d)
if srcix < lc-1 {
// not the corner element
AL.SubMatrix(&s, srcix, srcix+1, 1, srcix)
AL.SubMatrix(&d, dstix, srcix+1, 1, srcix)
blasd.Swap(&s, &d)
}
// S2 -- D2
AL.SubMatrix(&s, dstix+1, srcix, srcix-dstix-1, 1)
AL.SubMatrix(&d, dstix, dstix+1, 1, srcix-dstix-1)
blasd.Swap(&s, &d)
// S3 -- D3
AL.SubMatrix(&s, 0, srcix, dstix, 1)
AL.SubMatrix(&d, 0, dstix, dstix, 1)
blasd.Swap(&s, &d)
//fmt.Printf("3, AR=%v\n", AR)
// swap P1 and P3
p1 := AR.Get(0, 0)
p3 := AL.Get(dstix, dstix)
AR.Set(srcix, srcix, p3)
AL.Set(dstix, dstix, p1)
return
}
}
func trdsecEigenBuildInplace(Q, z *cmat.FloatMatrix) {
var QTL, QBR, Q00, q11, q12, q21, Q22, qi cmat.FloatMatrix
var zk0, zk1, dk0, dk1 float64
util.Partition2x2(
&QTL, nil,
nil, &QBR /**/, Q, 0, 0, util.PTOPLEFT)
for m(&QBR) > 0 {
util.Repartition2x2to3x3(&QTL,
&Q00, nil, nil,
nil, &q11, &q12,
nil, &q21, &Q22 /**/, Q, 1, util.PBOTTOMRIGHT)
//---------------------------------------------------------------
k := m(&Q00)
zk0 = z.GetAt(k)
dk0 = q11.Get(0, 0)
q11.Set(0, 0, zk0/dk0)
for i := 0; i < q12.Len(); i++ {
zk1 = z.GetAt(k + i + 1)
dk0 = q12.GetAt(i)
dk1 = q21.GetAt(i)
q12.SetAt(i, zk0/dk1)
q21.SetAt(i, zk1/dk0)
}
//---------------------------------------------------------------
util.Continue3x3to2x2(
&QTL, nil,
nil, &QBR /**/, &Q00, &q11, &Q22 /**/, Q, util.PBOTTOMRIGHT)
}
// scale column eigenvectors
for k := 0; k < z.Len(); k++ {
qi.Column(Q, k)
t := blasd.Nrm2(&qi)
blasd.InvScale(&qi, t)
}
}
func unblockedLowerCHOL(A *cmat.FloatMatrix, flags int, nr int) (err *gomas.Error) {
var ATL, ATR, ABL, ABR cmat.FloatMatrix
var A00, a10, a11, A20, a21, A22 cmat.FloatMatrix
err = nil
util.Partition2x2(
&ATL, &ATR,
&ABL, &ABR, A, 0, 0, util.PTOPLEFT)
for m(&ATL) < m(A) {
util.Repartition2x2to3x3(&ATL,
&A00, nil, nil,
&a10, &a11, nil,
&A20, &a21, &A22, A, 1, util.PBOTTOMRIGHT)
// a11 = sqrt(a11)
aval := a11.Get(0, 0)
if aval < 0.0 {
if err == nil {
err = gomas.NewError(gomas.ENEGATIVE, "DecomposeCHOL", m(&ATL)+nr)
}
} else {
a11.Set(0, 0, math.Sqrt(aval))
}
// a21 = a21/a11
blasd.InvScale(&a21, a11.Get(0, 0))
// A22 = A22 - a21*a21' (SYR)
blasd.MVUpdateSym(&A22, &a21, -1.0, gomas.LOWER)
util.Continue3x3to2x2(
&ATL, &ATR,
&ABL, &ABR, &A00, &a11, &A22, A, util.PBOTTOMRIGHT)
}
return
}
/* From LAPACK/dlarfg.f
*
* Generates a real elementary reflector H of order n, such
* that
*
* H * ( alpha ) = ( beta ), H**T * H = I.
* ( x ) ( 0 )
*
* where alpha and beta are scalars, and x is an (n-1)-element real
* vector. H is represented in the form
*
* H = I - tau * ( 1 ) * ( 1 v**T ) ,
* ( v )
*
* where tau is a real scalar and v is a real (n-1)-element
* vector.
*
* If the elements of x are all zero, then tau = 0 and H is taken to be
* the unit cmat.
*
* Otherwise 1 <= tau <= 2.
*/
func computeHouseholder(a11, x, tau *cmat.FloatMatrix) {
// norm_x2 = ||x||_2
norm_x2 := blasd.Nrm2(x)
if norm_x2 == 0.0 {
tau.Set(0, 0, 0.0)
return
}
alpha := a11.Get(0, 0)
sign := 1.0
if math.Signbit(alpha) {
sign = -1.0
}
// beta = -(alpha / |alpha|) * ||alpha x||
// = -sign(alpha) * sqrt(alpha**2, norm_x2**2)
beta := -sign * sqrtX2Y2(alpha, norm_x2)
// x = x /(a11 - beta)
blasd.InvScale(x, alpha-beta)
tau.Set(0, 0, (beta-alpha)/beta)
a11.Set(0, 0, beta)
}
/*
* Computes upper Hessenberg reduction of N-by-N matrix A using unblocked
* algorithm as described in (1).
*
* Hessengerg reduction: A = Q.T*B*Q, Q unitary, B upper Hessenberg
* Q = H(0)*H(1)*...*H(k) where H(k) is k'th Householder reflector.
*
* Compatible with lapack.DGEHD2.
*/
func unblkHessGQvdG(A, Tvec, W *cmat.FloatMatrix, row int) {
var ATL, ATR, ABL, ABR cmat.FloatMatrix
var A00, a11, a21, A22 cmat.FloatMatrix
var AL, AR, A0, a1, A2 cmat.FloatMatrix
var tT, tB cmat.FloatMatrix
var t0, tau1, t2, w12, v1 cmat.FloatMatrix
util.Partition2x2(
&ATL, &ATR,
&ABL, &ABR, A, row, 0, util.PTOPLEFT)
util.Partition1x2(
&AL, &AR, A, 0, util.PLEFT)
util.Partition2x1(
&tT,
&tB, Tvec, 0, util.PTOP)
v1.SubMatrix(W, 0, 0, m(A), 1)
for m(&ABR) > 1 && n(&ABR) > 0 {
util.Repartition2x2to3x3(&ATL,
&A00, nil, nil,
nil, &a11, nil,
nil, &a21, &A22, A, 1, util.PBOTTOMRIGHT)
util.Repartition1x2to1x3(&AL,
&A0, &a1, &A2, A, 1, util.PRIGHT)
util.Repartition2x1to3x1(&tT,
&t0,
&tau1,
&t2, Tvec, 1, util.PBOTTOM)
// ------------------------------------------------------
// a21 = [beta; H(k)].T
computeHouseholderVec(&a21, &tau1)
tauval := tau1.Get(0, 0)
beta := a21.Get(0, 0)
a21.Set(0, 0, 1.0)
// v1 := A2*a21
blasd.MVMult(&v1, &A2, &a21, 1.0, 0.0, gomas.NONE)
// A2 := A2 - tau*v1*a21 (A2 := A2*H(k))
blasd.MVUpdate(&A2, &v1, &a21, -tauval)
w12.SubMatrix(W, 0, 0, n(&A22), 1)
// w12 := a21.T*A22 = A22.T*a21
blasd.MVMult(&w12, &A22, &a21, 1.0, 0.0, gomas.TRANS)
// A22 := A22 - tau*a21*w12 (A22 := H(k)*A22)
blasd.MVUpdate(&A22, &a21, &w12, -tauval)
a21.Set(0, 0, beta)
// ------------------------------------------------------
util.Continue3x3to2x2(
&ATL, &ATR,
&ABL, &ABR, &A00, &a11, &A22, A, util.PBOTTOMRIGHT)
util.Continue1x3to1x2(
&AL, &AR, &A0, &a1, A, util.PRIGHT)
util.Continue3x1to2x1(
&tT,
&tB, &t0, &tau1, Tvec, util.PBOTTOM)
}
}
/*
* Blocked version of Hessenberg reduction algorithm as presented in (1). This
* version uses compact-WY transformation.
*
* Some notes:
*
* Elementary reflectors stored in [A11; A21].T are not on diagonal of A11. Update of
* a block aligned with A11; A21 is as follow
*
* 1. Update from left Q(k)*C:
* c0 0 c0
* (I - Y*T*Y.T).T*C = C - Y*(C.T*Y)*T.T = C1 - Y1 * (C1.T.Y1+C2.T*Y2)*T.T = C1-Y1*W
* C2 Y2 C2-Y2*W
*
* where W = (C1.T*Y1+C2.T*Y2)*T.T and first row of C is not affected by update
*
* 2. Update from right C*Q(k):
* 0
* C - C*Y*T*Y.T = c0;C1;C2 - c0;C1;C2 * Y1 *T*(0;Y1;Y2) = c0; C1-W*Y1; C2-W*Y2
* Y2
* where W = (C1*Y1 + C2*Y2)*T and first column of C is not affected
*
*/
func blkHessGQvdG(A, Tvec, W *cmat.FloatMatrix, nb int, conf *gomas.Config) *gomas.Error {
var ATL, ATR, ABL, ABR cmat.FloatMatrix
var A00, A11, A12, A21, A22, A2 cmat.FloatMatrix
var tT, tB, td cmat.FloatMatrix
var t0, t1, t2, T cmat.FloatMatrix
var V, VT, VB /*V0, V1, V2,*/, Y1, Y2, W0 cmat.FloatMatrix
//fmt.Printf("blkHessGQvdG...\n")
T.SubMatrix(W, 0, 0, conf.LB, conf.LB)
V.SubMatrix(W, conf.LB, 0, m(A), conf.LB)
td.Diag(&T)
util.Partition2x2(
&ATL, &ATR,
&ABL, &ABR, A, 0, 0, util.PTOPLEFT)
util.Partition2x1(
&tT,
&tB, Tvec, 0, util.PTOP)
for m(&ABR) > nb+1 && n(&ABR) > nb {
util.Repartition2x2to3x3(&ATL,
&A00, nil, nil,
nil, &A11, &A12,
nil, &A21, &A22, A, nb, util.PBOTTOMRIGHT)
util.Repartition2x1to3x1(&tT,
&t0,
&t1,
&t2, Tvec, nb, util.PBOTTOM)
util.Partition2x1(
&VT,
&VB, &V, m(&ATL), util.PTOP)
// ------------------------------------------------------
unblkBuildHessGQvdG(&ABR, &T, &VB, nil)
blasd.Copy(&t1, &td)
// m(Y) == m(ABR)-1, n(Y) == n(A11)
Y1.SubMatrix(&ABR, 1, 0, n(&A11), n(&A11))
Y2.SubMatrix(&ABR, 1+n(&A11), 0, m(&A21)-1, n(&A11))
// [A01; A02] == ATR := ATR*(I - Y*T*Y.T)
updateHessRightWY(&ATR, &Y1, &Y2, &T, &VT, conf)
// A2 = [A12; A22].T
util.Merge2x1(&A2, &A12, &A22)
// A2 := A2 - VB*T*A21.T
be := A21.Get(0, -1)
A21.Set(0, -1, 1.0)
blasd.MultTrm(&VB, &T, 1.0, gomas.UPPER|gomas.RIGHT)
blasd.Mult(&A2, &VB, &A21, -1.0, 1.0, gomas.TRANSB, conf)
A21.Set(0, -1, be)
// A2 := (I - Y*T*Y.T).T * A2
W0.SubMatrix(&V, 0, 0, n(&A2), n(&Y2))
updateHessLeftWY(&A2, &Y1, &Y2, &T, &W0, conf)
// ------------------------------------------------------
util.Continue3x3to2x2(
&ATL, &ATR,
&ABL, &ABR, &A00, &A11, &A22, A, util.PBOTTOMRIGHT)
util.Continue3x1to2x1(
&tT,
&tB, &t0, &t1, Tvec, util.PBOTTOM)
}
if m(&ABR) > 1 {
// do the rest with unblocked
util.Merge2x1(&A2, &ATR, &ABR)
W0.SetBuf(m(A), 1, m(A), W.Data())
unblkHessGQvdG(&A2, &tB, &W0, m(&ATR))
}
return nil
}
/*
*
* Building reduction block for blocked algorithm as described in (1).
*
* A. update next column
* a10 [(U00) (U00) ] [(a10) (V00) ]
* a11 := I -[(u10)*T00*(u10).T] * [(a11) - (v01) * T00 * a10]
* a12 [(U20) (U20) ] [(a12) (V02) ]
*
* B. compute Householder reflector for updated column
* a21, t11 := Householder(a21)
*
* C. update intermediate reductions
* v10 A02*a21
* v11 := a12*a21
* v12 A22*a21
*
* D. update block reflector
* t01 := A20*a21
* t11 := t11
*/
func unblkBuildHessGQvdG(A, T, V, W *cmat.FloatMatrix) *gomas.Error {
var ATL, ATR, ABL, ABR cmat.FloatMatrix
var A00, a10, a11, A20, a21, A22 cmat.FloatMatrix
var AL, AR, A0, a1, A2 cmat.FloatMatrix
var TTL, TTR, TBL, TBR cmat.FloatMatrix
var T00, t01, t11, T22 cmat.FloatMatrix
var VL, VR, V0, v1, V2, Y0 cmat.FloatMatrix
util.Partition2x2(
&ATL, &ATR,
&ABL, &ABR, A, 0, 0, util.PTOPLEFT)
util.Partition2x2(
&TTL, &TTR,
&TBL, &TBR, T, 0, 0, util.PTOPLEFT)
util.Partition1x2(
&AL, &AR, A, 0, util.PLEFT)
util.Partition1x2(
&VL, &VR, V, 0, util.PLEFT)
var beta float64
for n(&VR) > 0 {
util.Repartition2x2to3x3(&ATL,
&A00, nil, nil,
&a10, &a11, nil,
&A20, &a21, &A22, A, 1, util.PBOTTOMRIGHT)
util.Repartition2x2to3x3(&TTL,
&T00, &t01, nil,
nil, &t11, nil,
nil, nil, &T22, T, 1, util.PBOTTOMRIGHT)
util.Repartition1x2to1x3(&AL,
&A0, &a1, &A2, A, 1, util.PRIGHT)
util.Repartition1x2to1x3(&VL,
&V0, &v1, &V2, V, 1, util.PRIGHT)
// ------------------------------------------------------
// Compute Hessenberg update for next column of A:
if n(&V0) > 0 {
// y10 := T00*a10 (use t01 as workspace?)
blasd.Axpby(&t01, &a10, 1.0, 0.0)
blasd.MVMultTrm(&t01, &T00, 1.0, gomas.UPPER)
// a1 := a1 - V0*T00*a10
blasd.MVMult(&a1, &V0, &t01, -1.0, 1.0, gomas.NONE)
// update a1 := (I - Y*T*Y.T).T*a1 (here t01 as workspace)
Y0.SubMatrix(A, 1, 0, n(&A00), n(&A00))
updateVecLeftWY2(&a1, &Y0, &A20, &T00, &t01, gomas.TRANS)
a10.Set(0, -1, beta)
}
// Compute Householder reflector
computeHouseholderVec(&a21, &t11)
beta = a21.Get(0, 0)
a21.Set(0, 0, 1.0)
// v1 := A2*a21
blasd.MVMult(&v1, &A2, &a21, 1.0, 0.0, gomas.NONE)
// update T
tauval := t11.Get(0, 0)
if tauval != 0.0 {
// t01 := -tauval*A20.T*a21
blasd.MVMult(&t01, &A20, &a21, -tauval, 0.0, gomas.TRANS)
// t01 := T00*t01
blasd.MVMultTrm(&t01, &T00, 1.0, gomas.UPPER)
}
// ------------------------------------------------------
util.Continue3x3to2x2(
&ATL, &ATR,
&ABL, &ABR, &A00, &a11, &A22, A, util.PBOTTOMRIGHT)
util.Continue3x3to2x2(
&TTL, &TTR,
&TBL, &TBR, &T00, &t11, &T22, T, util.PBOTTOMRIGHT)
util.Continue1x3to1x2(
&AL, &AR, &A0, &a1, A, util.PRIGHT)
util.Continue1x3to1x2(
&VL, &VR, &V0, &v1, V, util.PRIGHT)
}
A.Set(n(V), n(V)-1, beta)
return nil
}
func unblkBoundedBKUpper(A, wrk *cmat.FloatMatrix, p *Pivots, ncol int, conf *gomas.Config) (*gomas.Error, int) {
var err *gomas.Error = nil
var ATL, ATR, ABL, ABR cmat.FloatMatrix
var A00, a01, A02, a11, a12, A22, a11inv cmat.FloatMatrix
var w00, w01, w11 cmat.FloatMatrix
var cwrk cmat.FloatMatrix
var pT, pB, p0, p1, p2 Pivots
err = nil
nc := 0
if ncol > n(A) {
ncol = n(A)
}
// permanent working space for symmetric inverse of a11
a11inv.SubMatrix(wrk, m(wrk)-2, 0, 2, 2)
a11inv.Set(0, 1, -1.0)
a11inv.Set(1, 0, -1.0)
util.Partition2x2(
&ATL, &ATR,
&ABL, &ABR, A, 0, 0, util.PBOTTOMRIGHT)
partitionPivot2x1(
&pT,
&pB, *p, 0, util.PBOTTOM)
for n(&ATL) > 0 && nc < ncol {
util.Partition2x2(
&w00, &w01,
nil, &w11, wrk, nc, nc, util.PBOTTOMRIGHT)
r, np := findAndBuildBKPivotUpper(&ATL, &ATR, &w00, &w01, nc)
if np > ncol-nc {
// next pivot does not fit into ncol columns,
// return with number of factorized columns
return err, nc
}
cwrk.SubMatrix(&w00, 0, n(&w00)-np, m(&ATL), np)
if r != -1 {
// pivoting needed; do swaping here
k := m(&ATL) - np
applyBKPivotSymUpper(&ATL, k, r)
// swap right hand rows to get correct updates
swapRows(&ATR, k, r)
swapRows(&w01, k, r)
if np == 2 && r != k {
/* for 2x2 blocks we need diagonal pivots.
* [r, r] | [ r,-1]
* a11 == ---------------- 2-by-2 pivot, swapping [1,0] and [r,0]
* [-1,r] | [-1,-1]
*/
t0 := w00.Get(k, -1)
tr := w00.Get(r, -1)
w00.Set(k, -1, tr)
w00.Set(r, -1, t0)
t0 = w00.Get(k, -2)
tr = w00.Get(r, -2)
w00.Set(k, -2, tr)
w00.Set(r, -2, t0)
}
}
// repartition according the pivot size
util.Repartition2x2to3x3(&ATL,
&A00, &a01, &A02,
nil, &a11, &a12,
nil, nil, &A22 /**/, A, np, util.PTOPLEFT)
repartPivot2x1to3x1(&pT,
&p0,
&p1,
&p2 /**/, *p, np, util.PTOP)
// ------------------------------------------------------------
wlc := n(&w00) - np
cwrk.SubMatrix(&w00, 0, wlc, m(&a01), n(&a01))
if np == 1 {
//
a11.Set(0, 0, w00.Get(m(&a01), wlc))
// a21 = a21/a11
blasd.Copy(&a01, &cwrk)
blasd.InvScale(&a01, a11.Get(0, 0))
// store pivot point relative to original matrix
if r == -1 {
p1[0] = m(&ATL)
} else {
p1[0] = r + 1
}
} else if np == 2 {
/* a | b d/b | -1
* w00 == ------ == a11 --> a11.-1 == -------- * scale
* . | d -1 | a/b
*/
a := w00.Get(m(&ATL)-2, -2)
b := w00.Get(m(&ATL)-2, -1)
d := w00.Get(m(&ATL)-1, -1)
a11inv.Set(0, 0, d/b)
a11inv.Set(1, 1, a/b)
// denominator: (a/b)*(d/b)-1.0 == (a*d - b^2)/b^2
scale := 1.0 / ((a/b)*(d/b) - 1.0)
scale /= b
// a01 = a01*a11.-1
blasd.Mult(&a01, &cwrk, &a11inv, scale, 0.0, gomas.NONE, conf)
a11.Set(0, 0, a)
a11.Set(0, 1, b)
a11.Set(1, 1, d)
// store pivot point relative to original matrix
p1[0] = -(r + 1)
p1[1] = p1[0]
}
// ------------------------------------------------------------
nc += np
util.Continue3x3to2x2(
&ATL, &ATR,
&ABL, &ABR, &A00, &a11, &A22, A, util.PTOPLEFT)
contPivot3x1to2x1(
&pT,
&pB, p0, p1, *p, util.PTOP)
}
return err, nc
}
/*
* Multiply and replace C with Q*C or Q.T*C where Q is a real orthogonal matrix
* defined as the product of k elementary reflectors.
*
* Q = H(0)H(1)...H(K-1)
*
* as returned by RQFactor().
*
* Arguments:
* C On entry, the M-by-N matrix C or if flag bit RIGHT is set then
* N-by-M matrix. On exit C is overwritten by Q*C or Q.T*C.
* If bit RIGHT is set then C is overwritten by C*Q or C*Q.T
*
* A RQ factorization as returned by RQFactor() where the upper
* trapezoidal part holds the elementary reflectors.
*
* tau The scalar factors of the elementary reflectors.
*
* W Workspace matrix, required size is returned by RQMultWork().
*
* flags Indicators. Valid indicators LEFT, RIGHT, TRANS
*
* conf Blocking configuration. Field LB defines block sized. If it is zero
* unblocked invocation is assumed.
*
* Compatible with lapack.DORMRQ
*
* Notes:
* m(A) is number of elementary reflectors
* n(A) is the order of the Q matrix
*
* LEFT : m(C) >= n(Q) --> m(A) <= n(C) <= n(A)
* RIGHT: n(C) >= m(Q) --> m(A) <= m(C) <= n(A)
*/
func RQMult(C, A, tau, W *cmat.FloatMatrix, flags int, confs ...*gomas.Config) *gomas.Error {
var err *gomas.Error = nil
var wsmin int
var tauval float64
var Qh, tauh cmat.FloatMatrix
conf := gomas.CurrentConf(confs...)
// default to multiply from left if side not defined
if flags&(gomas.LEFT|gomas.RIGHT) == 0 {
flags = flags | gomas.LEFT
}
// m(A) is number of elementary reflectors, Q is n(A)-by-n(A) matrix
ok := false
lb := 0
hr, hc := m(A), n(A)
switch flags & gomas.RIGHT {
case gomas.RIGHT:
ok = n(C) <= n(A) && m(A) <= n(C)
wsmin = wsMultRQRight(C, 0)
hc = n(C)
lb = estimateLB(C, W.Len(), wsMultRQRight)
default:
ok = m(C) <= n(A) && m(A) <= m(C)
wsmin = wsMultRQLeft(C, 0)
hc = m(C)
lb = estimateLB(C, W.Len(), wsMultRQLeft)
}
if !ok {
return gomas.NewError(gomas.ESIZE, "MultRQ")
}
if W == nil || W.Len() < wsmin {
return gomas.NewError(gomas.EWORK, "MultRQ", wsmin)
}
lb = imin(lb, conf.LB)
Qh.SubMatrix(A, 0, 0, hr, hc)
tauh.SubMatrix(tau, 0, 0, m(A), 1)
if hc == hr {
// m-by-m multiplication, H(K) is unit vector
// set last tauval to zero, householder functions expect this
tauval = tau.Get(hc-1, 0)
tau.Set(hc-1, 0, 0.0)
}
if lb == 0 || m(A) <= lb {
if flags&gomas.RIGHT != 0 {
unblockedMultRQRight(C, &Qh, &tauh, W, flags)
} else {
unblockedMultRQLeft(C, &Qh, &tauh, W, flags)
}
} else {
//lb = conf.LB
if flags&gomas.RIGHT != 0 {
blockedMultRQRight(C, &Qh, &tauh, W, flags, lb, conf)
} else {
blockedMultRQLeft(C, &Qh, &tauh, W, flags, lb, conf)
}
}
if hc == hr {
// restore tau value
tau.Set(hc-1, 0, tauval)
}
return err
}
/*
* 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)
}
/*
* Unblocked Bunch-Kauffman LDL factorization.
*
* Corresponds lapack.DSYTF2
*/
func unblkDecompBKUpper(A, wrk *cmat.FloatMatrix, p Pivots, conf *gomas.Config) (*gomas.Error, int) {
var err *gomas.Error = nil
var ATL, ATR, ABL, ABR cmat.FloatMatrix
var A00, a01, A02, a11, a12, A22, a11inv cmat.FloatMatrix
var cwrk cmat.FloatMatrix
var pT, pB, p0, p1, p2 Pivots
err = nil
nc := 0
util.Partition2x2(
&ATL, &ATR,
&ABL, &ABR, A, 0, 0, util.PBOTTOMRIGHT)
partitionPivot2x1(
&pT,
&pB, p, 0, util.PBOTTOM)
// permanent working space for symmetric inverse of a11
a11inv.SubMatrix(wrk, 0, n(wrk)-2, 2, 2)
a11inv.Set(1, 0, -1.0)
a11inv.Set(0, 1, -1.0)
for n(&ATL) > 0 {
nr := m(&ATL) - 1
r, np := findBKPivotUpper(&ATL)
if r != -1 {
cwrk.SubMatrix(&ATL, 0, n(&ATL)-np, m(&ATL), np)
// pivoting needed; do swaping here
applyBKPivotSymUpper(&ATL, m(&ATL)-np, r)
if np == 2 {
/* [r, r] | [r, nr]
* a11 == ---------------- 2-by-2 pivot, swapping [nr-1,nr] and [r,nr]
* [nr,r] | [nr,nr] (nr is the current diagonal entry)
*/
t := ATL.Get(nr-1, nr)
ATL.Set(nr-1, nr, ATL.Get(r, nr))
ATL.Set(r, nr, t)
}
}
// repartition according the pivot size
util.Repartition2x2to3x3(&ATL,
&A00, &a01, &A02,
nil, &a11, &a12,
nil, nil, &A22 /**/, A, np, util.PTOPLEFT)
repartPivot2x1to3x1(&pT,
&p0,
&p1,
&p2 /**/, p, np, util.PTOP)
// ------------------------------------------------------------
if np == 1 {
// A00 = A00 - a01*a01.T/a11
blasd.MVUpdateTrm(&A00, &a01, &a01, -1.0/a11.Get(0, 0), gomas.UPPER)
// a01 = a01/a11
blasd.InvScale(&a01, a11.Get(0, 0))
// store pivot point relative to original matrix
if r == -1 {
p1[0] = m(&ATL)
} else {
p1[0] = r + 1
}
} else if np == 2 {
/* see comments on unblkDecompBKLower() */
a := a11.Get(0, 0)
b := a11.Get(0, 1)
d := a11.Get(1, 1)
a11inv.Set(0, 0, d/b)
a11inv.Set(1, 1, a/b)
// denominator: (a/b)*(d/b)-1.0 == (a*d - b^2)/b^2
scale := 1.0 / ((a/b)*(d/b) - 1.0)
scale /= b
// cwrk = a21
cwrk.SubMatrix(wrk, 2, 0, m(&a01), n(&a01))
blasd.Copy(&cwrk, &a01)
// a01 = a01*a11.-1
blasd.Mult(&a01, &cwrk, &a11inv, scale, 0.0, gomas.NONE, conf)
// A00 = A00 - a01*a11.-1*a01.T = A00 - a01*cwrk.T
blasd.UpdateTrm(&A00, &a01, &cwrk, -1.0, 1.0, gomas.UPPER|gomas.TRANSB, conf)
// store pivot point relative to original matrix
p1[0] = -(r + 1)
p1[1] = p1[0]
}
// ------------------------------------------------------------
nc += np
util.Continue3x3to2x2(
&ATL, &ATR,
&ABL, &ABR, &A00, &a11, &A22, A, util.PTOPLEFT)
contPivot3x1to2x1(
&pT,
&pB, p0, p1, p, util.PTOP)
}
return err, nc
}
/*
* Unblocked solve A*X = B for Bunch-Kauffman factorized symmetric real matrix.
*/
func unblkSolveBKUpper(B, A *cmat.FloatMatrix, p Pivots, phase int, conf *gomas.Config) *gomas.Error {
var err *gomas.Error = nil
var ATL, ATR, ABL, ABR cmat.FloatMatrix
var A00, a01, A02, a11, a12t, A22 cmat.FloatMatrix
var Aref *cmat.FloatMatrix
var BT, BB, B0, b1, B2, Bx cmat.FloatMatrix
var pT, pB, p0, p1, p2 Pivots
var aStart, aDir, bStart, bDir util.Direction
var nc int
np := 0
if phase == 2 {
aStart = util.PTOPLEFT
aDir = util.PBOTTOMRIGHT
bStart = util.PTOP
bDir = util.PBOTTOM
nc = 1
Aref = &ABR
} else {
aStart = util.PBOTTOMRIGHT
aDir = util.PTOPLEFT
bStart = util.PBOTTOM
bDir = util.PTOP
nc = m(A)
Aref = &ATL
}
util.Partition2x2(
&ATL, &ATR,
&ABL, &ABR, A, 0, 0, aStart)
util.Partition2x1(
&BT,
&BB, B, 0, bStart)
partitionPivot2x1(
&pT,
&pB, p, 0, bStart)
// phase 1:
// - solve U*D*X = B, overwriting B with X
// - looping from BOTTOM to TOP
// phase 1:
// - solve U*X = B, overwriting B with X
// - looping from TOP to BOTTOM
for n(Aref) > 0 {
// see if next diagonal block is 1x1 or 2x2
np = 1
if p[nc-1] < 0 {
np = 2
}
// repartition according the pivot size
util.Repartition2x2to3x3(&ATL,
&A00, &a01, &A02,
nil, &a11, &a12t,
nil, nil, &A22 /**/, A, np, aDir)
util.Repartition2x1to3x1(&BT,
&B0,
&b1,
&B2 /**/, B, np, bDir)
repartPivot2x1to3x1(&pT,
&p0,
&p1,
&p2 /**/, p, np, bDir)
// ------------------------------------------------------------
switch phase {
case 1:
// computes D.-1*(U.-1*B);
// b1 is current row, last row of BT
if np == 1 {
if p1[0] != nc {
// swap rows on top part of B
swapRows(&BT, m(&BT)-1, p1[0]-1)
}
// B0 = B0 - a01*b1
blasd.MVUpdate(&B0, &a01, &b1, -1.0)
// b1 = b1/d1
blasd.InvScale(&b1, a11.Get(0, 0))
nc -= 1
} else if np == 2 {
if p1[0] != -nc {
// swap rows on top part of B
swapRows(&BT, m(&BT)-2, -p1[0]-1)
}
b := a11.Get(0, 1)
apb := a11.Get(0, 0) / b
dpb := a11.Get(1, 1) / b
// (a/b)*(d/b)-1.0 == (a*d - b^2)/b^2
scale := apb*dpb - 1.0
scale *= b
// B0 = B0 - a01*b1
blasd.Mult(&B0, &a01, &b1, -1.0, 1.0, gomas.NONE, conf)
// b1 = a11.-1*b1.T
//(2x2 block, no subroutine for doing this in-place)
for k := 0; k < n(&b1); k++ {
s0 := b1.Get(0, k)
s1 := b1.Get(1, k)
b1.Set(0, k, (dpb*s0-s1)/scale)
b1.Set(1, k, (apb*s1-s0)/scale)
}
nc -= 2
}
case 2:
// compute X = U.-T*B
if np == 1 {
blasd.MVMult(&b1, &B0, &a01, -1.0, 1.0, gomas.TRANS)
if p1[0] != nc {
// swap rows on bottom part of B
util.Merge2x1(&Bx, &B0, &b1)
swapRows(&Bx, m(&Bx)-1, p1[0]-1)
}
nc += 1
} else if np == 2 {
blasd.Mult(&b1, &a01, &B0, -1.0, 1.0, gomas.TRANSA, conf)
if p1[0] != -nc {
// swap rows on bottom part of B
util.Merge2x1(&Bx, &B0, &b1)
swapRows(&Bx, m(&Bx)-2, -p1[0]-1)
}
nc += 2
}
}
// ------------------------------------------------------------
util.Continue3x3to2x2(
&ATL, &ATR,
&ABL, &ABR, &A00, &a11, &A22, A, aDir)
util.Continue3x1to2x1(
&BT,
&BB, &B0, &b1, B, bDir)
contPivot3x1to2x1(
&pT,
&pB, p0, p1, p, bDir)
}
return err
}
/*
* 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)
}
/*
* Find diagonal pivot and build incrementaly updated block.
*
* d x r2 x x x c1 | x x kp1 k | w w
* d r2 x x x c1 | x x kp1 k | w w
* r2 r2 r2 r2 c1 | x x kp1 k | w w
* d x x c1 | x x kp1 k | w w
* d x c1 | x x kp1 k | w w
* d c1 | x x kp1 k | w w
* c1 | x x kp1 k | w w
* -------------------------- -------------
* (AL) (AR) (WL) (WR)
*
* Matrix AL contains the unfactored part of the matrix and AR the already
* factored columns. Matrix WR is updated values of factored part ie.
* w(i) = l(i)d(i). Matrix WL will have updated values for next column.
* Column WL(k) contains updated AL(c1) and WL(kp1) possible pivot row AL(r2).
*
* On exit, for 1x1 diagonal the rightmost column of WL (k) holds the updated
* value of AL(c1). If pivoting this required the WL(k) holds the actual pivoted
* column/row.
*
* For 2x2 diagonal blocks WL(k) holds the updated AL(c1) and WL(kp1) holds
* actual values of pivot column/row AL(r2), without the diagonal pivots.
*/
func findAndBuildBKPivotUpper(AL, AR, WL, WR *cmat.FloatMatrix, k int) (int, int) {
var r, q int
var rcol, qrow, src, wk, wkp1, wrow cmat.FloatMatrix
lc := n(AL) - 1
wc := n(WL) - 1
lr := m(AL) - 1
// Copy AL[:,lc] to WL[:,wc] and update with WR[0:]
src.SubMatrix(AL, 0, lc, m(AL), 1)
wk.SubMatrix(WL, 0, wc, m(AL), 1)
blasd.Copy(&wk, &src)
if k > 0 {
wrow.SubMatrix(WR, lr, 0, 1, n(WR))
blasd.MVMult(&wk, AR, &wrow, -1.0, 1.0, gomas.NONE)
}
if m(AL) == 1 {
return -1, 1
}
// amax is on-diagonal element of current column
amax := math.Abs(WL.Get(lr, wc))
// find max off-diagonal on first column.
rcol.SubMatrix(WL, 0, wc, lr, 1)
// r is row index and rmax is its absolute value
r = blasd.IAmax(&rcol)
rmax := math.Abs(rcol.Get(r, 0))
if amax >= bkALPHA*rmax {
// no pivoting, 1x1 diagonal
return -1, 1
}
// Now we need to copy row r to WL[:,wc-1] and update it
wkp1.SubMatrix(WL, 0, wc-1, m(AL), 1)
if r > 0 {
// above the diagonal part of AL
qrow.SubMatrix(AL, 0, r, r, 1)
blasd.Copy(&wkp1, &qrow)
}
var wkr cmat.FloatMatrix
qrow.SubMatrix(AL, r, r, 1, m(AL)-r)
wkr.SubMatrix(&wkp1, r, 0, m(AL)-r, 1)
blasd.Copy(&wkr, &qrow)
if k > 0 {
// update wkp1
wrow.SubMatrix(WR, r, 0, 1, n(WR))
blasd.MVMult(&wkp1, AR, &wrow, -1.0, 1.0, gomas.NONE)
}
// set on-diagonal entry to zero to avoid hitting it.
p1 := wkp1.Get(r, 0)
wkp1.Set(r, 0, 0.0)
// max off-diagonal on r'th column/row at index q
q = blasd.IAmax(&wkp1)
qmax := math.Abs(wkp1.Get(q, 0))
wkp1.Set(r, 0, p1)
if amax >= bkALPHA*rmax*(rmax/qmax) {
// no pivoting, 1x1 diagonal
return -1, 1
}
// if q == r then qmax is not off-diagonal, qmax == WR[r,1] and
// we get 1x1 pivot as following is always true
if math.Abs(WL.Get(r, wc-1)) >= bkALPHA*qmax {
// 1x1 pivoting and interchange with k, r
// pivot row in column WL[:,-2] to WL[:,-1]
src.SubMatrix(WL, 0, wc-1, m(AL), 1)
wkp1.SubMatrix(WL, 0, wc, m(AL), 1)
blasd.Copy(&wkp1, &src)
wkp1.Set(-1, 0, src.Get(r, 0))
wkp1.Set(r, 0, src.Get(-1, 0))
return r, 1
} else {
// 2x2 pivoting and interchange with k+1, r
return r, 2
}
return -1, 1
}
