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lapack/{gonum,testlapack}: don't use work in Dlangb

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This commit is contained in:
Vladimir Chalupecky
2021-05-07 11:57:25 +02:00
committed by Vladimír Chalupecký
parent d66e8d4b48
commit f0d77794af
3 changed files with 20 additions and 35 deletions
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28
lapack/gonum/dlangb.go
View File

@@ -13,9 +13,7 @@ import (
// Dlangb returns the given norm of an m×n band matrix with kl sub-diagonals and
// ku super-diagonals.
//
// When norm is lapack.MaxColumnSum, the length of work must be at least n.
func (impl Implementation) Dlangb(norm lapack.MatrixNorm, m, n, kl, ku int, ab []float64, ldab int, work []float64) float64 {
func (impl Implementation) Dlangb(norm lapack.MatrixNorm, m, n, kl, ku int, ab []float64, ldab int) float64 {
ncol := kl + 1 + ku
switch {
case norm != lapack.MaxAbs && norm != lapack.MaxRowSum && norm != lapack.MaxColumnSum && norm != lapack.Frobenius:
@@ -40,8 +38,6 @@ func (impl Implementation) Dlangb(norm lapack.MatrixNorm, m, n, kl, ku int, ab [
switch {
case len(ab) < min(m, n+kl)*ldab:
panic(shortAB)
case len(work) < n && norm == lapack.MaxColumnSum:
panic(shortWork)
}
var value float64
@@ -67,21 +63,13 @@ func (impl Implementation) Dlangb(norm lapack.MatrixNorm, m, n, kl, ku int, ab [
}
}
case lapack.MaxColumnSum:
work = work[:n]
for j := range work {
work[j] = 0
}
for i := 0; i < min(m, n+kl); i++ {
l := max(0, kl-i)
u := min(n+kl-i, ncol)
for jb, aij := range ab[i*ldab+l : i*ldab+u] {
j := l + jb - kl + i
work[j] += math.Abs(aij)
}
}
for _, sumj := range work {
if sumj > value || math.IsNaN(sumj) {
value = sumj
for j := 0; j < min(m+ku, n); j++ {
jb := min(kl+j, ncol-1)
ib := max(0, j-ku)
jlen := min(j+kl, m-1) - ib + 1
sum := f64.L1NormInc(ab[ib*ldab+jb:], jlen, max(1, ldab-1))
if sum > value || math.IsNaN(sum) {
value = sum
}
}
case lapack.Frobenius:

6
lapack/lapack64/lapack64.go
View File

@@ -469,12 +469,10 @@ func Lange(norm lapack.MatrixNorm, a blas64.General, work []float64) float64 {
// Langb returns the given norm of a general m×n band matrix with kl sub-diagonals and
// ku super-diagonals.
//
// When norm is lapack.MaxColumnSum, the length of work must be at least n.
//
// Dlangb is not part of the lapack.Float64 interface and so calls to Langb are always
// executed by the Gonum implementation.
func Langb(norm lapack.MatrixNorm, a blas64.Band, work []float64) float64 {
return gonum.Implementation{}.Dlangb(norm, a.Rows, a.Cols, a.KL, a.KU, a.Data, max(1, a.Stride), work)
func Langb(norm lapack.MatrixNorm, a blas64.Band) float64 {
return gonum.Implementation{}.Dlangb(norm, a.Rows, a.Cols, a.KL, a.KU, a.Data, max(1, a.Stride))
}
// Langt computes the specified norm of an n×n tridiagonal matrix.

19
lapack/testlapack/dlangb.go
View File

@@ -16,7 +16,7 @@ import (
)
type Dlangber interface {
Dlangb(norm lapack.MatrixNorm, m, n, kl, ku int, ab []float64, ldab int, work []float64) float64
Dlangb(norm lapack.MatrixNorm, m, n, kl, ku int, ab []float64, ldab int) float64
}
func DlangbTest(t *testing.T, impl Dlangber) {
@@ -28,14 +28,12 @@ func DlangbTest(t *testing.T, impl Dlangber) {
for _, kl := range []int{0, 1, 2, 3, 4, 5, 10} {
for _, ku := range []int{0, 1, 2, 3, 4, 5, 10} {
for _, ldab := range []int{kl + ku + 1, kl + ku + 1 + 7} {
for iter := 0; iter < 10; iter++ {
dlangbTest(t, impl, rnd, norm, m, n, kl, ku, ldab)
}
}
}
}
}
}
})
}
}
@@ -57,11 +55,11 @@ func dlangbTest(t *testing.T, impl Dlangber, rnd *rand.Rand, norm lapack.MatrixN
// Deal with zero-sized matrices early.
if m == 0 || n == 0 {
got := impl.Dlangb(norm, m, n, kl, ku, nil, ldab, nil)
got := impl.Dlangb(norm, m, n, kl, ku, nil, ldab)
if got != 0 {
t.Errorf("%v: unexpected result for zero-sized matrix with nil input", name)
}
got = impl.Dlangb(norm, m, n, kl, ku, ab, ldab, nil)
got = impl.Dlangb(norm, m, n, kl, ku, ab, ldab)
if !floats.Same(ab, abCopy) {
t.Errorf("%v: unexpected modification in dl", name)
}
@@ -71,11 +69,7 @@ func dlangbTest(t *testing.T, impl Dlangber, rnd *rand.Rand, norm lapack.MatrixN
return
}
var work []float64
if norm == lapack.MaxColumnSum {
work = make([]float64, n)
}
got := impl.Dlangb(norm, m, n, kl, ku, ab, ldab, work)
got := impl.Dlangb(norm, m, n, kl, ku, ab, ldab)
if !floats.Same(ab, abCopy) {
t.Errorf("%v: unexpected modification in ab", name)
@@ -97,6 +91,11 @@ func dlangbTest(t *testing.T, impl Dlangber, rnd *rand.Rand, norm lapack.MatrixN
return
}
if math.IsNaN(got) {
t.Errorf("%v: unexpected NaN; want %v", name, want)
return
}
if norm == lapack.MaxAbs {
if got != want {
t.Errorf("%v: unexpected result; got %v, want %v", name, got, want)