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lapack/gonum: clean up implementation comments in Dpbtf2

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This commit is contained in:
Vladimir Chalupecky
2019-05-27 16:18:18 +02:00
committed by Vladimír Chalupecký
parent 3db45405ae
commit 47d77d149e
1 changed files with 10 additions and 8 deletions
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18
lapack/gonum/dpbtf2.go
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@@ -47,9 +47,9 @@ import (
// version.
//
// Dpbtf2 is an internal routine, exported for testing purposes.
func (Implementation) Dpbtf2(ul blas.Uplo, n, kd int, ab []float64, ldab int) (ok bool) {
func (Implementation) Dpbtf2(uplo blas.Uplo, n, kd int, ab []float64, ldab int) (ok bool) {
switch {
case ul != blas.Upper && ul != blas.Lower:
case uplo != blas.Upper && uplo != blas.Lower:
panic(badUplo)
case n < 0:
panic(nLT0)
@@ -59,6 +59,7 @@ func (Implementation) Dpbtf2(ul blas.Uplo, n, kd int, ab []float64, ldab int) (o
panic(badLdA)
}
// Quick return if possible.
if n == 0 {
return
}
@@ -70,16 +71,17 @@ func (Implementation) Dpbtf2(ul blas.Uplo, n, kd int, ab []float64, ldab int) (o
bi := blas64.Implementation()
kld := max(1, ldab-1)
if ul == blas.Upper {
if uplo == blas.Upper {
// Compute the Cholesky factorization A = U^T * U.
for j := 0; j < n; j++ {
// Compute U(J,J) and test for non positive-definiteness.
// Compute U(j,j) and test for non-positive-definiteness.
ajj := ab[j*ldab]
if ajj <= 0 {
return false
}
ajj = math.Sqrt(ajj)
ab[j*ldab] = ajj
// Compute elements j+1:j+kn of row J and update the trailing submatrix
// Compute elements j+1:j+kn of row j and update the trailing submatrix
// within the band.
kn := min(kd, n-j-1)
if kn > 0 {
@@ -89,16 +91,16 @@ func (Implementation) Dpbtf2(ul blas.Uplo, n, kd int, ab []float64, ldab int) (o
}
return true
}
// Compute the Cholesky factorization A = L * L^T.
for j := 0; j < n; j++ {
// Compute L(J,J) and test for non positive-definiteness.
// Compute L(j,j) and test for non-positive-definiteness.
ajj := ab[j*ldab+kd]
if ajj <= 0 {
return false
}
ajj = math.Sqrt(ajj)
ab[j*ldab+kd] = ajj
// Compute elements J+1:J+KN of column J and update the trailing submatrix
// Compute elements j+1:j+kn of column j and update the trailing submatrix
// within the band.
kn := min(kd, n-j-1)
if kn > 0 {