lapack/gonum: clean up implementation comments in Dpbtf2
@@ -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 {
