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mat: add SymBandDense.Norm

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This commit is contained in:
Vladimir Chalupecky
2021-05-05 13:54:51 +02:00
committed by Vladimír Chalupecký
parent 06f3d524c3
commit dd45c215c4
1 changed files with 21 additions and 0 deletions
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21
mat/symband.go
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@@ -7,6 +7,8 @@ package mat
import ( import (
"gonum.org/v1/gonum/blas" "gonum.org/v1/gonum/blas"
"gonum.org/v1/gonum/blas/blas64" "gonum.org/v1/gonum/blas/blas64"
"gonum.org/v1/gonum/lapack"
"gonum.org/v1/gonum/lapack/lapack64"
) )
var ( var (
@@ -242,6 +244,25 @@ func (s *SymBandDense) DoColNonZero(j int, fn func(i, j int, v float64)) {
} }
} }
// Norm returns the specified norm of the receiver. Valid norms are:
// 1 - The maximum absolute column sum
// 2 - The Frobenius norm, the square root of the sum of the squares of the elements
// Inf - The maximum absolute row sum
//
// Norm will panic with ErrNormOrder if an illegal norm is specified.
func (s *SymBandDense) Norm(norm float64) float64 {
if s.IsEmpty() {
panic(ErrZeroLength)
}
lnorm := normLapack(norm, false)
if lnorm == lapack.MaxColumnSum || lnorm == lapack.MaxRowSum {
work := getFloats(s.mat.N, false)
defer putFloats(work)
return lapack64.Lansb(lnorm, s.mat, work)
}
return lapack64.Lansb(lnorm, s.mat, nil)
}
// Trace returns the trace. // Trace returns the trace.
func (s *SymBandDense) Trace() float64 { func (s *SymBandDense) Trace() float64 {
rb := s.RawSymBand() rb := s.RawSymBand()