Files
3f5b3cdd98 feat: add configurable SMTP HELO hostname (#2146)
* feat: add configurable SMTP HELO hostname

Allow the SMTP HELO/EHLO hostname to be configured separately from
the SMTP server hostname.

This is useful when the SMTP server requires clients to identify
themselves with a fully qualified hostname different from the server
address.

* chore: remove vendored dependency changes

* Bump go-pkgz/notify to v1.4.0 and document SMTP_HELO_HOST

The HELOHost field lands in go-pkgz/notify v1.4.0, so the branch needs the
bump to compile; v1.3.0 in master has no such field. The example module is
tidied alongside, as any change to backend/go.mod requires.

Documents the parameter in the parameters table and, separately, in the email
setup page: what it does, that leaving it unset keeps the previous `localhost`
greeting, and the case it exists for, a relay refusing the greeting under
Postfix `reject_non_fqdn_helo_hostname`.

Also records the current limit: verification emails for email authentication
go through go-pkgz/auth's own sender, which has no equivalent setting, so the
greeting there is unchanged.

* Bump go-pkgz/auth to v2.2.0 and apply SMTP_HELO_HOST to verification email

The verification email sender had no way to set the greeting, so a relay that
refuses the HELO would accept notifications and still reject sign-in emails.
EmailParams gains HELOHost in go-pkgz/auth v2.2.0, so the same SMTP_HELO_HOST
now drives both paths.

The example module is tidied alongside, as any change to backend/go.mod
requires.

---------

Co-authored-by: oli <someone@somewhere.tld>
Co-authored-by: Dmitry Verkhoturov <paskal.07@gmail.com>
2026-08-19 02:52:39 -05:00

142 lines
3.3 KiB
Go

package stats
import "math"
// Series is a container for a series of data
type Series []Coordinate
// Coordinate holds the data in a series
type Coordinate struct {
X, Y float64
}
// LinearRegression finds the least squares linear regression on data series.
// A series without at least two distinct X values returns ErrBounds.
func LinearRegression(s Series) (regressions Series, err error) {
if len(s) == 0 {
return nil, EmptyInputErr
}
var sumX, sumY float64
for _, coordinate := range s {
sumX += coordinate.X
sumY += coordinate.Y
}
meanX := sumX / float64(len(s))
meanY := sumY / float64(len(s))
var covariance, variance float64
for _, coordinate := range s {
dx := coordinate.X - meanX
covariance += dx * (coordinate.Y - meanY)
variance += dx * dx
}
if variance == 0 {
return nil, ErrBounds
}
gradient := covariance / variance
// Create the new regression series
for j := 0; j < len(s); j++ {
regressions = append(regressions, Coordinate{
X: s[j].X,
Y: meanY + gradient*(s[j].X-meanX),
})
}
return regressions, nil
}
// ExponentialRegression returns an exponential regression on data series.
// A non-positive Y value returns ErrYCoord, and a series without at least two
// distinct X values returns ErrBounds.
func ExponentialRegression(s Series) (regressions Series, err error) {
if len(s) == 0 {
return nil, EmptyInputErr
}
var sumY, sumDeltaXY, sumYLogY float64
referenceX := s[0].X
for i := 0; i < len(s); i++ {
if s[i].Y <= 0 {
return nil, ErrYCoord
}
sumY += s[i].Y
sumDeltaXY += (s[i].X - referenceX) * s[i].Y
sumYLogY += s[i].Y * math.Log(s[i].Y)
}
meanDeltaX := sumDeltaXY / sumY
meanLogY := sumYLogY / sumY
var covariance, variance float64
for _, coordinate := range s {
dx := coordinate.X - referenceX - meanDeltaX
covariance += coordinate.Y * dx * (math.Log(coordinate.Y) - meanLogY)
variance += coordinate.Y * dx * dx
}
if variance == 0 {
return nil, ErrBounds
}
b := covariance / variance
for j := 0; j < len(s); j++ {
regressions = append(regressions, Coordinate{
X: s[j].X,
Y: math.Exp(meanLogY + b*(s[j].X-referenceX-meanDeltaX)),
})
}
return regressions, nil
}
// LogarithmicRegression returns a logarithmic regression on data series.
// A non-positive X value or a series without at least two distinct X values
// returns ErrBounds.
func LogarithmicRegression(s Series) (regressions Series, err error) {
if len(s) == 0 {
return nil, EmptyInputErr
}
if s[0].X <= 0 {
return nil, ErrBounds
}
logX := make([]float64, len(s))
referenceLogX := math.Log(s[0].X)
var sumDeltaLogX, sumY float64
for i := 0; i < len(s); i++ {
if s[i].X <= 0 {
return nil, ErrBounds
}
logX[i] = math.Log(s[i].X)
sumDeltaLogX += logX[i] - referenceLogX
sumY += s[i].Y
}
meanDeltaLogX := sumDeltaLogX / float64(len(s))
meanY := sumY / float64(len(s))
var covariance, variance float64
for i, coordinate := range s {
dx := logX[i] - referenceLogX - meanDeltaLogX
covariance += dx * (coordinate.Y - meanY)
variance += dx * dx
}
if variance == 0 {
return nil, ErrBounds
}
a := covariance / variance
for j := 0; j < len(s); j++ {
regressions = append(regressions, Coordinate{
X: s[j].X,
Y: meanY + a*(logX[j]-referenceLogX-meanDeltaLogX),
})
}
return regressions, nil
}