fit: fix polynomial regression for d >= 4

aclements · aclements · commit 033754ab1fee · 2017-02-10T14:34:28.000-05:00
This stumbled over the classic capturing-the-loop-variable bug so all
terms from degree 3 and on used the highest degree.
diff --git a/fit/lsquares.go b/fit/lsquares.go
@@ -152,6 +152,7 @@ func PolynomialRegression(xs, ys, weights []float64, degree int) PolynomialRegre
 		}
 	}
 	for d := 3; d < len(terms); d++ {
+		d := d
 		terms[d] = func(xs, termOut []float64) {
 			for i, x := range xs {
 				termOut[i] = math.Pow(x, float64(d+1))

Original file line number	Diff line number	Diff line change
`@@ -152,6 +152,7 @@ func PolynomialRegression(xs, ys, weights []float64, degree int) PolynomialRegre`
`152`	`152`	`}`
`153`	`153`	`}`
`154`	`154`	`for d := 3; d < len(terms); d++ {`
	`155`	`+ d := d`
`155`	`156`	`terms[d] = func(xs, termOut []float64) {`
`156`	`157`	`for i, x := range xs {`
`157`	`158`	`termOut[i] = math.Pow(x, float64(d+1))`