Repository: gonum/gonum (go)

Issue:
graph/path/dynamic: annotate nolint on poisoned key tests
### What are you trying to do?

Read the D* lite algorithm.

### What did you do?

Looking over the code of the D* lite algorithm I noticed this:

https://github.com/gonum/gonum/blob/5d5638e6749a344a69611ea36989c7dcbdd2dc8d/graph/path/dynamic/dstarlite.go#L416

Unless I'm missing something, this doesn't look quite right :-)

### What did you expect to happen?

I was trying to work out what this failure case was expected to be. Perhaps

```
	if k == badKey || other == badKey {
```

### What actually happened?

N/A

### What version of Go and Gonum are you using?
Master branch of Gonum.

### Does this issue reproduce with the current master?
Yes


Pull request description:
dynamic: clarify use of inequality with float-based keys
Please take a look.

Fixes #1116.

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Patch:
diff --git a/AUTHORS b/AUTHORS
index 194f39bf..b407b2ae 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -65,6 +65,7 @@ Martin Diz <github@martindiz.com.ar>
 Matthieu Di Mercurio <matthieu.dimercurio@gmail.com>
 Max Halford <maxhalford25@gmail.com>
 MinJae Kwon <k239507@gmail.com>
+Nathan Edwards <etaoinshrdluwho@gmail.com>
 Nick Potts <nick@the-potts.com>
 Nils Wogatzky <odog@netcologne.de>
 Olivier Wulveryck <olivier.wulveryck@gmail.com>
diff --git a/CONTRIBUTORS b/CONTRIBUTORS
index 1b16a4ff..1b6e3414 100644
--- a/CONTRIBUTORS
+++ b/CONTRIBUTORS
@@ -71,6 +71,7 @@ Martin Diz <github@martindiz.com.ar>
 Matthieu Di Mercurio <matthieu.dimercurio@gmail.com>
 Max Halford <maxhalford25@gmail.com>
 MinJae Kwon <k239507@gmail.com>
+Nathan Edwards <etaoinshrdluwho@gmail.com>
 Nick Potts <nick@the-potts.com>
 Nils Wogatzky <odog@netcologne.de>
 Olivier Wulveryck <olivier.wulveryck@gmail.com>
diff --git a/graph/path/dynamic/dstarlite.go b/graph/path/dynamic/dstarlite.go
index 3dc0acce..f388b698 100644
--- a/graph/path/dynamic/dstarlite.go
+++ b/graph/path/dynamic/dstarlite.go
@@ -406,14 +406,18 @@ queue:
 // key is a D* Lite priority queue key.
 type key [2]float64
 
+// badKey is a poisoned key. Testing for a bad key uses NaN inequality.
 var badKey = key{math.NaN(), math.NaN()}
 
+//nolint:staticcheck
+func (k key) isBadKey() bool { return k != k }
+
 // less returns whether k is less than other. From ISBN:0-262-51129-0 pp476-483:
 //
 //  k ≤ k' iff k₁ < k'₁ OR (k₁ == k'₁ AND k₂ ≤ k'₂)
 //
 func (k key) less(other key) bool {
-	if k != k || other != other {
+	if k.isBadKey() || other.isBadKey() {
 		panic("D* Lite: poisoned key")
 	}
 	return k[0] < other[0] || (k[0] == other[0] && k[1] < other[1])
diff --git a/integrate/simpsons.go b/integrate/simpsons.go
new file mode 100644
index 00000000..773845bd
--- /dev/null
+++ b/integrate/simpsons.go
@@ -0,0 +1,90 @@
+// Copyright ©2019 The Gonum Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package integrate
+
+import "sort"
+
+// Simpson's method approximates the integral of a function f(x)
+// by means of subdividing the interval of integration into segments
+// and applying a method that fits a polynomial to each subinterval.
+// This implementation makes use of the following composite Simpson's method
+// to estimate \int_a^b f(x) dx where a, b are x at x[0] and x[len(x)-1] respectively:
+//  \sum_{i=1}^{N} {a_0}_i * f_{2i} + {a_1}_i * f_{i} + {a_2}_i * f_{i+1}
+// where N is the count of subintervals and {a_0}_i, {a_1}_i, and {a_2}_i are constants at index i given by:
+//  {a_0}_i * f_{N-2} + {a_1}_i * f_{N-1} + {a_2}_i * f_{N}
+// where the coefficients are:
+//  {a_0}_i = 2 * h^{3}_{i} - h^{3}_{i+1} + 3 * h_{i+1} * h^{2}_{i} /
+//            6 * h_{i} * (h_{i} + h_{i+1})
+//  {a_1}_i = h^{3}_{i} + h^{3}_{i+1} +
+//            3 * h_{i} * h_{i+1} * (h_{i} + h_{i+1}) /
+//            6 * h_{i} * h_{i+1}
+//  {a_2}_i = -h^{3}_{i} + 2 * h^{3}_{i+1} + 3 * h_{i} * h^{2}_{i+1} /
+//            6 * h_{i+1} * (h_{i} + h_{i+1})
+// where h_{k} is the difference x[k] - x[(k-1)].
+// The formula above approximates the integral of function of f if N is an even number of subintervals.
+// If the number of subintervals are odd, the subintervals up i=0..n-2 are given by the above
+// and the approximations over the second to last and last subintervals are given by:
+//  {a_0}_i * f_{N-2} + {a_1}_i * f_{N-1} + {a_2}_i * f_{N}
+// where the coefficients are:
+//  {a_0}_i = -1 * h^{3}_{N-1} /
+//             6 * h_{N-2} * (h_{N-2} + h_{N-1})
+//  {a_1}_i = h^{2}_{N-1} + 3 * h^{3}_{N-1} * h_{N-2} /
+//            6 * h_{N-2}
+//  {a_2}_i = 2 * h^{2}_{N-1} + 3 * h^{2}_{N-1} * h_{N-2} /
+//            6 * (h_{N-2} + h_{N-1})
+// More information is available at:
+// https://en.wikipedia.org/wiki/Simpson%27s_rule#Composite_Simpson's_rule_for_irregularly_spaced_data
+//
+// The (x,f) input data points must be sorted along x. One can use stat.SortWeighted to do that.
+// The x and f slices must be of equal length and the length must be greater than two.
+func Simpsons(x, f []float64) float64 {
+	switch {
+	case len(x) != len(f):
+		panic("integrate: slice length mismatch")
+	case len(x) <= 2:
+		panic("integrate: input data too small")
+	case !sort.Float64sAreSorted(x):
+		panic("integrate: must be sorted")
+	}
+
+	var integral float64
+	for i := 1; i < len(x)-1; i += 2 {
+		if x[i] == x[i-1] || x[i] == x[i+1] {
+			panic("integrate: repeated abscissa are not allowed")
+		}
+		h0 := x[i] - x[i-1]
+		h0p2 := h0 * h0
+		h0p3 := h0 * h0 * h0
+		h1 := x[i+1] - x[i]
+		h1p2 := h1 * h1
+		h1p3 := h1 * h1 * h1
+		hph := h0 + h1
+		f0 := f[i-1]
+		f1 := f[i]
+		f2 := f[i+1]
+		a0 := (2*h0p3 - h1p3 + 3*h1*h0p2) / (6 * h0 * hph)
+		a1 := (h0p3 + h1p3 + 3*h0*h1*hph) / (6 * h0 * h1)
+		a2 := (-h0p3 + 2*h1p3 + 3*h0*h1p2) / (6 * h1 * hph)
+		integral += a0 * f0
+		integral += a1 * f1
+		integral += a2 * f2
+	}
+
+	if len(x)%2 == 0 {
+		h0 := x[len(x)-2] - x[len(x)-3]
+		h1 := x[len(x)-1] - x[len(x)-2]
+		h1p2 := h1 * h1
+		h1p3 := h1 * h1 * h1
+		hph := h0 + h1
+		a0 := -1 * h1p3 / (6 * h0 * hph)
+		a1 := (h1p2 + 3*h0*h1) / (6 * h0)
+		a2 := (2*h1p2 + 3*h0*h1) / (6 * hph)
+		integral += a0 * f[len(x)-3]
+		integral += a1 * f[len(x)-2]
+		integral += a2 * f[len(x)-1]
+	}
+
+	return integral
+}
diff --git a/mathext/airy.go b/mathext/airy.go
index c94c5d84..7b8865f1 100644
--- a/mathext/airy.go
+++ b/mathext/airy.go
@@ -17,7 +17,7 @@ func AiryAi(z complex128) complex128 {
 	// documentation for the exact behavior.
 	id := 0
 	kode := 1
-	air, aii, _ := amos.Zairy(real(z), imag(z), id, kode)
+	air, aii, _, _ := amos.Zairy(real(z), imag(z), id, kode)
 	return complex(air, aii)
 }
 
@@ -32,6 +32,6 @@ func AiryAiDeriv(z complex128) complex128 {
 	// documentation for the exact behavior.
 	id := 1
 	kode := 1
-	air, aii, _ := amos.Zairy(real(z), imag(z), id, kode)
+	air, aii, _, _ := amos.Zairy(real(z), imag(z), id, kode)
 	return complex(air, aii)
 }
diff --git a/mathext/internal/amos/amos.go b/mathext/internal/amos/amos.go
index 35648ceb..79f830a2 100644
--- a/mathext/internal/amos/amos.go
+++ b/mathext/internal/amos/amos.go
@@ -42,7 +42,7 @@ func max(a, b int) int {
 	return b
 }
 
-func Zairy(ZR, ZI float64, ID, KODE int) (AIR, AII float64, NZ int) {
+func Zairy(ZR, ZI float64, ID, KODE int) (AIR, AII float64, NZ, IERR int) {
 	// zairy is adapted from the original Netlib code by Donald Amos.
 	// http://www.netlib.no/netlib/amos/zairy.f
 
@@ -179,7 +179,7 @@ func Zairy(ZR, ZI float64, ID, KODE int) (AIR, AII float64, NZ int) {
 		DK, D1, D2, ELIM, FID, FNU, PTR, RL, R1M5, SFAC, STI, STR,
 		S1I, S1R, S2I, S2R, TOL, TRM1I, TRM1R, TRM2I, TRM2R, TTH, ZEROI,
 		ZEROR, ZTAI, ZTAR, Z3I, Z3R, ALAZ, BB float64
-	var IERR, IFLAG, K, K1, K2, MR, NN int
+	var IFLAG, K, K1, K2, MR, NN int
 	var tmp complex128
 
 	// Extra element for padding.
@@ -420,7 +420,7 @@ OneHundred:
 	if ZI < 0.0e0 {
 		MR = -1
 	}
-	ZTAR, ZTAI, FNU, KODE, MR, _, CYR, CYI, NN, RL, TOL, ELIM, ALIM = Zacai(ZTAR, ZTAI, FNU, KODE, MR, 1, CYR, CYI, NN, RL, TOL, ELIM, ALIM)
+	_, _, _, _, _, _, CYR, CYI, NN, _, _, _, _ = Zacai(ZTAR, ZTAI, FNU, KODE, MR, 1, CYR, CYI, NN, RL, TOL, ELIM, ALIM)
 	if NN < 0 {
 		goto TwoEighty
 	}
@@ -443,7 +443,7 @@ OneTen:
 		goto TwoTen
 	}
 OneTwenty:
-	ZTAR, ZTAI, FNU, KODE, _, CYR, CYI, NZ, TOL, ELIM, ALIM = Zbknu(ZTAR, ZTAI, FNU, KODE, 1, CYR, CYI, NZ, TOL, ELIM, ALIM)
+	_, _, _, _, _, CYR, CYI, NZ, _, _, _ = Zbknu(ZTAR, ZTAI, FNU, KODE, 1, CYR, CYI, NZ, TOL, ELIM, ALIM)
 
 OneThirty:
 	S1R = CYR[1] * COEF
@@ -1183,7 +1183,7 @@ TwoSeventy:
 	YI[2] = S2I
 TwoEighty:
 	ASCLE = BRY[1]
-	ZDR, ZDI, FNU, N, YR, YI, NZ, RZR, RZI, ASCLE, TOL, ELIM = Zkscl(ZDR, ZDI, FNU, N, YR, YI, NZ, RZR, RZI, ASCLE, TOL, ELIM)
+	_, _, FNU, N, YR, YI, NZ, RZR, RZI, _, TOL, ELIM = Zkscl(ZDR, ZDI, FNU, N, YR, YI, NZ, RZR, RZI, ASCLE, TOL, ELIM)
 	INU = N - NZ
 	if INU <= 0 {
 		return ZR, ZI, FNU, KODE, N, YR, YI, NZ, TOL, ELIM, ALIM
@@ -1213,7 +1213,6 @@ TwoNinety:
 
 	// SCALE BY math.Exp(Z), IFLAG = 1 CASES.
 
-	KODED = 2
 	IFLAG = 1
 	KFLAG = 2
 	goto OneTwenty
@@ -1457,14 +1456,14 @@ Twenty:
 		goto Thirty
 	}
 	// ASYMPTOTIC EXPANSION FOR LARGE Z FOR THE I FUNCTION.
-	ZNR, ZNI, FNU, KODE, NN, YR, YI, NW, RL, TOL, ELIM, ALIM = Zasyi(ZNR, ZNI, FNU, KODE, NN, YR, YI, NW, RL, TOL, ELIM, ALIM)
+	ZNR, ZNI, FNU, KODE, _, YR, YI, NW, RL, TOL, ELIM, ALIM = Zasyi(ZNR, ZNI, FNU, KODE, NN, YR, YI, NW, RL, TOL, ELIM, ALIM)
 	if NW < 0 {
 		goto Eighty
 	}
 	goto Forty
 Thirty:
 	// MILLER ALGORITHM NORMALIZED BY THE SERIES FOR THE I FUNCTION
-	ZNR, ZNI, FNU, KODE, NN, YR, YI, NW, TOL = Zmlri(ZNR, ZNI, FNU, KODE, NN, YR, YI, NW, TOL)
+	ZNR, ZNI, FNU, KODE, _, YR, YI, NW, TOL = Zmlri(ZNR, ZNI, FNU, KODE, NN, YR, YI, NW, TOL)
 	if NW < 0 {
 		goto Eighty
 	}
@@ -1511,7 +1510,7 @@ Sixty:
 	zn = complex(ZNR, ZNI)
 	c1 = complex(C1R, C1I)
 	c2 = complex(C2R, C2I)
-	c1, c2, NW, IUF = Zs1s2(zn, c1, c2, ASCLE, ALIM, IUF)
+	c1, c2, NW, _ = Zs1s2(zn, c1, c2, ASCLE, ALIM, IUF)
 	C1R = real(c1)
 	C1I = imag(c1)
 	C2R = real(c2)
diff --git a/mathext/internal/cephes/incbi.go b/mathext/internal/cephes/incbi.go
index b878af09..2b612d83 100644
--- a/mathext/internal/cephes/incbi.go
+++ b/mathext/internal/cephes/incbi.go
@@ -16,7 +16,6 @@ func Incbi(aa, bb, yy0 float64) float64 {
 	var a, b, y0, d, y, x, x0, x1, lgm, yp, di, dithresh, yl, yh, xt float64
 	var i, rflg, dir, nflg int
 
-	i = 0
 	if yy0 <= 0 {
 		return (0.0)
 	}
diff --git a/optimize/lbfgs.go b/optimize/lbfgs.go
index 02359dae..588a1523 100644
--- a/optimize/lbfgs.go
+++ b/optimize/lbfgs.go
@@ -70,7 +70,6 @@ func (l *LBFGS) Init(dim, tasks int) int {
 func (l *LBFGS) Run(operation chan<- Task, result <-chan Task, tasks []Task) {
 	l.status, l.err = localOptimizer{}.run(l, l.GradStopThreshold, operation, result, tasks)
 	close(operation)
-	return
 }
 
 func (l *LBFGS) initLocal(loc *Location) (Operation, error) {
diff --git a/optimize/neldermead.go b/optimize/neldermead.go
index 4615bf48..d92db09e 100644
--- a/optimize/neldermead.go
+++ b/optimize/neldermead.go
@@ -105,7 +105,6 @@ func (n *NelderMead) Init(dim, tasks int) int {
 func (n *NelderMead) Run(operation chan<- Task, result <-chan Task, tasks []Task) {
 	n.status, n.err = localOptimizer{}.run(n, math.NaN(), operation, result, tasks)
 	close(operation)
-	return
 }
 
 func (n *NelderMead) initLocal(loc *Location) (Operation, error) {
diff --git a/optimize/newton.go b/optimize/newton.go
index 9519baf3..cc8d53b1 100644
--- a/optimize/newton.go
+++ b/optimize/newton.go
@@ -82,7 +82,6 @@ func (n *Newton) Init(dim, tasks int) int {
 func (n *Newton) Run(operation chan<- Task, result <-chan Task, tasks []Task) {
 	n.status, n.err = localOptimizer{}.run(n, n.GradStopThreshold, operation, result, tasks)
 	close(operation)
-	return
 }
 
 func (n *Newton) initLocal(loc *Location) (Operation, error) {


Test patch:
diff --git a/graph/path/dynamic/dumper_test.go b/graph/path/dynamic/dumper_test.go
index 1ab77210..05646954 100644
--- a/graph/path/dynamic/dumper_test.go
+++ b/graph/path/dynamic/dumper_test.go
@@ -96,7 +96,7 @@ func (d *dumper) dump(withpath bool) {
 					if n.g != n.rhs {
 						fmt.Fprintf(w, "key:%.3f", n.key)
 					}
-					if n.key == n.key {
+					if !n.key.isBadKey() {
 						// Mark keys for nodes in the priority queue.
 						// We use NaN inequality for this check since all
 						// keys not in the queue must have their key set
diff --git a/integrate/simpsons_test.go b/integrate/simpsons_test.go
new file mode 100644
index 00000000..cdaff0c2
--- /dev/null
+++ b/integrate/simpsons_test.go
@@ -0,0 +1,172 @@
+// Copyright ©2019 The Gonum Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package integrate
+
+import (
+	"math"
+	"testing"
+
+	"gonum.org/v1/gonum/floats"
+)
+
+func TestSimpsons(t *testing.T) {
+	x := floats.Span(make([]float64, 1e6), 0, 1)
+	for i, test := range []struct {
+		x    []float64
+		f    func(x float64) float64
+		want float64
+		tol  float64
+	}{
+		{
+			x:    floats.Span(make([]float64, 1e6), 0, 1),
+			f:    func(x float64) float64 { return math.Pi },
+			want: math.Pi,
+			tol:  1e-10,
+		},
+		{
+			x:    floats.Span(make([]float64, 1e6), 0, 1),
+			f:    func(x float64) float64 { return 1.0 },
+			want: 1,
+			tol:  1e-10,
+		},
+		{
+			x:    floats.Span(make([]float64, 3), 0, 2),
+			f:    func(x float64) float64 { return 2*x + 0.5 },
+			want: 5,
+			tol:  1e-12,
+		},
+		{
+			x:    floats.Span(make([]float64, 10), 0, 2),
+			f:    func(x float64) float64 { return 2*x + 0.5 },
+			want: 5,
+			tol:  1e-12,
+		},
+		{
+			x:    floats.Span(make([]float64, 1e6), 0, 2),
+			f:    func(x float64) float64 { return 2*x + 0.5 },
+			want: 5,
+			tol:  1e-12,
+		},
+		{
+			x:    x,
+			f:    func(x float64) float64 { return x },
+			want: 0.5,
+			tol:  1e-12,
+		},
+		{
+			x:    floats.Span(make([]float64, 1e6), -1, 1),
+			f:    func(x float64) float64 { return x },
+			want: 0,
+			tol:  1e-12,
+		},
+		{
+			x:    x,
+			f:    func(x float64) float64 { return x + 10 },
+			want: 10.5,
+			tol:  1e-12,
+		},
+		{
+			x:    x,
+			f:    func(x float64) float64 { return 3*x*x + 10 },
+			want: 11,
+			tol:  1e-12,
+		},
+		{
+			x:    x,
+			f:    func(x float64) float64 { return math.Exp(x) },
+			want: 1.7182818284591876,
+			tol:  1e-12,
+		},
+		{
+			x:    floats.Span(make([]float64, 1e6), 0, math.Pi),
+			f:    func(x float64) float64 { return math.Cos(x) },
+			want: 0,
+			tol:  1e-12,
+		},
+		{
+			x:    floats.Span(make([]float64, 1e6), 0, 2*math.Pi),
+			f:    func(x float64) float64 { return math.Cos(x) },
+			want: 0,
+			tol:  1e-12,
+		},
+		{
+			x:    floats.Span(make([]float64, 1e6*10), 0, math.Pi),
+			f:    func(x float64) float64 { return math.Sin(x) },
+			want: 2,
+			tol:  1e-12,
+		},
+		{
+			x:    floats.Span(make([]float64, 1e6*10), 0, 0.5*math.Pi),
+			f:    func(x float64) float64 { return math.Sin(x) },
+			want: 1,
+			tol:  1e-12,
+		},
+		{
+			x:    floats.Span(make([]float64, 1e6), 0, 2*math.Pi),
+			f:    func(x float64) float64 { return math.Sin(x) },
+			want: 0,
+			tol:  1e-12,
+		},
+		{
+			x: join(floats.Span(make([]float64, 3), 0, math.Pi/3),
+				[]float64{4 * math.Pi / 10},
+				floats.Span(make([]float64, 4), 3*math.Pi/4, math.Pi)),
+			f:    func(x float64) float64 { return math.Sin(x) },
+			want: 2,
+			tol:  1e-2,
+		},
+		{
+			x: join(floats.Span(make([]float64, 30), 0, 5*math.Pi/16),
+				floats.Span(make([]float64, 100), 3*math.Pi/8, math.Pi)),
+			f:    func(x float64) float64 { return math.Sin(x) },
+			want: 2,
+			tol:  1e-4,
+		},
+		{
+			x: join(floats.Span(make([]float64, 1e5), 0, 15),
+				floats.Span(make([]float64, 1e5), 23, 40),
+				floats.Span(make([]float64, 1e5), 50, 80),
+				floats.Span(make([]float64, 1e5), 90, 100)),
+			f:    func(x float64) float64 { return 2 * x },
+			want: 10000,
+			tol:  1e-9,
+		},
+		{
+			x:    []float64{0, 1, 2},
+			f:    func(x float64) float64 { return 2 * x },
+			want: 4,
+			tol:  1e-12,
+		},
+		{
+			x:    []float64{0, 0.2, 2},
+			f:    func(x float64) float64 { return 2 * x },
+			want: 4,
+			tol:  1e-12,
+		},
+		{
+			x:    []float64{0, 1.89, 2},
+			f:    func(x float64) float64 { return 2 * x },
+			want: 4,
+			tol:  1e-12,
+		},
+	} {
+		y := make([]float64, len(test.x))
+		for i, v := range test.x {
+			y[i] = test.f(v)
+		}
+		v := Simpsons(test.x, y)
+		if !floats.EqualWithinAbs(v, test.want, test.tol) {
+			t.Errorf("test #%d: got=%v want=%f\n", i, v, float64(test.want))
+		}
+	}
+}
+
+func join(slices ...[]float64) []float64 {
+	var c []float64
+	for _, s := range slices {
+		c = append(c, s...)
+	}
+	return c
+}
diff --git a/mathext/internal/amos/amos_test.go b/mathext/internal/amos/amos_test.go
index 3f65cdc9..f0516120 100644
--- a/mathext/internal/amos/amos_test.go
+++ b/mathext/internal/amos/amos_test.go
@@ -418,12 +418,13 @@ func zairytest(t *testing.T, x []float64, kode, id int) {
 	KODE := kode
 	ID := id
 
-	AIRfort, AIIfort, NZfort := zairyOrig(ZR, ZI, ID, KODE)
-	AIRamos, AIIamos, NZamos := Zairy(ZR, ZI, ID, KODE)
+	AIRfort, AIIfort, NZfort, IERRfort := zairyOrig(ZR, ZI, ID, KODE)
+	AIRamos, AIIamos, NZamos, IERRamos := Zairy(ZR, ZI, ID, KODE)
 
 	sameF64Approx(t, "zairy air", AIRfort, AIRamos, 1e-12)
 	sameF64Approx(t, "zairy aii", AIIfort, AIIamos, 1e-12)
 	sameInt(t, "zairy nz", NZfort, NZamos)
+	sameInt(t, "zairy ierr", IERRfort, IERRamos)
 }
 
 func zacaitest(t *testing.T, x []float64, is []int, tol float64, n int, yr, yi []float64, kode int) {
diff --git a/mathext/internal/amos/origcode_test.go b/mathext/internal/amos/origcode_test.go
index 56c9e798..e9cf23a8 100644
--- a/mathext/internal/amos/origcode_test.go
+++ b/mathext/internal/amos/origcode_test.go
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//nolint
 package amos
 
 import (
@@ -34,7 +35,7 @@ func max0(a, b int) int {
 	return b
 }
 
-func zairyOrig(ZR, ZI float64, ID, KODE int) (AIR, AII float64, NZ int) {
+func zairyOrig(ZR, ZI float64, ID, KODE int) (AIR, AII float64, NZ, IERR int) {
 	// zairy is adapted from the original Netlib code by Donald Amos.
 	// http://www.netlib.no/netlib/amos/zairy.f
 
@@ -171,7 +172,7 @@ func zairyOrig(ZR, ZI float64, ID, KODE int) (AIR, AII float64, NZ int) {
 		DK, D1, D2, ELIM, FID, FNU, PTR, RL, R1M5, SFAC, STI, STR,
 		S1I, S1R, S2I, S2R, TOL, TRM1I, TRM1R, TRM2I, TRM2R, TTH, ZEROI,
 		ZEROR, ZTAI, ZTAR, Z3I, Z3R, ALAZ, BB float64
-	var IERR, IFLAG, K, K1, K2, MR, NN int
+	var IFLAG, K, K1, K2, MR, NN int
 	var tmp complex128
 
 	// Extra element for padding.