[ode] Remove unused test (amplifier)

ode/problems.go

@@ -65,7 +65,8 @@ func (o *Problem) Solve(method string, fixedStp, numJac bool) (y la.Vector, stat
 }
 
 // ConvergenceTest runs convergence test
-//   yExact -- is the exact (reference) y @ xf
+//
+//	yExact -- is the exact (reference) y @ xf
 func (o *Problem) ConvergenceTest(tst *testing.T, dxmin, dxmax float64, ndx int, yExact la.Vector,
 	methods []string, orders, tols []float64) {
 
@@ -145,9 +146,10 @@ func ProbHwEq11() (o *Problem) {
 }
 
 // ProbVanDerPol returns the Van der Pol' Equation as given in Hairer-Wanner VII-p5 Eq.(1.5)
-//  eps  -- ε coefficient; use 0 for default value [=1e-6]
-//  stationary -- use eps=1 and compute period and amplitude such that
-//                y = [A, 0] is a stationary point
+//
+//	eps  -- ε coefficient; use 0 for default value [=1e-6]
+//	stationary -- use eps=1 and compute period and amplitude such that
+//	              y = [A, 0] is a stationary point
 func ProbVanDerPol(eps float64, stationary bool) (o *Problem) {
 
 	o = new(Problem)
@@ -218,100 +220,6 @@ func ProbRobertson() (o *Problem) {
 	return
 }
 
-// ProbHwAmplifier returns the Hairer-Wanner VII-p376 Transistor Amplifier
-// NOTE: from E. Hairer's website, not the equation in the book
-func ProbHwAmplifier() (o *Problem) {
-
-	// problem
-	o = new(Problem)
-	o.Xf = 0.05
-	//o.Xf = 0.0123 // OK
-	//o.Xf = 0.01235 // !OK
-
-	// constants
-	ue, ub, uf, α, β := 0.1, 6.0, 0.026, 0.99, 1.0e-6
-	r0, r1, r2, r3, r4, r5 := 1000.0, 9000.0, 9000.0, 9000.0, 9000.0, 9000.0
-	r6, r7, r8, r9 := 9000.0, 9000.0, 9000.0, 9000.0
-	w := 2.0 * 3.141592654 * 100.0
-
-	// initial values
-	o.Y = la.NewVectorSlice([]float64{
-		0.0,
-		ub,
-		ub / (r6/r5 + 1.0),
-		ub / (r6/r5 + 1.0),
-		ub,
-		ub / (r2/r1 + 1.0),
-		ub / (r2/r1 + 1.0),
-		0.0,
-	})
-	o.Ndim = len(o.Y)
-
-	// right-hand side of the amplifier problem
-	o.Fcn = func(f la.Vector, dx, x float64, y la.Vector) {
-		uet := ue * math.Sin(w*x)
-		fac1 := β * (math.Exp((y[3]-y[2])/uf) - 1.0)
-		fac2 := β * (math.Exp((y[6]-y[5])/uf) - 1.0)
-		f[0] = y[0] / r9
-		f[1] = (y[1]-ub)/r8 + α*fac1
-		f[2] = y[2]/r7 - fac1
-		f[3] = y[3]/r5 + (y[3]-ub)/r6 + (1.0-α)*fac1
-		f[4] = (y[4]-ub)/r4 + α*fac2
-		f[5] = y[5]/r3 - fac2
-		f[6] = y[6]/r1 + (y[6]-ub)/r2 + (1.0-α)*fac2
-		f[7] = (y[7] - uet) / r0
-	}
-
-	// Jacobian of the amplifier problem
-	o.Jac = func(dfdy *la.Triplet, dx, x float64, y la.Vector) {
-		fac14 := β * math.Exp((y[3]-y[2])/uf) / uf
-		fac27 := β * math.Exp((y[6]-y[5])/uf) / uf
-		if dfdy.Max() == 0 {
-			dfdy.Init(8, 8, 16)
-		}
-		nu := 2
-		dfdy.Start()
-		dfdy.Put(2+0-nu, 0, 1.0/r9)
-		dfdy.Put(2+1-nu, 1, 1.0/r8)
-		dfdy.Put(1+2-nu, 2, -α*fac14)
-		dfdy.Put(0+3-nu, 3, α*fac14)
-		dfdy.Put(2+2-nu, 2, 1.0/r7+fac14)
-		dfdy.Put(1+3-nu, 3, -fac14)
-		dfdy.Put(2+3-nu, 3, 1.0/r5+1.0/r6+(1.0-α)*fac14)
-		dfdy.Put(3+2-nu, 2, -(1.0-α)*fac14)
-		dfdy.Put(2+4-nu, 4, 1.0/r4)
-		dfdy.Put(1+5-nu, 5, -α*fac27)
-		dfdy.Put(0+6-nu, 6, α*fac27)
-		dfdy.Put(2+5-nu, 5, 1.0/r3+fac27)
-		dfdy.Put(1+6-nu, 6, -fac27)
-		dfdy.Put(2+6-nu, 6, 1.0/r1+1.0/r2+(1.0-α)*fac27)
-		dfdy.Put(3+5-nu, 5, -(1.0-α)*fac27)
-		dfdy.Put(2+7-nu, 7, 1.0/r0)
-	}
-
-	// "mass" matrix
-	c1, c2, c3, c4, c5 := 1.0e-6, 2.0e-6, 3.0e-6, 4.0e-6, 5.0e-6
-	o.M = new(la.Triplet)
-	o.M.Init(8, 8, 14)
-	o.M.Start()
-	nu := 1
-	o.M.Put(1+0-nu, 0, -c5)
-	o.M.Put(0+1-nu, 1, c5)
-	o.M.Put(2+0-nu, 0, c5)
-	o.M.Put(1+1-nu, 1, -c5)
-	o.M.Put(1+2-nu, 2, -c4)
-	o.M.Put(1+3-nu, 3, -c3)
-	o.M.Put(0+4-nu, 4, c3)
-	o.M.Put(2+3-nu, 3, c3)
-	o.M.Put(1+4-nu, 4, -c3)
-	o.M.Put(1+5-nu, 5, -c2)
-	o.M.Put(1+6-nu, 6, -c1)
-	o.M.Put(0+7-nu, 7, c1)
-	o.M.Put(2+6-nu, 6, c1)
-	o.M.Put(1+7-nu, 7, -c1)
-	return
-}
-
 // ProbArenstorf returns the Arenstorf orbit problem
 func ProbArenstorf() (o *Problem) {
 	o = new(Problem)

ode/t_ode_test.go

@@ -6,7 +6,6 @@ package ode
 
 import (
 	"testing"
-	"time"
 
 	"github.com/cpmech/gosl/chk"
 	"github.com/cpmech/gosl/io"
@@ -149,42 +148,3 @@ func TestOde03(tst *testing.T) {
 	chk.Int(tst, "number of lin solutions ", sol.Stat.Nlinsol, 24)
 	chk.Int(tst, "max number of iterations", sol.Stat.Nitmax, 2)
 }
-
-func TestOde04(tst *testing.T) {
-
-	//verbose()
-	chk.PrintTitle("ode04: Hairer-Wanner VII-p376 Transistor Amplifier")
-
-	// problem
-	p := ProbHwAmplifier()
-
-	// configurations
-	conf := NewConfig("radau5", "")
-	conf.SetStepOut(true, nil)
-	conf.IniH = 1.0e-6 // initial step size
-
-	// set tolerances
-	atol, rtol := 1e-11, 1e-5
-	conf.SetTols(atol, rtol)
-
-	// ODE solver
-	sol := NewSolver(p.Ndim, conf, p.Fcn, p.Jac, p.M)
-	defer sol.Free()
-
-	// run
-	t0 := time.Now()
-	sol.Solve(p.Y, 0.0, p.Xf)
-	io.Pfmag("elapsed time = %v\n", time.Now().Sub(t0))
-
-	// check
-	if false { // these values vary slightly in different machines
-		chk.Int(tst, "number of F evaluations ", sol.Stat.Nfeval, 2599)
-		chk.Int(tst, "number of J evaluations ", sol.Stat.Njeval, 216)
-		chk.Int(tst, "total number of steps   ", sol.Stat.Nsteps, 275)
-		chk.Int(tst, "number of accepted steps", sol.Stat.Naccepted, 219)
-		chk.Int(tst, "number of rejected steps", sol.Stat.Nrejected, 20)
-		chk.Int(tst, "number of decompositions", sol.Stat.Ndecomp, 274)
-		chk.Int(tst, "number of lin solutions ", sol.Stat.Nlinsol, 792)
-		chk.Int(tst, "max number of iterations", sol.Stat.Nitmax, 6)
-	}
-}