// For use with solve.Iterative:
func CritTempStages(env *tempAll.Environment) ([]solve.DiffSystem, []vec.Vector, func([]vec.Vector)) {
vars0 := []string{"D1", "Mu_h"}
vars1 := []string{"Beta"}
diffD1 := tempPair.AbsErrorD1(env, vars0)
diffMu_h := tempPair.AbsErrorBeta(env, vars0)
system0 := solve.Combine([]solve.Diffable{diffD1, diffMu_h})
diffBeta := AbsErrorBeta(env, vars1)
system1 := solve.Combine([]solve.Diffable{diffBeta})
stages := []solve.DiffSystem{system0, system1}
start := []vec.Vector{[]float64{env.D1, env.Mu_h}, []float64{env.Beta}}
accept := func(x []vec.Vector) {
env.D1 = x[0][0]
env.Mu_h = x[0][1]
env.Beta = x[1][0]
}
return stages, start, accept
}