func main() {

	// filename
	filename, fnkey := io.ArgToFilename(0, "sg111", ".sim", true)

	// fem
	if !fem.Start(filename, false, false, false) {
		io.PfRed("Start failed\n")
		return
	}
	dom, sum, ok := fem.AllocSetAndInit(0, true, true)
	if !ok {
		io.PfRed("AllocSetAndInit failed\n")
		return
	}

	// selected node and dof index
	nidx := 1
	didx := 1

	// gofem
	ntout := len(sum.OutTimes)
	uy := make([]float64, ntout)
	for tidx, _ := range sum.OutTimes {

		// read results from file
		if !dom.In(sum, tidx, true) {
			io.PfRed("plot_spo751: cannot read solution\n")
			return
		}

		// collect results for load versus time plot
		nod := dom.Nodes[nidx]
		eq := nod.Dofs[didx].Eq
		uy[tidx] = dom.Sol.Y[eq]

		// check
		if math.Abs(dom.Sol.T-sum.OutTimes[tidx]) > 1e-14 {
			io.PfRed("output times do not match time in solution array\n")
			return
		}
	}

	// plot fem results
	plt.SetForPng(0.8, 400, 200)
	plt.Plot(sum.OutTimes, uy, "'ro-', clip_on=0, label='gofem'")

	// analytical solution
	tAna := utl.LinSpace(0, 5, 101)
	uyAna := make([]float64, len(tAna))
	for i, t := range tAna {
		uyAna[i] = solution_uy(t, 1.0)
	}
	plt.Plot(tAna, uyAna, "'g-', clip_on=0, label='analytical'")

	// save
	plt.Gll("$t$", "$u_y$", "")
	plt.SaveD("/tmp", fnkey+".png")
}
func main() {

	// filename
	filename, fnkey := io.ArgToFilename(0, "rjoint01", ".sim", true)

	// fem
	if !fem.Start(filename, false, false, false) {
		io.PfRed("Start failed\n")
		return
	}
	dom, sum, ok := fem.AllocSetAndInit(0, true, true)
	if !ok {
		io.PfRed("AllocSetAndInit failed\n")
		return
	}

	// rjoint element
	eid := 2
	ele := dom.Elems[eid].(*fem.Rjoint)
	ipd := ele.OutIpsData()

	// load results from file
	n := len(sum.OutTimes)
	mtau0 := make([]float64, n)
	mtau1 := make([]float64, n)
	mtau2 := make([]float64, n)
	ompb0 := make([]float64, n)
	ompb1 := make([]float64, n)
	ompb2 := make([]float64, n)
	for i, _ := range sum.OutTimes {
		if !dom.In(sum, i, true) {
			io.PfRed("cannot read solution\n")
			return
		}
		res0 := ipd[0].Calc(dom.Sol)
		res1 := ipd[1].Calc(dom.Sol)
		res2 := ipd[2].Calc(dom.Sol)
		mtau0[i] = -res0["tau"]
		mtau1[i] = -res1["tau"]
		mtau2[i] = -res2["tau"]
		ompb0[i] = res0["ompb"]
		ompb1[i] = res1["ompb"]
		ompb2[i] = res2["ompb"]
	}

	// plot
	plt.SetForPng(0.8, 400, 200)
	plt.Plot(ompb0, mtau0, "'r-', marker='.', label='p0', clip_on=0")
	plt.Plot(ompb1, mtau1, "'g-', marker='.', label='p1', clip_on=0")
	plt.Plot(ompb2, mtau2, "'b-', marker='.', label='p2', clip_on=0")
	plt.Gll("$\\bar{\\omega}_p$", "$-\\tau$", "")
	plt.SaveD("/tmp", fnkey+".png")
}