Stabilizacijska funkcija

viewof fm_controls = Inputs.form({
  c:  Inputs.range([0.50, 0.85], {value: 0.70, step: 0.01, width: 240, label: "Sklonost potrošnji (c)"}),
  dG: Inputs.range([0,    60],   {value: 30,   step: 1,    width: 240, label: "Porast potrošnje (ΔG)"}),
  dT: Inputs.range([0,    60],   {value: 30,   step: 1,    width: 240, label: "Porast poreza (ΔT)"})
})

{
  const A0 = 100, c = fm_controls.c, dG = fm_controls.dG, dT = fm_controls.dT;
  const Ymax = 1400;
  const Y0  = A0 / (1 - c);
  const Y1G = (A0 + dG) / (1 - c);
  const Y1T = (A0 - c * dT) / (1 - c);
  const multG = 1 / (1 - c);
  const multT = -c / (1 - c);
  const PG = "Povećanje državne potrošnje", PT = "Povećanje poreza";
  const grid = d3.range(0, Ymax + 10, 10);

  const line45 = grid.flatMap(y => [{Y: y, AE: y, policy: PG}, {Y: y, AE: y, policy: PT}]);
  const ae0 = grid.flatMap(y => {
    const ae = A0 + c * y;
    return ae > Ymax ? [] : [{Y: y, AE: ae, policy: PG}, {Y: y, AE: ae, policy: PT}];
  });
  const ae1G = grid.map(y => ({Y: y, AE: A0 + dG + c * y, policy: PG})).filter(p => p.AE <= Ymax);
  const ae1T = grid.map(y => ({Y: y, AE: A0 - c * dT + c * y, policy: PT})).filter(p => p.AE <= Ymax && p.AE >= 0);
  const dots = [
    {Y: Y0, AE: Y0, policy: PG}, {Y: Y1G, AE: Y1G, policy: PG},
    {Y: Y0, AE: Y0, policy: PT}, {Y: Y1T, AE: Y1T, policy: PT}
  ];
  const guides = [
    {Yx: Y0, yTop: Y0, policy: PG}, {Yx: Y1G, yTop: Y1G, policy: PG},
    {Yx: Y0, yTop: Y0, policy: PT}, {Yx: Y1T, yTop: Y1T, policy: PT}
  ];
  const topLabels = [
    {Y: 30, AE: Ymax * 0.95, label: `ΔY/ΔG = ${multG.toFixed(2).replace(".", ",")}`, policy: PG},
    {Y: 30, AE: Ymax * 0.95, label: `ΔY/ΔT = ${multT.toFixed(2).replace(".", ",")}`, policy: PT}
  ];
  const fortyfive = [
    {Y: Ymax * 0.9, AE: Ymax * 0.9, label: "45°", policy: PG},
    {Y: Ymax * 0.9, AE: Ymax * 0.9, label: "45°", policy: PT}
  ];

  return Plot.plot({
    width: 880, height: 420, marginLeft: 56, marginRight: 22, marginBottom: 44, marginTop: 46,
    style: {fontSize: "12px", fontFamily: "Public Sans, system-ui, sans-serif", color: "#3A332D", background: "transparent"},
    fx: {label: null, domain: [PG, PT]},
    x: {label: "Dohodak / proizvodnja (Y) →", domain: [0, Ymax], grid: false},
    y: {label: "↑ Planirani izdaci (AE)", domain: [0, Ymax], grid: true},
    marks: [
      Plot.ruleY([0], {stroke: "#C9C3B8"}),
      Plot.line(line45, {fx: "policy", x: "Y", y: "AE", stroke: "#3A332D", strokeWidth: 1.5}),
      Plot.line(ae0, {fx: "policy", x: "Y", y: "AE", stroke: "#2D5A8E", strokeWidth: 2.5}),
      Plot.line(ae1G, {fx: "policy", x: "Y", y: "AE", stroke: "#2D5A8E", strokeWidth: 2.5, strokeDasharray: "6,4"}),
      Plot.line(ae1T, {fx: "policy", x: "Y", y: "AE", stroke: "#2D5A8E", strokeWidth: 2.5, strokeDasharray: "6,4"}),
      Plot.ruleX(guides, {fx: "policy", x: "Yx", y1: 0, y2: "yTop", stroke: "#6B6357", strokeDasharray: "4,3"}),
      Plot.dot(dots, {fx: "policy", x: "Y", y: "AE", r: 5, fill: "#2D5A8E", stroke: "white", strokeWidth: 2}),
      Plot.text(fortyfive, {fx: "policy", x: "Y", y: "AE", text: "label", fill: "#3A332D", fontSize: 11, dx: 6, dy: -6}),
      Plot.text(topLabels, {fx: "policy", x: "Y", y: "AE", text: "label", textAnchor: "start", fontSize: 13, fill: "#1C1916", fontWeight: 700})
    ]
  });
}

viewof cikl_controls = Inputs.form({
  A:  Inputs.range([0, 3], {value: 1.5, step: 0.1, width: 260, label: "Snaga predizborne manipulacije (A)"}),
  un: Inputs.range([3, 8], {value: 5,   step: 0.5, width: 260, label: "Prirodna stopa nezaposlenosti (%)"})
})

{
  const A = cikl_controls.A, un = cikl_controls.un;
  const frac = (t) => t - Math.floor(t);
  const u = (t) => un + A * Math.cos(Math.PI * frac(t));
  const ts = d3.range(0, 2.001, 0.01);
  const path = ts.map(t => ({t, u: Math.abs(frac(t)) < 1e-9 && t > 0 ? NaN : u(t)}));

  return Plot.plot({
    width: 820, height: 400, marginLeft: 54, marginTop: 36, marginBottom: 46, marginRight: 20,
    style: {fontSize: "12px", fontFamily: "Public Sans, system-ui, sans-serif", color: "#3A332D", background: "transparent"},
    x: {label: "Vrijeme (u mandatima) →", domain: [0, 2]},
    y: {label: "↑ Nezaposlenost (%)", domain: [Math.max(0, un - A - 1), un + A + 1], grid: true},
    marks: [
      Plot.ruleY([un], {stroke: "#6B6357", strokeDasharray: "4,3"}),
      Plot.ruleX([1, 2], {stroke: "#6B1F26", strokeWidth: 1}),
      Plot.line(path, {x: "t", y: "u", stroke: "#2D5A8E", strokeWidth: 2.5}),
      Plot.text([{t: 1, y: un + A + 0.7}], {x: "t", y: "y", text: ["izbori"], fill: "#6B1F26", fontSize: 11, fontWeight: 700}),
      Plot.text([{t: 2, y: un + A + 0.7}], {x: "t", y: "y", text: ["izbori"], fill: "#6B1F26", fontSize: 11, fontWeight: 700}),
      Plot.text([{t: 0.02, y: un}], {x: "t", y: "y", text: ["prirodna stopa"], textAnchor: "start", dy: -6, fill: "#6B6357", fontSize: 10})
    ]
  });
}