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"# splines_test\n",
"\n",
"\n",
"\n",
"\n",
"**Author:** Federico Carminati \n",
"This notebook tutorial was automatically generated with ROOTBOOK-izer from the macro found in the ROOT repository on Tuesday, May 19, 2026 at 08:37 PM."
]
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" Arguments are defined. "
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"source": [
"Int_t np = 23;\n",
"Double_t a = -0.5;\n",
"Double_t b = 31;"
]
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"source": [
"const Double_t power = 0.75;\n",
"const Double_t eps = (b - a) * 1.e-5;"
]
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{
"cell_type": "markdown",
"id": "d51a2d7a",
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"source": [
"Define the original function"
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"source": [
"TF1 *f = new TF1(\"f\", \"sin(x)*sin(x/10)\", a - 0.05 * (b - a), b + 0.05 * (b - a));"
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"source": [
"Draw function"
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"Info in : created default TCanvas with name c1\n"
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"source": [
"f->SetLineColor(kBlue);\n",
"f->Draw(\"lc\");\n",
"\n",
"TSpline3 *spline3 = nullptr;\n",
"TSpline5 *spline5 = nullptr;\n",
"TLegend *legend = nullptr;\n",
"\n",
"for (Int_t nnp = 2; nnp <= np; ++nnp) {\n",
"\n",
" std::vector xx(nnp), yy(nnp);\n",
"\n",
" // Calculate the knots\n",
" for (Int_t i = 0; i < nnp; ++i) {\n",
" xx[i] = a + (b - a) * TMath::Power(i / Double_t(nnp - 1), power);\n",
" yy[i] = f->Eval(xx[i]);\n",
" }\n",
"\n",
" // Evaluate fifth spline coefficients\n",
" delete spline5;\n",
" spline5 = new TSpline5(TString::Format(\"quintic spline %dknt\", nnp),\n",
" xx.data(), f, nnp, \"b1e1b2e2\", f->Derivative(a), f->Derivative(b),\n",
" (f->Derivative(a + eps) - f->Derivative(a)) / eps,\n",
" (f->Derivative(b) - f->Derivative(b - eps)) / eps);\n",
"\n",
" spline5->SetLineColor(kRed);\n",
" spline5->SetLineWidth(3);\n",
"\n",
" // Draw the quintic spline\n",
" spline5->Draw(\"lcsame\");\n",
"\n",
" // Evaluate third spline coefficients\n",
" delete spline3;\n",
" spline3 = new TSpline3(TString::Format(\"third spline %dknt\", nnp),\n",
" xx.data(), yy.data(), nnp, \"b1e1\", f->Derivative(a), f->Derivative(b));\n",
"\n",
" spline3->SetLineColor(kGreen);\n",
" spline3->SetLineWidth(3);\n",
" spline3->SetMarkerColor(kMagenta);\n",
" spline3->SetMarkerStyle(20);\n",
" spline3->SetMarkerSize(1.5);\n",
"\n",
" // Draw the third spline\n",
" spline3->Draw(\"lcpsame\");\n",
"\n",
" delete legend;\n",
" legend = gPad->BuildLegend(0.6, 0.7, 0.88, 0.88);\n",
"\n",
" gPad->Update();\n",
"\n",
" gSystem->Sleep(500);\n",
"}"
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"Draw all canvases "
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