GeneratingFunction[expr,n,x]
给出 x 的序列的生成函数,其中第 n
级数系数由表达式 expr 给出.
GeneratingFunction[expr,{n1,…,nm},{x1,…,xm}]
给出 x1,…,xm 的多维生成函数,其中 n1,… ,nm 系数由 expr 给出.
GeneratingFunction
GeneratingFunction[expr,n,x]
给出 x 的序列的生成函数,其中第 n
级数系数由表达式 expr 给出.
GeneratingFunction[expr,{n1,…,nm},{x1,…,xm}]
给出 x1,…,xm 的多维生成函数,其中 n1,… ,nm 系数由 expr 给出.
更多信息和选项
- 一个序列的生成函数,其中第 n
项是 an,由
给出. - 多维生成函数由
给出. - 可以给出下列选项:
-
Assumptions $Assumptions 关于参数的假设 GenerateConditions False 是否产生关于参数条件的结果 Method Automatic 使用的方法 VerifyConvergence True 是否验证收敛 - 在 TraditionalForm 中,用
输出 GeneratingFunction.
范例
打开所有单元 关闭所有单元基本范例 (3)
GeneratingFunction[1, n, x]Series[%, {x, 0, 10}]GeneratingFunction[(1/n!^2), n, x]GeneratingFunction[(1/(n + 1)! m!), {n, m}, {x, y}]GeneratingFunction[f[n + 1], n, x]范围 (23)
基本用途 (7)
GeneratingFunction[a ^ n, n, z]GeneratingFunction[1 / (m!n!), {m, n}, {x, y}]F = GeneratingFunction[n (n + 1)(-1 / 2) ^ n, n, z]使用 Plot3D、ContourPlot 或 DensityPlot 绘制幅度:
Block[{z = u + I v}, Table[plot[Abs[F], {u, -2, 2}, {v, -2, 2}], {plot, {Plot3D, ContourPlot, DensityPlot}}]]Block[{z = u + I v}, Table[plot[Arg[F], {u, -2, 2}, {v, -2, 2}], {plot, {Plot3D, ContourPlot, DensityPlot}}]]GeneratingFunction[a ^ n, n, z, GenerateConditions -> True]With[{z = u + I v}, RegionPlot[Abs[z] < 1 / Abs[1 / 2], {u, -4, 4}, {v, -4, 4}]]F = GeneratingFunction[Sin[n 2Pi / 3](2 / 3) ^ n, n, Exp[I ω]]LogPlot[Abs[F] ^ 2, {ω, 0, 2π}, Ticks -> {{0, π, 2π}, Automatic}]Plot[Arg[F], {ω, 0, 2π}, Ticks -> {{0, π, 2π}, Automatic}]LogPlot[Abs[F] ^ 2, {ω, 0, 2π}, Ticks -> {{0, π, 2π}, Automatic}, ColorFunction -> Function[ω, Evaluate@Hue[Arg[F] / (2Pi) + 1 / 2]], ColorFunctionScaling -> False, Filling -> Axis]使用 ParametricPlot3D 在复平面绘制频谱:
ParametricPlot3D[{Cos[ω], Sin[ω], Log[10, Abs[F] ^ 2]}, {ω, 0, 2π}, BoxRatios -> {1, 1, 1}]GeneratingFunction 会使用多个属性包括线性:
GeneratingFunction[a f[n] + b g[n], n, z]{GeneratingFunction[f[n + 1], n, z], GeneratingFunction[f[n - 1], n, z]}{GeneratingFunction[a ^ n f[n], n, z], GeneratingFunction[b ^ (-n)f[n], n, z]}GeneratingFunction[Exp[I ω n]f[n], n, z]{GeneratingFunction[ n f[n], n, z], GeneratingFunction[n(n + 1) f[n], n, z]}GeneratingFunction[Conjugate[f[n]], n, z]GeneratingFunction 自动线性作用于列表:
GeneratingFunction[{a ^ n, b ^ n}, n, z]GeneratingFunction[{{a ^ n, b ^ n}, {n, n ^ 2}}, n, z]GeneratingFunction[a ^ n == f[n], n, z]GeneratingFunction[f[n] -> a ^ n, n, z]TraditionalForm 排版:
GeneratingFunction[f[n], n, z]//TraditionalForm特殊序列 (12)
{GeneratingFunction[DiscreteDelta[n], n, z], GeneratingFunction[DiscreteDelta[n - 5], n, z]}Table[DiscretePlot[f, {n, -10, 10}, PlotStyle -> PointSize[Medium]], {f, {DiscreteDelta[n], DiscreteDelta[n - 5]}}]{GeneratingFunction[UnitStep[n], n, z], GeneratingFunction[UnitStep[n - 3], n, z]}Table[DiscretePlot[f, {n, -10, 10}], {f, {UnitStep[n], UnitStep[n - 3]}}]{GeneratingFunction[n UnitStep[n], n, z], GeneratingFunction[(n - 3)UnitStep[n - 3], n, z]}Table[DiscretePlot[f, {n, -10, 10}], {f, {n UnitStep[n], (n - 3)UnitStep[n - 3]}}]{GeneratingFunction[n, n, z], GeneratingFunction[n ^ 2, n, z]}GeneratingFunction[Pochhammer[n, Range[0, 3]], n, z]GeneratingFunction[FactorialPower[n, Range[0, 3]], n, z]GeneratingFunction[a ^ n, n, z]{GeneratingFunction[n a ^ n, n, z], GeneratingFunction[n ^ 2 a ^ n, n, z]}Table[DiscretePlot[f, {n, 0, 40}], {f, {n (10 / 12) ^ n, n ^ 2 (10 / 12) ^ n}}]GeneratingFunction[Pochhammer[n, Range[0, 3]] a ^ n, n, z]GeneratingFunction[FactorialPower[n, Range[0, 3]] a ^ n, n, z]{GeneratingFunction[Sin[ω n + ϕ], n, z], GeneratingFunction[Cos[ω n + ϕ], n, z]}Table[DiscretePlot[f, {n, -20, 20}], {f, {Sin[2π / 10 n], Cos[2π / 10 n]}}]{GeneratingFunction[(5 / 6) ^ n Sin[ω n], n, z], GeneratingFunction[n (5 / 6) ^ n Sin[ω n], n, z]}Table[DiscretePlot[f, {n, 0, 20}], {f, {(5 / 6) ^ n Sin[2π / 10 n], n (5 / 6) ^ n Sin[2π / 10 n]}}]GeneratingFunction[n ^ 2 a ^ n + b ^ n Sin[ω n] UnitStep[n + 20], n, z]DiscretePlot[n ^ 2 (5 / 6) ^ n + (11 / 12) ^ n 20Sin[2Pi / 10 n]UnitStep[n - 20], {n, 0, 50}]GeneratingFunction[n (UnitStep[n] - UnitStep[n - 6]) + a ^ n UnitStep[n - 6], n, z]GeneratingFunction[Piecewise[{{n, n ≤ 5}, {a ^ n, True}}], n, z]Simplify[%% - %]GeneratingFunction[1 / (n + 1), n, z]GeneratingFunction[(n^2 + n + 1) / (n + 1) ^ 2, n, z]GeneratingFunction[FactorialPower[n, -2], n, z]GeneratingFunction[a ^ n / (n + 1) ^ 2, n, z]GeneratingFunction[a ^ n FactorialPower[n, -2], n, z]GeneratingFunction[1 / n!, n, z]DiscreteRatio 对于所有超几何项序列都是有理的:
DiscreteRatio[1 / n!, n]hl = {a ^ n, n!, Gamma[n], Pochhammer[a, n], FactorialPower[a, n], Binomial[n, a], Binomial[b, n], CatalanNumber[n]};DiscreteRatio[hl, n]DiscreteRatio[Times@@RandomChoice[hl, 3], n]GeneratingFunction[(2^-2 + n/Gamma[(1/2) + n]), n, z]GeneratingFunction[n / Binomial[2n, n], n, z]GeneratingFunction[CatalanNumber[n] / Binomial[2n, n], n, z]GeneratingFunction[(FactorialPower[a1, n]/FactorialPower[b1, n]FactorialPower[b2, n]), n, z]GeneratingFunction[LegendreP[n, a], n, z]DifferenceRootReduce[LegendreP[n, a], n]GeneratingFunction[ChebyshevT[n, x], n, z]GeneratingFunction[ChebyshevU[2n, x] ^ 2, n, z]GeneratingFunction[BernoulliB[n] / n!, n, z]GeneratingFunction[EulerE[n] / n!, n, z]GeneratingFunction[DifferenceRoot[Function[{y, m}, {y[m + 2] == y[m + 1] + y[m], y[0] == 0, y[1] == 1}]][n], n, z]GeneratingFunction[Mod[n, 3], n, z]GeneratingFunction[Exp[n 2π I / 9], n, z]GeneratingFunction[a^n + m, {n, m}, {u, v}]GeneratingFunction[n ^ 2 m ^ 3, {n, m}, {u, v}]GeneratingFunction[Sin[n + m]a ^ n, {n, m}, {u, v}]GeneratingFunction[m / (n + 1), {n, m}, {u, v}]GeneratingFunction[Mod[n + m, 3], {n, m}, {u, v}]特殊运算 (4)
GeneratingFunction[a * f[n] + b * f[n], n, z]GeneratingFunction[DifferenceDelta[f[n], n], n, z]GeneratingFunction[DiscreteShift[f[n], n], n, z]GeneratingFunction[Sum[f[m], {m, 0, n}], n, z]GeneratingFunction[Sum[f[m], {m, a, n}], n, z, Assumptions -> a > 0 && a∈Integers]GeneratingFunction[Integrate[f[x, n], {x, a, b}], n, z]推广和延伸 (1)
选项 (6)
Assumptions (1)
GeneratingFunction[f[n + a], n, x]通过提供 Assumptions,给出一个封闭形式:
GeneratingFunction[f[n + a], n, x, Assumptions -> a∈Integers && a > 0]GenerateConditions (1)
GeneratingFunction[a ^ n, n, x]用 GenerateConditions 生成有效条件:
GeneratingFunction[a ^ n, n, x, GenerateConditions -> True]Method (1)
VerifyConvergence (3)
设置 VerifyConvergence 为 False,将生成函数视为规范对象:
GeneratingFunction[2 ^ n, n, x, VerifyConvergence -> False]设置 VerifyConvergence 为 True,将验证收敛半径是非零的:
GeneratingFunction[2 ^ n, n, x, VerifyConvergence -> True]另外,设置 GenerateConditions 为 True,将显示收敛的条件:
GeneratingFunction[2 ^ n, n, x, VerifyConvergence -> True, GenerateConditions -> True]属性和关系 (5)
用 SeriesCoefficient 从它的生成函数得到序列:
GeneratingFunction[SeriesCoefficient[F[z], {z, 0, n}], n, z]GeneratingFunction[a ^ n Sin[n], n, z]SeriesCoefficient[%, {z, 0, n}]GeneratingFunction 计算一个无穷和:
GeneratingFunction[n ^ 2, n, z]Sum[n ^ 2 z ^ n, {n, 0, Infinity}]GeneratingFunction 和 ZTransform 可以互相表示:
{ZTransform[n ^ 2, n, z], GeneratingFunction[n ^ 2, n, 1 / z]}//Simplify{ZTransform[n ^ 2, n, 1 / z], GeneratingFunction[n ^ 2, n, z]}//SimplifyGeneratingFunction[a f[n] + b g[n], n, z]GeneratingFunction[f[n + 2], n, z]GeneratingFunction[Sum[f[k]g[k - n], {k, 0, n}], n, z]GeneratingFunction[n f[n], n, z]GeneratingFunction 与 ExponentialGeneratingFunction 密切相关:
{GeneratingFunction[n / n!, n, z], ExponentialGeneratingFunction[n, n, z]}{GeneratingFunction[n, n, z], ZTransform[n, n, 1 / z]}//Simplify{GeneratingFunction[n, n, Exp[I * ω]], FourierSequenceTransform[n UnitStep[n], n, ω]}可能存在的问题 (1)
GeneratingFunction 可能不会对参数的所有值都收敛:
{Sum[2 ^ n 1 ^ n, {n, 0, ∞}], GeneratingFunction[2 ^ n, n, 1]}GeneratingFunction[a ^ n, n, x]用 GenerateConditions 获取收敛区域:
GeneratingFunction[a ^ n, n, x, GenerateConditions -> True]巧妙范例 (1)
flist = {{UnitStep[n + 1 / 2], n, z}, {n ^ 2 + 2, n, z}, {1 / (2n + 1), n, z}, {Sin[a n], n, z}, {ChebyshevU[n, a], n, z}, {BernoulliB[n] / n!, n, z}, {a ^ n Sin[n], n, z}, {Mod[n, 7], n, z}, {Binomial[m, n], {m, n}, {u, v}}, {m / (n + 1), {m, n}, {u, v}}};Grid[Prepend[{#[[1]], GeneratingFunction@@#}& /@ flist, {f, "Generating Function"}], IconizedObject[«Grid options»]]//TraditionalForm相关链接
文本
Wolfram Research (2008),GeneratingFunction,Wolfram 语言函数,https://reference.wolfram.com/language/ref/GeneratingFunction.html.
CMS
Wolfram 语言. 2008. "GeneratingFunction." Wolfram 语言与系统参考资料中心. Wolfram Research. https://reference.wolfram.com/language/ref/GeneratingFunction.html.
APA
Wolfram 语言. (2008). GeneratingFunction. Wolfram 语言与系统参考资料中心. 追溯自 https://reference.wolfram.com/language/ref/GeneratingFunction.html 年
BibTeX
@misc{reference.wolfram_2026_generatingfunction, author="Wolfram Research", title="{GeneratingFunction}", year="2008", howpublished="\url{https://reference.wolfram.com/language/ref/GeneratingFunction.html}", note=[Accessed: 19-June-2026]}
BibLaTeX
@online{reference.wolfram_2026_generatingfunction, organization={Wolfram Research}, title={GeneratingFunction}, year={2008}, url={https://reference.wolfram.com/language/ref/GeneratingFunction.html}, note=[Accessed: 19-June-2026]}