如何绘制 Beta 分布的 pdf 曲线？

Question

我需要绘制两条已知形状参数的 pdf 曲线，用于投影仪演示。如果能得到一些建议，我将不胜感激。

Answer 1

正如 Bobyandbob 在在问题下方评论你可以采纳我的答案这里得到你所需要的。

总结一下那里给出的内容：
如果您已经安装，gnuplot您可以使用 PGFPlotsraw gnuplot函数来定义 beta 函数所需的函数，然后绘制由 PGFPlots 读取并用于绘图的数据文件。

% used PGFPlots v1.14
\documentclass[border=5pt]{standalone}
\usepackage{pgfplots}
    % define a command which stores all commands that are needed for every
    % `raw gnuplot' call
    \newcommand*\GnuplotDefs{
        % set number of samples
        set samples 51;
        %
        % define beta distribution function
        % (copied from <http://gnuplot.sourceforge.net/demo/prob.5.gnu>)
        Binv(p,q)=exp(lgamma(p+q)-lgamma(p)-lgamma(q));
        beta(x,p,q)=p<=0||q<=0?1/0:x<0||x>1?0.0:Binv(p,q)*x**(p-1.0)*(1.0-x)**(q-1.0);
    }
\begin{document}
\begin{tikzpicture}
        % define macros which are needed for the axis limits as well as for
        % setting the domain of calculation
        \pgfmathsetmacro{\xmin}{0}
        \pgfmathsetmacro{\xmax}{1}
    \begin{axis}[
        xmin=\xmin,
        xmax=\xmax,
        no markers,
    ]
        \addplot gnuplot [raw gnuplot] {
            % first call all the "common" definitions
            \GnuplotDefs
            % and then create the data tables
            % in GnuPlot `x` key is identical to PGFPlots `domain` key
            %
            % "plot" beta function
            plot [x=\xmin:\xmax] beta(x,1,1);
        };
        \addplot gnuplot [raw gnuplot] {
            \GnuplotDefs
            plot [x=\xmin:\xmax] beta(x,7,5);
        };
    \end{axis}
\end{tikzpicture}
\end{document}

Answer 2

pstricks一个带有及其模块的短代码pst-func，它定义了一个命令（使用开关（MiKTeX）或（TeX Live、MacTeX）\psBetaDist进行编译）：pdflatex--enable-write18-shell-escape

\documentclass[x11names, border=1pt]{standalone}

\usepackage{pst-func, pst-plot}
\usepackage{auto-pst-pdf}

\begin{document}

\psset{xunit=8cm, yunit=2cm}
\begin{pspicture*}(-1,-1)(1.1,3.1)
\psaxes[linecolor=LightSteelBlue3, tickcolor=LightSteelBlue3, ticksize=3pt -3pt, ticks=all, tickstyle=bottom, Dx=0.1, Dy=0.5, labelFontSize=\scriptstyle]{-}(0,0)(1.005,3.005)
\psBetaDist[linecolor=DarkGoldenrod1, alpha=1, beta=1]{0.005}{0.995}
\psBetaDist[linecolor=OliveDrab4, alpha=7, beta=5]{0.005}{0.995}
\end{pspicture*}

\end{document}