用箭头将圆圈添加到 tikz 图形中

Question

继续提供出色的答案： 改变 tikz 图形以拥有更多块

我想修改此图并添加一个带有箭头和文本的“加法器”节点，并在下方箭头上方的入口附近添加文本（参见图中的“nn”文本）。新图应如下所示：

Answer 1

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{positioning,arrows.meta}

\begin{document}

\tikzset{%
  block/.style = { draw,
                   thick,
                   rectangle,
                   minimum height = 3em,
                   fill=white,
                   align=center
   },
   wide block/.style = {
                   block,
                   text width=2.5cm,
                   minimum width = 8em,
   },
   adder/.style={draw,circle}
}

  \begin{tikzpicture}[auto, thick, node distance=2cm, >=Triangle]
    \node[wide block] (glamor) {glamor};
    \node[wide block, right = 15mm of glamor] (trainer) {trainer};
    \node[block, below=10mm of glamor.south east](M){M};
    \node[block, below=10mm of trainer.south west](L){L};
    \node[adder](A1) at (M-|glamor.south west){+};
    \draw[<-](glamor.west) --node[above]{$mm$} ++(-2,0);
    \draw[->](glamor) -- node {$mnn$} (trainer);
    \draw[->](trainer.east) -- node[name=y]{$ppx$} ++ (2,0);
    \draw[->,rounded corners](trainer.east) -- ++(1,0) |- (L);
    \draw[->](L)--(M);
    \draw[<-, rounded corners]([yshift=1mm]glamor.south west) 
           -- ++(-1,0) node[above right]{$nn$}  |- (A1);
    \draw (A1) -- (M);
    \draw[<-] (A1.south) -- ++ (0,-5mm) node[pos=0.7,left]{$w$};
  \end{tikzpicture}

\end{document}