TikZ anchoring and relative positioning

Question

I have written a small tikz snippet that displays the diagram as I expect

\documentclass{standalone}
\usepackage{amsmath}
\usepackage{tikz}
\usetikzlibrary{shapes.arrows}
\usetikzlibrary{positioning}
\begin{document}

\begin{tikzpicture}[node distance=.15cm,>=latex]

\tikzstyle{myarr} = [draw, inner sep=5pt, fill=black!20, single arrow,single arrow head extend=0.1cm]
\tikzstyle{mylbl} = [inner sep=0pt, color=blue!70, text centered, text width=2cm]
\tikzstyle{mybox} = [draw, inner sep=5pt, text centered]

\node[mybox, text depth=2cm, text width=2cm] (corpus) at (0,0) {\textbf{Corpus}};
\node[myarr, single arrow head extend=0cm, single arrow tip angle=130, right=-1cm of corpus] (transformation) {Transformation};

% Is possible to resize the node to fit the whole content?
\node[mybox, text depth=1.75cm, text width=8.5cm, right=-1cm of transformation]  (embedding)  {\textbf{Embedding method}};

% UGLY HACK 1
\node[myarr ,single arrow head extend=0cm,single arrow tip angle=130, rotate=0, right=-1cm of corpus] (transformationhack) {Transformation};

\node[mylbl, right=of transformation] (sentence) {``I think ??? I am''};
\node[myarr, right=of sentence] (arrowa) {};
\node[mybox, minimum height=7ex, right=of arrowa] (cbow) {\textbf{CBOW}};
\node[myarr, right=of cbow] (arrowb) {};
\node[mylbl, right=of arrowb] (predict) {``therefore''};

% Why do I need a larger spacing here?
\node[myarr, rotate=-90, below=.35cm of embedding] (arrowc) {};

% east?
\node[mybox, text width=4cm, text depth=2.5cm, below=of arrowc.east] (embeddings) {\textbf{Word embeddings}};

% How to center this at center of (embeddings) without hand picking.
\node[] at (6.3,-3.80) (matrix) {%
$\begin{bmatrix}
0.12 & 0.59 & \cdots & 0.33 \\
0.48 & 0.02 & \cdots & 0.29 \\
\vdots & \vdots & \ddots & \vdots \\
0.32 & 0.74 & \cdots & 0.61
\end{bmatrix}$
};

\end{tikzpicture}
\end{document}

As shown in image below

But I'm still concerned about some "techniques" I have used to achieve these results. Hence I came here looking for ideas in how to improve the code (and design) quality.

First, since I want the "transform" arrow over the boxes I draw it twice, first time to work as a label to the second box (embedding) and the second to draw over the boxes. I didn't feel confortable with this approach. I labeled as UGLY HACK.

Second, I tried to break the node (Sentence) after the word ``think'' using the \\, but didn't work, to "fix" that, I have forced a text width of given size.

Third, If I add spacing, change text, or anything in the contents "inside" the (embedding) node, I need resize it. I know it makes sense, but I wish to know if there is a way to say: look, these objects are inside you, enlarge to fill, respect the inner separator, be elegant.

Fourth, why do I need a larger spacing in (arrowc), why it wont respect the global .15cm distance?

Fifth, why the (embeddings) [I know two box with very similar names, sorry] box needs to be is anchored to (arrowc.east) to correct placement, why not (arrowc.south)?

And lastly, how can I anchor my (matrix) node to the "center=of embeddings.center", instead to manually choose the position?

Best regards

PS: Of course, any overall improvements are always welcome.

Answer 1

For the ugly hack --simply draw your arrow after both boxes are drawn -- that way the arrow will cover the border of both boxes

\documentclass{standalone}
\usepackage{amsmath}
\usepackage{tikz}
\usetikzlibrary{shapes.arrows}
\usetikzlibrary{positioning}
\begin{document}
    
    \begin{tikzpicture}[node distance=.15cm,>=latex]
        
        \tikzstyle{myarr} = [draw, inner sep=5pt, fill=black!20, single arrow,single arrow head extend=0.1cm]
        \tikzstyle{mylbl} = [inner sep=0pt, color=blue!70, text centered, text width=2cm]
        \tikzstyle{mybox} = [draw, inner sep=5pt, text centered]
        
        \node[mybox, text depth=2cm, text width=2cm] (corpus) at (0,0) {\textbf{Corpus}};
        
        % Is possible to resize the node to fit the whole content?
        \node[mybox, text depth=1.75cm, text width=8.5cm, right=1cm of corpus]  (embedding)  {\textbf{Embedding method}};
        \node[myarr, single arrow head extend=0cm, single arrow tip angle=130, right=-1cm of corpus] (transformation) {Transformation};
        
        % UGLY HACK 1
%       \node[myarr ,single arrow head extend=0cm,single arrow tip angle=130, rotate=0, right=-1cm of corpus] (transformationhack) {Transformation};
        
        \node[mylbl, right=of transformation] (sentence) {``I think ??? I am''};
        \node[myarr, right=of sentence] (arrowa) {};
        \node[mybox, minimum height=7ex, right=of arrowa] (cbow) {\textbf{CBOW}};
        \node[myarr, right=of cbow] (arrowb) {};
        \node[mylbl, right=of arrowb] (predict) {``therefore''};
        
        % Why do I need a larger spacing here?
        \node[myarr, rotate=-90, below=.35cm of embedding] (arrowc) {};
        
        % east?
        \node[mybox, text width=4cm, text depth=2.5cm, below=of arrowc.east] (embeddings) {\textbf{Word embeddings}};
        
        % How to center this at center of (embeddings) without hand picking.
        \node[] at (6.3,-3.80) (matrix) {%
            $\begin{bmatrix}
                0.12 & 0.59 & \cdots & 0.33 \\
                0.48 & 0.02 & \cdots & 0.29 \\
                \vdots & \vdots & \ddots & \vdots \\
                0.32 & 0.74 & \cdots & 0.61
            \end{bmatrix}$
        };
        
    \end{tikzpicture}
\end{document}

EDIT --for the sentence break

Simply use align=left in the definition of label box as below

    \tikzstyle{mylbl} = [inner sep=0pt, color=blue!70, align=left ] 

Now you can use \\ to break the sentence-- off course the alignment will be off since there is a " in the first line but not in the second line so you can add a phantom " in the second line which will not be printed but will improve the alignment

    \node[mylbl, right=of transformation] (sentence) {``I think \\ \phantom{"}I am''};

\documentclass{standalone}
\usepackage{amsmath}
\usepackage{tikz}
\usetikzlibrary{shapes.arrows}
\usetikzlibrary{positioning}
\begin{document}
    
    \begin{tikzpicture}[node distance=.15cm,>=latex]
        
        \tikzstyle{myarr} = [draw, inner sep=5pt, fill=black!20, single arrow,single arrow head extend=0.1cm]
        \tikzstyle{mylbl} = [inner sep=0pt, color=blue!70, align=left ]
        \tikzstyle{mybox} = [draw, inner sep=5pt, text centered]
        
        \node[mybox, text depth=2cm, text width=2cm] (corpus) at (0,0) {\textbf{Corpus}};
        
        % Is possible to resize the node to fit the whole content?
        \node[mybox, text depth=1.75cm, text width=8.5cm, right=1cm of corpus]  (embedding)  {\textbf{Embedding method}};
        \node[myarr, single arrow head extend=0cm, single arrow tip angle=130, right=-1cm of corpus] (transformation) {Transformation};
        
        % UGLY HACK 1
%       \node[myarr ,single arrow head extend=0cm,single arrow tip angle=130, rotate=0, right=-1cm of corpus] (transformationhack) {Transformation};
        
        \node[mylbl, right=of transformation] (sentence) {``I think \\ \phantom{"}I am''};
        \node[myarr, right=of sentence] (arrowa) {};
        \node[mybox, minimum height=7ex, right=of arrowa] (cbow) {\textbf{CBOW}};
        \node[myarr, right=of cbow] (arrowb) {};
        \node[mylbl, right=of arrowb] (predict) {``therefore''};
        
        % Why do I need a larger spacing here?
        \node[myarr, rotate=-90, below=.35cm of embedding] (arrowc) {};
        
        % east?
        \node[mybox, text width=4cm, text depth=2.5cm, below=of arrowc.east] (embeddings) {\textbf{Word embeddings}};
        
        % How to center this at center of (embeddings) without hand picking.
        \node[] at (6.3,-3.80) (matrix) {%
            $\begin{bmatrix}
                0.12 & 0.59 & \cdots & 0.33 \\
                0.48 & 0.02 & \cdots & 0.29 \\
                \vdots & \vdots & \ddots & \vdots \\
                0.32 & 0.74 & \cdots & 0.61
            \end{bmatrix}$
        };
        
    \end{tikzpicture}
\end{document}

EDIT2 -- for the enlarge node

Use the tikzlibrary{fit} as below

   \node[draw=teal, dashed,ultra thick,  fit=(sentence) (arrowa)(arrowb) (cbow)(predict)] {};

This will auto enlarge if you add anything in the nodes inside

EDIT -- for arrowc.east

Anchors also get rotated when you rotate the arrow so east takes the place of south anchor when rotated -90

For the placement of matrix -- I again suggest fit library so that it can expand with the matrix

Your problems are related to choosing nodes from where to position is all

Complete MWE

\documentclass{standalone}
\usepackage{amsmath}
\usepackage{tikz}
\usetikzlibrary{shapes.arrows}
\usetikzlibrary{positioning,fit}
\begin{document}
    
    \begin{tikzpicture}[node distance=.15cm,>=latex]
        
        \tikzstyle{myarr} = [draw, inner sep=5pt, fill=black!20, single arrow,single arrow head extend=0.1cm]
        \tikzstyle{mylbl} = [inner sep=0pt, color=blue!70, align=left ]
        \tikzstyle{mybox} = [draw, inner sep=5pt, text centered]
        
        \node[mybox, text depth=2cm, text width=2cm] (corpus) at (0,0) {\textbf{Corpus}};
        
        % Is possible to resize the node to fit the whole content?
        \node[mybox, draw=none, text depth=1.75cm, text width=8.5cm, right=1cm of corpus]  (embedding)  {\textbf{Embedding method}};
        \node[myarr, single arrow head extend=0cm, single arrow tip angle=130, right=-1cm of corpus] (transformation) {Transformation};
        
        % UGLY HACK 1
%       \node[myarr ,single arrow head extend=0cm,single arrow tip angle=130, rotate=0, right=-1cm of corpus] (transformationhack) {Transformation};
        
        \node[mylbl, right=of transformation] (sentence) {``I think \\ \phantom{"}I am''};
        \node[myarr, right=of sentence] (arrowa) {};
        \node[mybox, minimum height=7ex, right=of arrowa] (cbow) {\textbf{CBOW}};
        \node[myarr, right=of cbow] (arrowb) {};
        \node[mylbl, right=of arrowb] (predict) {``therefore''};
        
        % Why do I need a larger spacing here?
        \node[myarr, rotate=-90, below=of embedding] (arrowc) {};
        
        % east?
        \node[mybox, draw=none,  below=of arrowc.east] (embeddings) {\textbf{Word embeddings}};
        
        % How to center this at center of (embeddings) without hand picking.
        \node[below=2cm of embedding]  (matrix) {%
            $\begin{bmatrix}
                0.12 & 0.59 & \cdots & 0.33 \\
                0.48 & 0.02 & \cdots & 0.29 \\
                \vdots & \vdots & \ddots & \vdots \\
                0.32 & 0.74 & \cdots & 0.61
            \end{bmatrix}$
        };
        \node[draw=teal, dashed,ultra thick,  fit=(matrix)(embeddings)] {};
        \node[draw=teal, dashed,ultra thick,  fit=(sentence) (arrowa)(arrowb) (cbow)(predict)] {};
    \end{tikzpicture}
\end{document}