带缩进控制的多行方程

Question

我有以下多线方程，

\begin{equation} \label{eq:19}
\begin{split}
I_{1\to 1}(2)&=\tanh\Big(w^{ro}_{1,1}\cdot{h_1}^{x_1}(2) + w^{ro}_{2,1}\cdot{h_2}^{x_1}(2)+ w^{io}_{1,1}\cdot{x}_{1}(2)\Big) \\
&=\tanh\bigg(w^{ro}_{1,1}\cdot \Big( (1-\alpha) \cdot \alpha \cdot h_1^{x_1}(1) + \alpha \cdot \tanh \Big(w^{rr}_{1,1}\cdot h_1^{x_1}(1) + w^{rr}_{2,1}\cdot h_2^{x_1}(1) + w^{ir}_{1,1}\cdot x_1(2)\Big)\Big) \\
  &+ w^{ro}_{2,1} \cdot \Big((1-\alpha) \cdot \alpha \cdot h_2^{x_1}(1) + \alpha \cdot \tanh \Big(w^{rr}_{1,2}\cdot h_1^{x_1}(1) + w^{rr}_{2,2}\cdot h_2^{x_1}(1) + w^{ir}_{1,2}\cdot x_1(2)\Big)\Big) \\
  &+ w^{io}_{1,1}\cdot{x}_{1}(2) \bigg).
\end{split}
\end{equation}

我希望将以“+”开头的最后两行向右移动几个空格以获得更好的视觉效果。任何帮助都将不胜感激！

Answer 1

\documentclass[a4paper,landscape]{article}
\usepackage{geometry}
\usepackage{amsmath}

\begin{document}

qquad
\begin{equation} \label{eq:dontusenumbers-quad}
\begin{split}
I_{1\to 1}(2)&=\tanh\Bigl(w^{ro}_{1,1}\cdot{h_1}^{x_1}(2) + w^{ro}_{2,1}\cdot{h_2}^{x_1}(2)+ w^{io}_{1,1}\cdot{x}_{1}(2)\Bigr) \\
&=\tanh\biggl(w^{ro}_{1,1}\cdot \Bigl( (1-\alpha) \cdot \alpha \cdot h_1^{x_1}(1) + \alpha \cdot \tanh \Bigl(w^{rr}_{1,1}\cdot h_1^{x_1}(1) + w^{rr}_{2,1}\cdot h_2^{x_1}(1) + w^{ir}_{1,1}\cdot x_1(2)\Bigr)\Bigr) \\
  &\qquad+ w^{ro}_{2,1} \cdot \Bigl((1-\alpha) \cdot \alpha \cdot h_2^{x_1}(1) + \alpha \cdot \tanh \Bigl(w^{rr}_{1,2}\cdot h_1^{x_1}(1) + w^{rr}_{2,2}\cdot h_2^{x_1}(1) + w^{ir}_{1,2}\cdot x_1(2)\Bigr)\Bigr) \\
  &\qquad+ w^{io}_{1,1}\cdot{x}_{1}(2) \biggr).
\end{split}
\end{equation}

aligned
\begin{equation} \label{eq:dontusenumbers-aligned}
\begin{split}
I_{1\to 1}(2)&=\tanh\Bigl(w^{ro}_{1,1}\cdot{h_1}^{x_1}(2) + w^{ro}_{2,1}\cdot{h_2}^{x_1}(2)+ w^{io}_{1,1}\cdot{x}_{1}(2)\Bigr) \\
&=
\begin{aligned}[t]
\tanh\biggl(&w^{ro}_{1,1}\cdot \Bigl( (1-\alpha) \cdot \alpha \cdot h_1^{x_1}(1) + \alpha \cdot \tanh \Bigl(w^{rr}_{1,1}\cdot h_1^{x_1}(1) + w^{rr}_{2,1}\cdot h_2^{x_1}(1) + w^{ir}_{1,1}\cdot x_1(2)\Bigr)\Bigr) \\
  &+ w^{ro}_{2,1} \cdot \Bigl((1-\alpha) \cdot \alpha \cdot h_2^{x_1}(1) + \alpha \cdot \tanh \Big(w^{rr}_{1,2}\cdot h_1^{x_1}(1) + w^{rr}_{2,2}\cdot h_2^{x_1}(1) + w^{ir}_{1,2}\cdot x_1(2)\Bigr)\Bigr) \\
  &+ w^{io}_{1,1}\cdot{x}_{1}(2) \biggr).
\end{aligned}
\end{split}
\end{equation}
\end{document}