backprop

\documentclass[border=0.1cm]{standalone}

\usepackage[utf8]{inputenc}
\usepackage{amsmath, amssymb, latexsym}
\usepackage{tikz}
\usetikzlibrary{decorations.pathreplacing}


\begin{document}

	\centering
	\begin{tikzpicture}[shorten >=1pt]
	\tikzstyle{unit}=[draw,shape=circle,minimum size =1.4cm]
	
	\node[unit](i) at (0,1){$y_i^{(l)}$};
	\node[unit](k1) at (3,2){$y_1^{(l+1)}$};
	\node at (3, 1){$\vdots$};
	\node[unit](km) at (3,-0.25){$y_m^{(l+1)}$};
	
	\node at (1.25,2.25){$\delta_1^{(l+1)}$};
	\node at (1.25,-0.5){$\delta_m^{(l+1)}$};
	
	\draw[->] (i) -- (k1);
	\draw[->] (i) -- (km);
	
	\draw[->,red,line width=0.05cm] (2,-0.25) -- (0.75,0.3);
	\draw[->,red,line width=0.05cm] (2,2) -- (0.75,1.6);
	\end{tikzpicture}

	\label{fig:error-backpropagation}
	
\end{document}