equation - Missing { inserted

Question

I am getting the error message Missing insert { when using the below mathematical equation. I have no spaces between the equation so not sure where is the issue. Thanks

\begin{equation}
MAE = \frac{1}{n}\sum_{i=1}^{n}|{y}-{y^_j}|
\end{equation}
\begin{equation}
RMSE = \sqrt{\frac{1}{n}\sum_{i=1}^{n}({y}-{y^_j})^2}
\end{equation}

Unrelated, but you don't need {} around y nor around y^j or y_j. Also, you shouldn't have two consecutive equation environments (it's not an error, but it doesn't look right - look into gather or align). — Teepeemm, Aug 25 '20 at 14:48
I am trying to represent the above equations. It is a subscript. — Browed1983, Aug 25 '20 at 14:50
@egreg your answer has got rid of the error message. Thanks for everyone's help. — Browed1983, Aug 25 '20 at 14:56
One more thing no one has mentioned, you want to write, e.g., \mathrm{RMSE} — Don Hosek, Aug 25 '20 at 15:44

score 1 · Accepted Answer · answered Aug 25 '20 at 15:02

1

commath package is for absuse (matter of tastes, irrelevant).

\documentclass{article}
\usepackage{amsmath}
\usepackage{commath}
\begin{document}
\begin{equation}
    MAE = \frac{1}{n}\sum\limits_{j=1}^n\abs{y_j - \hat{y}_j}
\end{equation}
\begin{equation}
    RMSE = \sqrt{\frac{1}{n}\sum\limits_{j=1}^n (y_j - \hat{y}_j)^2}
\end{equation}
\end{document}

Result:

answered Aug 25 '20 at 15:02

Blooment

666

please don't recommend commath, it is completely broken – David Carlisle Aug 25 '20 at 15:35
@DavidCarlisle Thanks for the advice. Is there another package that includes \abs and \norm? – Blooment Aug 25 '20 at 15:38
1

mathtools would let you do \newcommand*\abs[1]{\lvert#1\rvert} \newcommand*\norm[1]{\lVert#1\rVert} (examples copied from texdoc mathtools) – David Carlisle Aug 25 '20 at 15:44

equation - Missing { inserted

1 Answers1