[SOLVED] align equations with latex

Faki · 04-22-2022, 03:05 PM

I want to align equations and called `flalign`.

This gets me

Code:

 : LaTeX Error: Environment flalign undefined.

What else can I try for aligning equations. Here is the implementation that failed.

Code:

\begin{equation}
\begin{flalign*}
  f(u) & =\sum_{j=1}^{n} x_jf(u_j)&\\
       & =\sum_{j=1}^{n} x_j \sum_{i=1}^{m} a_{ij}v_i&\\
       & =\sum_{j=1}^{n} \sum_{i=1}^{m} a_{ij}x_jv_i
\end{flalign}
\end{equation}

TB0ne · 04-22-2022, 03:11 PM

Quote:

Originally Posted by Faki

I want to align equations and called `flalign`.
This gets me

Code:

 : LaTeX Error: Environment flalign undefined.

What else can I try for aligning equations. Here is the implementation that failed.

Code:

\begin{flalign*}
  f(u) & =\sum_{j=1}^{n} x_jf(u_j)&\\
       & =\sum_{j=1}^{n} x_j \sum_{i=1}^{m} a_{ij}v_i&\\
       & =\sum_{j=1}^{n} \sum_{i=1}^{m} a_{ij}x_jv_i
\end{flalign}

Related to this, presumably??
https://www.linuxquestions.org/quest...es-4175711028/

Again, may want to look up the error(s), and read the docs:
https://www.overleaf.com/learn/latex..._XXX_undefined

Faki · 04-22-2022, 03:54 PM

I want to align without using amsmath. The other question you mention was about texinfo which only accepts tex syntax rather than latex.

Faki · 04-22-2022, 04:01 PM

Have also tried align and split. That also failed.

TB0ne · 04-22-2022, 04:35 PM

Quote:

Originally Posted by Faki

I want to align without using amsmath. The other question you mention was about texinfo which only accepts tex syntax rather than latex.

...and...

Quote:

Originally Posted by Faki

Have also tried align and split. That also failed.

As with your other thread, you provide no details. Saying "also failed" says nothing, and you don't say WHY you don't want to use amsmath either, what version/distros of things you're using, etc.

Again: you were given a link to the documentation, along with a specific link to your exact error. Did you read/follow it??

Faki · 04-22-2022, 04:42 PM

I am using Ubuntu 18.04 LTS. And TeX 3.14159265 (TeX Live 2017/Debian).

When using multiline, align, aligned, flalign, I get

Code:

: LaTeX Error: Environment undefined.

Is there no built-in equation alignment in latex? Many things I have read from documentation always relates to amsmath, rather that built-in features in latex.

computersavvy · 04-22-2022, 08:40 PM

Quote:

Originally Posted by Faki

When using multiline, align, aligned, flalign, I get

Code:

: LaTeX Error: Environment undefined.

This really tells us nothing. What is the command structure used (code) for each of those, and exactly what are the messages.
Each of those functions has its own syntax for calling and returning and you have to satisfy the syntax when calling them, as well as the environment.

I don't use Tex, LaTex, etc but coding experience tells me you are not using the proper structure of environment and code for that error to pop up.

rnturn · 04-22-2022, 11:19 PM

Quote:

Originally Posted by Faki

I want to align equations and called `flalign`.

This gets me

Code:

 : LaTeX Error: Environment flalign undefined.

What else can I try for aligning equations. Here is the implementation that failed.

Code:

\begin{equation}
\begin{flalign*}
  f(u) & =\sum_{j=1}^{n} x_jf(u_j)&\\
       & =\sum_{j=1}^{n} x_j \sum_{i=1}^{m} a_{ij}v_i&\\
       & =\sum_{j=1}^{n} \sum_{i=1}^{m} a_{ij}x_jv_i
\end{flalign}
\end{equation}

I got it to work but:

Comment out the "equation" environment. When I have that uncommented, I get an error message squawking about nested equation environments. The equations, as written, don't seem to want to work in the "equation" environment, anyway, so I'd simply stick with "flalign/flalign*".
The "flalign" error has to do with you beginning an "flalign*" environment but ending it with "flalign" instead of "flalign*". ("flalign" is a prefect acceptable environment but you can't mix 'em in the same set of equations.)
I thought that those ampersands before the double backslashes might be a problem. Looks like is affects the indentation of the equations. Works without it as well (but indented from the left margin a bit). Use them or lose them; your call on style. (Hey! I learned something today!)

(Love seeing people using LaTeX.)

HTH...

TB0ne · 04-23-2022, 09:11 AM

Quote:

Originally Posted by Faki

I am using Ubuntu 18.04 LTS. And TeX 3.14159265 (TeX Live 2017/Debian). When using multiline, align, aligned, flalign, I get

Code:

: LaTeX Error: Environment undefined.

Is there no built-in equation alignment in latex? Many things I have read from documentation always relates to amsmath, rather that built-in features in latex.

Again, *WHY* don't you want to use amsmath?? What is the problem in using it??

And you were given a link to latex docs, which deal with the error, tell you what causes it, and how to fix it. While it does mention amsmath, it is as an EXAMPLE...in your case, replace it with what you ARE missing and/or how it's written.

Faki · 04-23-2022, 10:14 AM

Have found that AMS-LaTeX is included as part of the LaTeX collection, and one does not have to download or install it separately. So it is now ok to use it. Thank you so very much. Noticed that the problem was with &\\, which needs to be replaced with \cr