Added multiline_latex to more easily print multiline equations #15944

oscargus · 2019-02-08T11:56:06Z

References to other Issues or PRs

Inspired by #3001

Brief description of what is fixed or changed

A new function multiline_latex is added to more easily split multiline equations.

It is simply based on the number of addition/subtraction terms and one can limit the number of terms per line.

Both align* and eqnarray can be used. I was thinking of adding IEEEeqnarray which is better, but then it may not be that regularly used and I couldn't really figure out parameter settings etc to make sense.

Other comments

Release Notes

printing
- New function multiline_latex which simplifies generating code for long expressions

sympy-bot · 2019-02-08T11:56:17Z

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- New function multiline_latex which simplifies generating code for long expressions (#15944 by @oscargus)

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#### References to other Issues or PRs
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Inspired by #3001

#### Brief description of what is fixed or changed
A new function `multiline_latex` is added to more easily split multiline equations.

It is simply based on the number of addition/subtraction terms and one can limit the number of terms per line.

Both `align*` and `eqnarray` can be used. I was thinking of adding `IEEEeqnarray` which is better, but then it may not be that regularly used and I couldn't really figure out parameter settings etc to make sense.

#### Other comments


#### Release Notes

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* printing
   * New function `multiline_latex` which simplifies generating code for long expressions
<!-- END RELEASE NOTES -->

Update

The release notes on the wiki have been updated.

jksuom · 2019-02-08T12:54:40Z

I would prefer having use_eqnarray False by default. It seems that the amstex environments produce better spacing.

\begin{align*}
  x^2+y^2 &= z^2 \\
  x^3+y^3 &< z^3
\end{align*}

\begin{eqnarray}
  x^2+y^2 &=& z^2 \\
  x^3+y^3 &<& z^3
\end{eqnarray}

jksuom · 2019-02-08T13:06:06Z

I finally succeeded in uploading an image.

oscargus · 2019-02-08T13:55:46Z

I agree with your conclusions in your example. I used beamer and there the conclusion was the opposite:

Now, admittedly, that is not a good reference. I'll try out a few more realistic ones and get back, but that was really the reason I even started to look at something different than align* (which was used in the original code).

oscarbenjamin · 2019-02-08T17:48:09Z

I thought eqnarray was considered obsolete: https://tex.stackexchange.com/questions/196/eqnarray-vs-align

oscargus · 2019-02-11T21:15:22Z

I wasn't aware that eqnarray has been that deprecated recently...

Anyway, I changed it to align* as default and also added IEEEeqnarray as an option.

oscargus · 2019-02-12T11:36:24Z

sympy/printing/latex.py

+
+    environment : "string", optional
+        Which LaTeX wnvironment to use for the output. Options are "align*"
+        (default), "eqnarray", and "IEEEeqnarray". Note the only the first


Shuold be "that" instead of "the". Will fix in the next commit, but waiting for other review comments before running a new test...

oscargus · 2019-02-12T11:37:13Z

sympy/printing/latex.py

+    terms_per_line : integer, optional
+        Number of terms per line to print. Default is 1.
+
+    environment : "string", optional


Gah! Should be string, not "string". As below.

oscarbenjamin · 2019-02-20T00:15:39Z

sympy/printing/latex.py

+
+    # Based on code from https://github.com/sympy/sympy/issues/3001
+    l = LatexPrinter(**settings)
+    if environment.lower().startswith('e'):


How about if environment == 'eqnarray' (same below)?

I was thinking about that, but then one need to type it correctly and considering that the alternatives are eqnarray, IEEEeqnarray, and array* it made sense (to me), to have a more "sloppy" checking of alternatives so that array and ieeeeqnarray also works.

Clearly, I mean align*, not array*

I don't see the advantage of sloppy checking. It's better to list the possibilities in the docstring then someone can get it right first time they write their code. Allowing anything that starts with e here leads to a backward compatibility problem if you ever decide to add another environment that begins with e.

OK! Should it be case sensitive or not?

I would go case-sensitive. I can see that you have already listed the 3 possibilities in the docstring so I'd go with that. Also these are the names of LaTeX environments which are case-sensitive.

oscarbenjamin · 2019-02-20T00:16:54Z

sympy/printing/latex.py

+        nonumber = r'\nonumber'
+        end_term = '\n\\end{IEEEeqnarray}'
+        doubleet = True
+    else:


Maybe the else could be an error after all correct cases are handled

Yes, that may be an idea.

oscarbenjamin · 2019-02-20T00:18:00Z

sympy/printing/latex.py

+        term = terms[i]
+        term_start = ''
+        term_end = r''
+        sign = r'+'


I don't understand why the above are raw strings (no big deal...)

Probably copy-paste or that they initially included things where it was needed... Makes sense to remove it.

oscarbenjamin · 2019-02-20T00:20:58Z

sympy/printing/latex.py

+    \end{eqnarray}
+
+    Using "IEEEeqnarray":
+    \begin{IEEEeqnarray}{rCl}


Is there a missing print here?

Yes. Thanks!

oscarbenjamin

I left a couple of comments. Your own comments also seemed reasonable

oscargus · 2019-02-20T08:43:44Z

Thanks for the review @oscarbenjamin ! I'll update it eventually.

… termsperline

oscargus · 2019-02-20T13:02:58Z

Comments fixed (apart from the sloppy environment detection).

oscarbenjamin · 2019-02-22T01:25:59Z

sympy/printing/latex.py

+    & & - \cos{\left(\log{\left(y \right)} \right)}
+    \end{eqnarray}
+
+    Using "IEEEeqnarray":


Should this be double quotes or backticks like above?

oscarbenjamin · 2019-02-22T01:32:54Z

sympy/printing/latex.py

+def multiline_latex(lhs, rhs, terms_per_line=1, environment="align", use_dots=False, **settings):
+    r"""
+    This function generates a LaTeX equation with a multiline right-hand side
+    in either an ``eqnarray`` or ``align*`` environment.


Below you list 3 environments including IEEEeqnarray but here only the other two.

oscarbenjamin

I've left comments but otherwise good.

oscargus · 2019-02-22T06:59:19Z

Good comments! Will fix.

oscargus · 2019-03-14T08:48:07Z

I have merged with current master (fixes done since long, but didn't comment on that).

oscarbenjamin · 2019-04-28T23:04:54Z

+1 to merge if you're finished with it.

oscargus · 2019-05-02T08:00:04Z

OK! I merge it then!

moorepants · 2022-02-13T15:08:56Z

Is there a way to enable this with init_printing()?

moorepants · 2022-02-13T15:14:09Z

I tried init_printing(latex_printer=multiline_latex) naively, but that fails with:

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
File ~/miniconda/envs/multibody-book/lib/python3.10/site-packages/IPython/core/formatters.py:343, in BaseFormatter.__call__(self, obj)
    341     method = get_real_method(obj, self.print_method)
    342     if method is not None:
--> 343         return method()
    344     return None
    345 else:

File ~/miniconda/envs/multibody-book/lib/python3.10/site-packages/sympy/interactive/printing.py:226, in _init_ipython_printing.<locals>._print_latex_text(o)
    222 """
    223 A function to generate the latex representation of sympy expressions.
    224 """
    225 if _can_print(o):
--> 226     s = latex(o, mode=latex_mode, **settings)
    227     if latex_mode == 'plain':
    228         return '$\\displaystyle %s$' % s

TypeError: multiline_latex() missing 1 required positional argument: 'rhs'

Added multiline_latex to more easily print multiline equations

35fcadd

oscargus added the printing label Feb 8, 2019

oscargus added 2 commits February 11, 2019 22:06

Made align* default and added IEEEeqnarray

275bc90

Updated documentation examples

3fca9a4

oscargus commented Feb 12, 2019

View reviewed changes

oscargus added the printing.latex label Feb 13, 2019

Merge branch 'master' into termsperline

288c630

oscarbenjamin reviewed Feb 20, 2019

View reviewed changes

oscargus added 3 commits February 20, 2019 12:37

Updated based on review comments

084e472

Merge branch 'termsperline' of https://github.com/oscargus/sympy into…

35d7cd9

… termsperline

Fixed failing doctest

cf7f40b

Using complete environment names as per request

b74bc04

oscarbenjamin reviewed Feb 22, 2019

View reviewed changes

Merge branch 'master' into termsperline

9543773

oscargus added 2 commits March 7, 2019 09:09

Fixed review comments

6374251

Merge with master, resolved conflicts

c207a0d

oscarbenjamin mentioned this pull request Apr 28, 2019

sympy function to display only certain number of terms per line for latex #3001

Closed

oscargus merged commit 9013298 into sympy:master May 2, 2019

oscargus deleted the termsperline branch May 2, 2019 08:00

moorepants mentioned this pull request Feb 13, 2022

init_printing() kwarg wrap_line should wrap long latex expressions #23071

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Added multiline_latex to more easily print multiline equations #15944

Added multiline_latex to more easily print multiline equations #15944

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oscargus commented Feb 8, 2019

References to other Issues or PRs

Brief description of what is fixed or changed

Other comments

Release Notes

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