Simplification and Latexify Issues

[nathanrboyer]

I am trying to make a Quarto document to demonstrate solving simple symbolic equations.
I am getting the correct answer, but the expressions look a mess.

1. The equation eq display is not latexifying correctly.
   a. It is not in math font.
   b. The subscripts are shown with underscores.
2. The solution sol display shows the subscripts correctly, but ...
   a. sqrt is shown as "ssqrt" with an extra s for some reason
   b. There is a 1/2 pulled out front that makes no sense, even when I explicitly ask for simplify, expand, and simplify_fractions.

# Cell 1
using Symbolics, Nemo, Latexify
@variables v_f, v_i, y_f, y_i, a
eq = v_f^2 ~ v_i^2 + 2 * a * (y_f - y_i)
latexify(eq)

# Cell 2
sol = symbolic_solve(eq, v_f)
sol = simplify.(sol[1], expand=true, simplify_fractions=true)
latexify(sol)

# Cell 3
d = Dict(
    v_i => 20,
    v_f => 0,
    a => -32.2,
    y_i => 0,
    y_f => 6.2,
)
v_f_unique = substitute(sol, d)

[ChrisRackauckas]

I don't know what MIME type Quarto uses on its outputs. Do you know who I should ask?

[nathanrboyer]

EDITED:

I’m not sure. Maybe @jkrumbiegel or @MichaelHatherly?

I get the same rendering behavior for both in Pluto.

[MichaelHatherly]

I’m not sure. Maybe @jkrumbiegel or @MichaelHatherly?

Yeah, could be QNR or Quarto rendering issues there. If you convert the LaTeXString to a normal String are the characters the same between Quarto and Pluto.

[nathanrboyer]

EDITED:

The LatexStrings exactly match.

Pluto

\begin{equation}
\mathtt{v\_f}^{2} = 2 a \left( \mathtt{y\_f} - \mathtt{y\_i} \right) + \mathtt{v\_i}^{2}
\end{equation}

\begin{equation}
\frac{1}{2} \mathrm{ssqrt}\left( 8 a \mathtt{y_{f}} - 8 a \mathtt{y_{i}} + 4 \mathtt{v_{i}}^{2} \right)
\end{equation}

Quarto

\begin{equation}
\mathtt{v\_f}^{2} = 2 a \left( \mathtt{y\_f} - \mathtt{y\_i} \right) + \mathtt{v\_i}^{2}
\end{equation}

\begin{equation}
\frac{1}{2} \mathrm{ssqrt}\left( 8 a \mathtt{y_{f}} - 8 a \mathtt{y_{i}} + 4 \mathtt{v_{i}}^{2} \right)
\end{equation}

[MichaelHatherly]

what MIME type Quarto uses on its outputs

text/latex

The same code in Pluto shows eq correctly,

Here's the rendering of Pluto for the above example for me:

Which doesn't look the same as yours, odd.

Just directly doing that code in a REPL and pasting the resulting LaTeX representation into mathjax in a browser gives the following, which looks pretty much the same as the first image in this issue, so this doesn't appear to be caused by QNR or Quarto.

julia> using Symbolics, Nemo, Latexify
[ Info: Precompiling DistributedExt [075b2bf6-2807-5c02-93c4-9c66b4782582]

Welcome to Nemo version 0.49.1

Nemo comes with absolutely no warranty whatsoever

julia> @variables v_f, v_i, y_f, y_i, a
5-element Vector{Num}:
 v_f
 v_i
 y_f
 y_i
   a

julia> eq = v_f^2 ~ v_i^2 + 2 * a * (y_f - y_i)
v_f^2 ~ 2a*(y_f - y_i) + v_i^2
julia> latexify(eq)
L"\begin{equation}
\mathtt{v\_f}^{2} = 2 a \left( \mathtt{y\_f} - \mathtt{y\_i} \right) + \mathtt{v\_i}^{2}
\end{equation}
"

julia> sol = symbolic_solve(eq, v_f)
2-element Vector{SymbolicUtils.BasicSymbolic{Real}}:
 (1//2)*√((8//1)*a*y_f - (8//1)*a*y_i + (4//1)*(v_i^2))
 (-1//2)*√((8//1)*a*y_f - (8//1)*a*y_i + (4//1)*(v_i^2))

julia> sol = simplify.(sol[1], expand=true, simplify_fractions=true)
(1//2)*√((8//1)*a*y_f - (8//1)*a*y_i + (4//1)*(v_i^2))

julia> latexify(sol)
L"\begin{equation}
\frac{1}{2} \mathrm{ssqrt}\left( 8 a \mathtt{y_{f}} - 8 a \mathtt{y_{i}} + 4 \mathtt{v_{i}}^{2} \right)
\end{equation}
"

[MichaelHatherly]

Are the versions of all packages exactly the same in the Quarto and Pluto notebooks @nathanrboyer?

[nathanrboyer]

Okay, I had to force a Symbolics.jl update within the Pluto notebook for some reason. Error is gone now. I will update my above posts. Both are now using Symbolics v6.29.2.

[nathanrboyer]

Quarto and Pluto both produce the same LaTeXStrings and rendering behavior, so this is a Symbolics.jl or Latexify.jl issue.

eq looks good (in both Quarto and Pluto) on Latexify v0.15.21, but then symbolic_solve doesn't exist in Symbolics v5.14.1 to obtain sol.

\begin{equation}
v_{f}^{2} = 2 a \left( y_{f} - y_{i} \right) + v_{i}^{2}
\end{equation}

Poor renderings of eq and sol from the original post occur (in both Quarto and Pluto) using the lastest package versions: Latexify v0.16.6 and Symbolics v6.29.2.

[ChrisRackauckas]

We haven't touched the latexify writing in like a year, so @gustaphe maybe this is a Latexify change?

[nathanrboyer]

The 1/2 being pulled out front in sol is a Symbolics.jl issue though.

[ChrisRackauckas]

I'm not worried about that here, that's a separate issue. Let's focus on just one thing.

[gustaphe]

The latexify part of this should not be hard to fix, but I need a bit of input. Is ssqrt a thing outside Symbolics.jl? Like, I could either hardcode the recipe in Symbolics/src/latexify_recipes.jl to treat ssqrt as sqrt, or Latexify could do the same. It's just a question of whether ssqrt means something even to someone who is not using Symbolics.

[gustaphe]

Okay, I'm leaning towards adding :ssqrt as a synonym for :sqrt (, :scbrt, :slog) in Latexify - there's no risk of confusion there, and the Symbolics latex recipe is very dense for someone unfamiliar with the Symbolics package.

For the bug in eq, I guess #1385 would at least offer a workaround? If someone who understands the Symbolics recipes wants to fix this more automatically, I suggest looking at how Latexify treats f_x(1) vs abc_x(1), specifically Latexify/src/latexoperation.jl:278, the convert_subscript function.