LaTeX renderer#
LatexRenderer produces a LaTeX fragment to paste into the body of a .tex document.
from handcalcs.renderers import LatexRenderer
## Bolt group
# Shear is shared equally between the bolts.
n = 4 # bolts
V_f = 120 # kN
V_b = V_f / n
if V_b <= 40:
status = "OK"
Bolt group
Shear is shared equally between the bolts.
Since \(\bigl(V_{b} \le 40\bigr) \rightarrow \bigl(30 \le 40\bigr)\) is True:
\[\begin{aligned} \mathrm{status} &= \text{``OK''} \end{aligned}\]
\section*{Bolt group}
\noindent Shear is shared equally between the bolts.
\medskip
\noindent$\displaystyle
\begin{aligned}[t]
n &= 4 \quad\text{(bolts)} \\
V_{f} &= 120 \quad\text{(kN)} \\
V_{b} &= \frac{V_{f}}{n} = \frac{120}{4} = 30
\end{aligned}$
\medskip
\noindent Since $\bigl(V_{b} \le 40\bigr) \rightarrow \bigl(30 \le 40\bigr)$ is True:
\begin{list}{}{\setlength{\leftmargin}{1.5em}}\item[]
\medskip
\noindent$\displaystyle
\begin{aligned}[t]
\mathrm{status} &= \text{``OK''}
\end{aligned}$
\medskip
\end{list}
A fuller example#
Headings and prose, a parameter grid, a long equation broken with -m, a governing
branch, and a pass/fail check, all in one calculation:
## Steel beam
# Lateral-torsional buckling resistance of a simply supported span.
# hc: -h -c 3
E = 200000 # MPa
G = 77000 # MPa
L = 6000 # mm
I_y = 160e6 # mm⁴
J = 133e3 # mm⁴
C_w = 200e9 # mm⁶
### Elastic critical moment
M_u = pi / L * sqrt(E * I_y * G * J + (pi * E / L)**2 * I_y * C_w) # hc: -m
M_p = 285e6 # N mm
if M_u > 0.67 * M_p:
M_r = 1.15 * 0.9 * M_p * (1 - 0.28 * M_p / M_u) # hc: -m
else:
M_r = 0.9 * M_u
M_f = 210e6 # N mm
M_f <= M_r # hc: --check
Steel beam
Lateral-torsional buckling resistance of a simply supported span.
Elastic critical moment
Since \(\bigl(M_{u} > 0.67 \cdot M_{p}\bigr) \rightarrow \bigl(4.3134 \times 10^{8} > 0.67 \cdot 2.85 \times 10^{8}\bigr)\) is True:
\[\begin{aligned} M_{r} &= 1.15 \cdot 0.9 \cdot M_{p} \cdot \left(1 - \frac{0.28 \cdot M_{p}}{M_{u}}\right) = 1.15 \cdot 0.9 \cdot 2.85 \times 10^{8} \cdot \left(1 - \frac{0.28 \cdot 2.85 \times 10^{8}}{4.3134 \times 10^{8}}\right) = 2.404 \times 10^{8} \end{aligned}\]
\section*{Steel beam}
\noindent Lateral-torsional buckling resistance of a simply supported span.
\medskip
\noindent$\displaystyle
\begin{aligned}[t]
E &= 200000 \; \text{(MPa)} \qquad &G &= 77000 \; \text{(MPa)} \qquad &L &= 6000 \; \text{(mm)} \\
I_{y} &= 1.6 \times 10^{8} \; \text{(mm⁴)} \qquad &J &= 1.33 \times 10^{5} \; \text{(mm⁴)} \qquad &C_{w} &= 2 \times 10^{11} \; \text{(mm⁶)}
\end{aligned}$
\medskip
\subsection*{Elastic critical moment}
\medskip
\noindent$\displaystyle
\begin{aligned}[t]
M_{u} &= \frac{\pi}{L} \cdot \sqrt{E \cdot I_{y} \cdot G \cdot J + \left(\frac{\pi \cdot E}{L}\right)^{2} \cdot I_{y} \cdot C_{w}} = \frac{3.1416}{6000} \cdot \sqrt{200000 \cdot 1.6 \times 10^{8} \cdot 77000 \cdot 1.33 \times 10^{5} + \left(\frac{3.1416 \cdot 200000}{6000}\right)^{2} \cdot 1.6 \times 10^{8} \cdot 2 \times 10^{11}} = 4.3134 \times 10^{8} \\
M_{p} &= 2.85 \times 10^{8} \quad\text{(N mm)}
\end{aligned}$
\medskip
\noindent Since $\bigl(M_{u} > 0.67 \cdot M_{p}\bigr) \rightarrow \bigl(4.3134 \times 10^{8} > 0.67 \cdot 2.85 \times 10^{8}\bigr)$ is True:
\begin{list}{}{\setlength{\leftmargin}{1.5em}}\item[]
\medskip
\noindent$\displaystyle
\begin{aligned}[t]
M_{r} &= 1.15 \cdot 0.9 \cdot M_{p} \cdot \left(1 - \frac{0.28 \cdot M_{p}}{M_{u}}\right) = 1.15 \cdot 0.9 \cdot 2.85 \times 10^{8} \cdot \left(1 - \frac{0.28 \cdot 2.85 \times 10^{8}}{4.3134 \times 10^{8}}\right) = 2.404 \times 10^{8}
\end{aligned}$
\medskip
\end{list}
\medskip
\noindent$\displaystyle
\begin{aligned}[t]
M_{f} &= 2.1 \times 10^{8} \quad\text{(N mm)} \\
M_{f} \le M_{r} &= 2.1 \times 10^{8} \le 2.404 \times 10^{8}\quad{\color{green}\checkmark}
\end{aligned}$
\medskip
Using the output#
To get a document you can compile straight away, give a destination:
HandCalcs(LatexRenderer())(pathlib.Path("calcs/bolts.py"), destination="bolts.tex")
The file is the output wrapped in the renderer’s preamble and postamble: an
article that loads the packages below. Change them on the renderer for your own
document class (see Writing a file).
Without a destination, the output is a fragment for the body of a document. It needs
the amsmath package, plus amssymb and xcolor for the marks of
--check lines. A minimal document:
\documentclass{article}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{xcolor}
\begin{document}
% paste or \input the handcalcs output here
\end{document}
A common pattern is to write each calculation to its own file and \input it:
import pathlib
from handcalcs import HandCalcs
from handcalcs.renderers import LatexRenderer
tex = HandCalcs(LatexRenderer())(pathlib.Path("calcs/bolts.py"))
pathlib.Path("report/bolts.tex").write_text(tex)
\input{bolts.tex}
In Jupyter, %hc_default_renderer latex displays the output with
IPython.display.Latex, which renders the math but not the text-mode commands
(\section*, \noindent, \medskip). Use the Markdown renderer for
notebooks.
Output structure#
Source |
LaTeX |
|---|---|
|
|
Comment lines |
A |
A run of calculation lines |
One flush-left |
Parameter grid |
An |
|
|
|
Indented with a |
Math conventions#
Names: Greek letter names become Greek letters (
alpha→ \(\alpha\),Gamma→ \(\Gamma\);lamborlambda_gives \(\lambda\) sincelambdais a Python keyword), and so do Unicode letters (ΔH→ \(\Delta H\), which also compiles under pdflatex) and a Greek name before an uppercase letter or digit (DeltaH→ \(\Delta H\))._starts a subscript and each further_adds one after a comma (N_pl_Rd→ \(N_{\mathrm{pl,Rd}}\)); neighbouring upright words share one\mathrm{}. Multi-letter words are set upright (class_section→ \(\mathrm{class}_{\mathrm{section}}\)).__is a space and___a literal underscore.hat,bar,dot,ddot,primeandstardecorate the part before them (x_hat→ \(\hat{x}\),M_star→ \(M^{*}\)). See naming variables.Operators:
*→ \(\cdot\),/→ a fraction,**→ a superscript,//→ a fraction in floor brackets,%→ \(\bmod\),<=→ \(\le\).Functions:
sqrt→ a radical;floor,ceil→ brackets;sin,cos,expand the other trigonometric and hyperbolic functions → their operators; any other function by its name, upright (\operatorname).Numbers: scientific notation is written as \(\times 10^{n}\);
inf→ \(\infty\).Collections longer than 10 items show their first and last three items around \(\ldots\).
Customizing#
The document structure is set by class attributes (MATH_OPEN, MATH_CLOSE,
HEADINGS, BLOCK_OPEN, COMMENT_OPEN, …) and the symbol tables OPERATOR_SYMBOLS and
MATH_FUNCS. Change them in a subclass; see
LaTeX and Markdown tokens.