# Demo of admonition styles in DocOnce

H. P. Langtangen

Date: Oct 5, 2015

Summary. This note demonstrates how admonitions look like in the output format ipynb.

# The four main types of admonitions

Key options when compiling this document were

``    --ipynb_admon=quote``

Division by zero is illegal!

Most math systems will give fatal errors if you divide by zero.

``````    Terminal> python -c 'print 4/0'
Traceback (most recent call last):
File "<string>", line 1, in <module>
ZeroDivisionError: integer division or modulo by zero``````

You should therefore be very careful with all expressions that may result in division by zero. In Python, you can use a `try-except` clause to test if some expression gives a `ZeroDivisionError` exception and take appropriate actions. One example of a numerical method where division by zero can cause problems is Newton's methods of finding solutions to algebraic equations \$f(x)=0\$. In that algorithm, there is a division by \$f'(x)\$.

Question.

What are the admon options for `doconce format html`?

Summary.

The most popular methods for solving algebraic equations

\$\$ f(x) = 0 \$\$

are

• Newton's method

• The Bisection method

• The Secant method

• The Fixed-Point method (\$f(x) = x - g(x)\$)

Of these, Newton's method is fastest, the Bisection method is the most reliable, the Secant method is a simplified Newton method, and the Fixed-Point method is obviously very problem dependent in its behavior since the user has the define the \$g\$ function.

Tip: follow well-established conventions for variable names!

For example, in Python, variable and function names use lower case letters separated by underscore, as in `vibration_with_damping` (while Java typically would have `vibrationWithDamping`). Class names apply cap words, as in `ProblemClass`.

The four main admons are warning, notice, question, and summary.

# The block, quote and plain box environment

DocOnce features a `block` environment with or without title.

Blocks are often used in slides to frame a collection of things.

Block with title.

Blocks can contain text, math, code, figures, movies.

Here is a quote environment (`quote`):

Sayre's law states that "in any dispute the intensity of feeling is inversely proportional to the value of the issues at stake." By way of corollary, it adds: "That is why academic politics are so bitter." Source: wikipedia

Boxes are very simple frames (without any icons, background color, or stash, except for a shadow) used for important results like

Box.

The world most famous equation:

\$\$ E = mc^2 \$\$