# diofant/diofant

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# Printing

As we have already seen, Diofant can pretty print its output using Unicode characters. This is a short introduction to the most common printing options available in Diofant. The most common ones are

In addition to these, there are also "printers" that can output Diofant objects to code, such as C, Fortran, or Mathematica.

Best printer is enabled automatically for interactive session (i.e. LaTeX in the IPython notebooks, pretty printer in the IPython console or str printer in the Python console). If you want manually configure pretty printing, please use the :func:~diofant.interactive.printing.init_printing function.

Lets take this simple expression

>>> expr = Integral(sqrt(1/x), x)

and try several available printers.

## Str

To get a string form of an expression, use :class:str. This is also the form that is produced by :func:print. String forms are designed to be easy to read and mostly to be in a form that is a correct Python syntax so that it can be copied and pasted.

>>> str(expr)
'Integral(sqrt(1/x), x)'
>>> print(expr)
Integral(sqrt(1/x), x)

## Repr

The repr form of an expression is designed to show the exact form of an expression, it would yield an object with the same value when passed to :func:eval. To get it, use :func:repr.

>>> repr(expr)
"Integral(Pow(Pow(Symbol('x'), Integer(-1)), Rational(1, 2)), Tuple(Symbol('x')))"

The repr form is mostly useful for understanding how an expression is built internally.

## 2D Pretty Printer

A two-dimensional (2D) textual representation of the expression can be obtained with :func:~diofant.printing.pretty.pretty.pretty.

>>> pretty(expr)
'⌠           \n⎮     ___   \n⎮    ╱ 1    \n⎮   ╱  ─  dx\n⎮ ╲╱   x    \n⌡           '
>>> print(_)
⌠
⎮     ___
⎮    ╱ 1
⎮   ╱  ─  dx
⎮ ╲╱   x
⌡

Note

Unicode pretty-printing is enabled by default in the IPython terminal frontend.

You can pass use_unicode=False to use ASCII symbols.

>>> print(pretty(expr, use_unicode=False))
/
|
|     ___
|    / 1
|   /  -  dx
| \/   x
|
/

:func:~diofant.printing.pretty.pretty.pprint prints the output to the screen.

>>> pprint(expr)
⌠
⎮     ___
⎮    ╱ 1
⎮   ╱  ─  dx
⎮ ╲╱   x
⌡

## LaTeX

To get the LaTeX form of an expression, use :func:~diofant.printing.latex.latex.

>>> print(latex(expr))
\int \sqrt{\frac{1}{x}}\, dx

## Dot

:func:~diofant.printing.dot.dotprint function prints output to dot format, which can be rendered with Graphviz:

.. graphviz::

digraph{

# Graph style
"bgcolor"="transparent"
"ordering"="out"
"rankdir"="TD"

#########
# Nodes #
#########

"Integral(Pow(Pow(Symbol('x'), Integer(-1)), Rational(1, 2)), Tuple(Symbol('x')))_()" ["color"="black", "label"="Integral", "shape"="ellipse"];
"Pow(Pow(Symbol('x'), Integer(-1)), Rational(1, 2))_(0,)" ["color"="black", "label"="Pow", "shape"="ellipse"];
"Pow(Symbol('x'), Integer(-1))_(0, 0)" ["color"="black", "label"="Pow", "shape"="ellipse"];
"Symbol('x')_(0, 0, 0)" ["color"="black", "label"="x", "shape"="ellipse"];
"Integer(-1)_(0, 0, 1)" ["color"="black", "label"="-1", "shape"="ellipse"];
"Rational(1, 2)_(0, 1)" ["color"="black", "label"="1/2", "shape"="ellipse"];
"Tuple(Symbol('x'))_(1,)" ["color"="blue", "label"="Tuple", "shape"="ellipse"];
"Symbol('x')_(1, 0)" ["color"="black", "label"="x", "shape"="ellipse"];

#########
# Edges #
#########

"Integral(Pow(Pow(Symbol('x'), Integer(-1)), Rational(1, 2)), Tuple(Symbol('x')))_()" -> "Pow(Pow(Symbol('x'), Integer(-1)), Rational(1, 2))_(0,)";
"Integral(Pow(Pow(Symbol('x'), Integer(-1)), Rational(1, 2)), Tuple(Symbol('x')))_()" -> "Tuple(Symbol('x'))_(1,)";
"Pow(Pow(Symbol('x'), Integer(-1)), Rational(1, 2))_(0,)" -> "Pow(Symbol('x'), Integer(-1))_(0, 0)";
"Pow(Pow(Symbol('x'), Integer(-1)), Rational(1, 2))_(0,)" -> "Rational(1, 2)_(0, 1)";
"Pow(Symbol('x'), Integer(-1))_(0, 0)" -> "Symbol('x')_(0, 0, 0)";
"Pow(Symbol('x'), Integer(-1))_(0, 0)" -> "Integer(-1)_(0, 0, 1)";
"Tuple(Symbol('x'))_(1,)" -> "Symbol('x')_(1, 0)";
}