DOC: Update poly class refguide printing.

Update routines.polynomials.classes doc in the refguide to reflect
changes to polynomial printing.

Add additional information to the document about the various ways that
the string representation of polynomial expressions can be controlled
via formatting.

2 files changed, 26 insertions, 3 deletions

diff --git a/doc/source/reference/routines.polynomials.classes.rst b/doc/source/reference/routines.polynomials.classes.rst
index 71e635866..10331e9c1 100644
--- a/doc/source/reference/routines.polynomials.classes.rst
+++ b/doc/source/reference/routines.polynomials.classes.rst
@@ -65,11 +65,26 @@ window::
    >>> p.window
    array([-1.,  1.])
 
-Printing a polynomial yields a shorter form without the domain
-and window::
+Printing a polynomial yields the polynomial expression in a more familiar
+format::
 
    >>> print(p)
-   poly([1. 2. 3.])
+   1.0 + 2.0·x¹ + 3.0·x²
+
+Note that the string representation of polynomials uses Unicode characters
+by default (except on Windows) to express powers and subscripts. An ASCII-based
+representation is also available (default on Windows). The polynomial string
+format can be toggled at the package-level with the 
+`~numpy.polynomial.set_default_printstyle` function::
+
+   >>> numpy.polynomial.set_default_printstyle('ascii')
+   >>> print(p)
+   1.0 + 2.0 x**1 + 3.0 x**2
+
+or controlled for individual polynomial instances with string formatting::
+
+   >>> print(f"{p:unicode}")
+   1.0 + 2.0·x¹ + 3.0·x²
 
 We will deal with the domain and window when we get to fitting, for the moment
 we ignore them and run through the basic algebraic and arithmetic operations.
diff --git a/doc/source/reference/routines.polynomials.package.rst b/doc/source/reference/routines.polynomials.package.rst
index ca1217f80..1bc528c59 100644
--- a/doc/source/reference/routines.polynomials.package.rst
+++ b/doc/source/reference/routines.polynomials.package.rst
@@ -4,3 +4,11 @@
    :no-members:
    :no-inherited-members:
    :no-special-members:
+
+Configuration
+-------------
+
+.. autosummary:: 
+   :toctree: generated/
+
+   numpy.polynomial.set_default_printstyle