#18805: Add didactical implementation of tableau cutting planes to
interactive_simplex_method
-------------------------------------+-------------------------------------
Reporter: mkoeppe | Owner:
Type: enhancement | Status: needs_work
Priority: major | Milestone: sage-6.8
Component: numerical | Resolution:
Keywords: | Merged in:
Authors: Peijun Xiao | Reviewers: Andrey Novoseltsev
Report Upstream: N/A | Work issues: doc format
Branch: | Commit:
u/pjxiao/add_didactical_implementation_of_tableau_cutting_planes_to_interactive_simplex_method|
54cc5d123338bed43b1c97930c15ed1b9407c218
Dependencies: #18742 | Stopgaps:
-------------------------------------+-------------------------------------
Changes (by novoselt):
* status: needs_review => needs_work
Comment:
The very first change with all the commits::
{{{
+def form_thin_long_triangle(k):
+ r"""
+
+ Generate a thin long triangle with vertices (0, 0), (1, 0), and (1/2,
k)
+ for some given integer K, and return the triangle in Ax<=b form.
+ This thin long triangle is an example of a system with large Chvatal
rank.
+
+ INPUT:
+ -``k``-- an integer indicating the y coordinate of the top vertex for
the triangle
+
+ OUTPUT:
+ -``A`` -- a two by two matrix
+ -``b`` -- a two-element vector
+
+ EXAMPLES::
+ sage: from sage.numerical.interactive_simplex_method \
+ ....: import form_thin_long_triangle
+ sage: A, b, = form_thin_long_triangle(4)
+ sage: A, b
+ (([-8, 1], [8, 1]), (0, 8))
+
+ """
+ A = ([Integer(-2 * k), Integer(1)], [Integer(2 * k), Integer(1)])
+ b = (Integer(0), Integer(2 * k))
+ type(b[0])
+ return A, b
}}}
- empty line in the beginning of the docstring
- no one-line description in the beginning
- math should be written as LaTeX
- INPUT/OUTPUT/EXAMPLES blocks lack empty lines
- I do not understand the documentation - what does it mean to generate a
triangle in the form Ax<=b?
- the output does not match the documentation, A is not a matrix and b is
not a vector
- there is no need in `Integer` conversion (and its import)
- `type(...)` does nothing useful
- why would a user need such a function??? If it is for internal use,
perhaps start with underscore.
--
Ticket URL: <http://trac.sagemath.org/ticket/18805#comment:8>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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