From: Michael Orlitzky <michael@orlitzky.com>
Date: Thu, 20 Dec 2018 02:58:19 +0000 (-0500)
Subject: Revert "... add completely_positive_operators_gens()."
X-Git-Url: https://gitweb.michael.orlitzky.com/?a=commitdiff_plain;h=cd27379ca353c51621a61af17411585d2542f6e5;p=sage.d.git

Revert "... add completely_positive_operators_gens()."

This reverts commit 3d6ec3f4f138a6278be4f393b491aa1ac2bbffa8. The new
function was mathematically wrong, and can't be fixed. Oops.
---

diff --git a/mjo/cone/completely_positive.py b/mjo/cone/completely_positive.py
index 15be558..8638a63 100644
--- a/mjo/cone/completely_positive.py
+++ b/mjo/cone/completely_positive.py
@@ -195,57 +195,3 @@ def is_extreme_completely_positive(A):
     # factorization into `$XX^{T}$` may not be unique!
     raise ValueError('Unable to determine extremity of ``A``.')
 
-
-
-def completely_positive_operators_gens(K):
-    r"""
-    Return a list of generators (matrices) for the completely-positive
-    cone of ``K``.
-
-    INPUT:
-
-    - ``K`` -- a closed convex rational polyhedral cone.
-
-    OUTPUT:
-
-    A list of matrices, the conic hull of which is the
-    completely-positive cone of ``K``.
-
-    SETUP::
-
-        sage: from mjo.cone.completely_positive import (
-        ....:   completely_positive_operators_gens,
-        ....:   is_completely_positive )
-        sage: from mjo.cone.nonnegative_orthant import nonnegative_orthant
-        sage: from mjo.matrix_vector import isomorphism
-
-    EXAMPLES::
-
-        sage: K = nonnegative_orthant(2)
-        sage: completely_positive_operators_gens(K)
-        [
-        [1 0]  [0 0]
-        [0 0], [0 1]
-        ]
-        sage: all( is_completely_positive(M)
-        ....:      for M in completely_positive_operators_gens(K) )
-        True
-
-    TESTS:
-
-    The completely-positive cone of ``K`` is subdual::
-
-       sage: K = random_cone(max_ambient_dim=8, max_rays=10)
-       sage: cp_gens = completely_positive_operators_gens(K)
-       sage: n = K.lattice_dim()
-       sage: M = MatrixSpace(QQ, n, n)
-       sage: (p, p_inv) = isomorphism(M)
-       sage: L = ToricLattice(n**2)
-       sage: cp_cone = Cone( (p(m) for m in cp_gens), lattice=L )
-       sage: copos_cone = Cone(cp_cone.dual().rays(), lattice=L )
-       sage: all( x in copos_cone for x in cp_cone )
-       True
-
-    """
-    return [ x.tensor_product(x) for x in K ]
-