def addlp(M, M1, L, P, ptsdict, G=None, limits=None):
"""
Return a graphics object containing loops (in inset) and parallel elements
of matroid.
INPUT:
- ``M`` -- A matroid.
- ``M1`` -- A simple matroid corresponding to ``M``.
- ``L`` -- List of elements in ``M.groundset()`` that are loops of matroid
``M``.
- ``P`` -- List of elements in ``M.groundset()`` not in
``M.simplify.groundset()`` or ``L``.
- ``ptsdict`` -- A dictionary containing elements in ``M.groundset()`` not
necessarily containing elements of ``L``.
- ``G`` -- (optional) A sage graphics object to which loops and parallel
elements of matroid `M` added .
- ``limits``-- (optional) Current axes limits [xmin,xmax,ymin,ymax].
OUTPUT:
A 2-tuple containing:
1. A sage graphics object containing loops and parallel elements of
matroid ``M``
2. axes limits array
EXAMPLES::
sage: from sage.matroids import matroids_plot_helpers
sage: M=Matroid(ring=GF(2), matrix=[[1, 0, 0, 0, 1, 1, 1,0,1],
....: [0, 1, 0, 1, 0, 1, 1,0,0],[0, 0, 1, 1, 1, 0, 1,0,0]])
sage: [M1,L,P]=matroids_plot_helpers.slp(M)
sage: G,lims=matroids_plot_helpers.addlp(M,M1,L,P,{0:(0,0)})
sage: G.show(axes=False)
.. NOTE::
This method does NOT do any checks.
"""
if G is None:
G = Graphics()
# deal with loops
if len(L) > 0:
loops = L
looptext = ", ".join([str(l) for l in loops])
if(limits is None):
rectx = -1
recty = -1
else:
rectx = limits[0]
recty = limits[2]-1
rectw = 0.5 + 0.4*len(loops) + 0.5 # controlled based on len(loops)
recth = 0.6
G += polygon2d([[rectx, recty], [rectx, recty+recth],
[rectx+rectw, recty+recth], [rectx+rectw, recty]],
color='black', fill=False, thickness=4)
G += text(looptext, (rectx+0.5, recty+0.3), color='black',
fontsize=13)
G += point((rectx+0.2, recty+0.3), color=Color('#BDBDBD'), size=300,
zorder=2)
G += text('Loop(s)', (rectx+0.5+0.4*len(loops)+0.1, recty+0.3),
fontsize=13, color='black')
limits = tracklims(limits, [rectx, rectx+rectw], [recty, recty+recth])
# deal with parallel elements
if len(P) > 0:
# create list of lists where inner lists are parallel classes
pcls = []
gnd = sorted(list(M1.groundset()))
for g in gnd:
pcl = [g]
for p in P:
if M.rank([g, p]) == 1:
pcl.extend([p])
pcls.append(pcl)
ext_gnd = list(M.groundset())
for pcl in pcls:
if len(pcl) > 1:
basept = list(ptsdict[pcl[0]])
if len(pcl) <= 2:
# add side by side
ptsdict[pcl[1]] = (basept[0], basept[1]-0.13)
G += points(zip([basept[0]], [basept[1]-0.13]),
color=Color('#BDBDBD'), size=300, zorder=2)
G += text(pcl[0], (float(basept[0]),
float(basept[1])), color='black',
fontsize=13)
G += text(pcl[1], (float(basept[0]),
float(basept[1])-0.13), color='black',
fontsize=13)
limits = tracklims(limits, [basept[0]], [basept[1]-0.13])
else:
# add in a bracket
pce = sorted([str(kk) for kk in pcl])
l = newlabel(set(ext_gnd))
ext_gnd.append(l)
G += text(l+'={ '+", ".join(pce)+' }', (float(basept[0]),
float(basept[1]-0.2)-0.034), color='black',
fontsize=13)
G += text(l, (float(basept[0]),
float(basept[1])), color='black',
fontsize=13)
limits = tracklims(limits, [basept[0]],
[(basept[1]-0.2)-0.034])
return G, limits
def addlp(M, M1, L, P, ptsdict, G=None, limits=None):
"""
Return a graphics object containing loops (in inset) and parallel elements
of matroid.
INPUT:
- ``M`` -- A matroid.
- ``M1`` -- A simple matroid corresponding to ``M``.
- ``L`` -- List of elements in ``M.groundset()`` that are loops of matroid
``M``.
- ``P`` -- List of elements in ``M.groundset()`` not in
``M.simplify.groundset()`` or ``L``.
- ``ptsdict`` -- A dictionary containing elements in ``M.groundset()`` not
necessarily containing elements of ``L``.
- ``G`` -- (optional) A sage graphics object to which loops and parallel
elements of matroid `M` added .
- ``limits``-- (optional) Current axes limits [xmin,xmax,ymin,ymax].
OUTPUT:
A 2-tuple containing:
1. A sage graphics object containing loops and parallel elements of
matroid ``M``
2. axes limits array
EXAMPLES::
sage: from sage.matroids import matroids_plot_helpers
sage: M=Matroid(ring=GF(2), matrix=[[1, 0, 0, 0, 1, 1, 1,0,1],
....: [0, 1, 0, 1, 0, 1, 1,0,0],[0, 0, 1, 1, 1, 0, 1,0,0]])
sage: [M1,L,P]=matroids_plot_helpers.slp(M)
sage: G,lims=matroids_plot_helpers.addlp(M,M1,L,P,{0:(0,0)})
sage: G.show(axes=False)
.. NOTE::
This method does NOT do any checks.
"""
if G is None:
G = Graphics()
# deal with loops
if len(L) > 0:
loops = L
looptext = ", ".join([str(l) for l in loops])
if (limits is None):
rectx = -1
recty = -1
else:
rectx = limits[0]
recty = limits[2] - 1
rectw = 0.5 + 0.4 * len(loops) + 0.5 # controlled based on len(loops)
recth = 0.6
G += polygon2d(
[[rectx, recty], [rectx, recty + recth],
[rectx + rectw, recty + recth], [rectx + rectw, recty]],
color='black',
fill=False,
thickness=4)
G += text(looptext, (rectx + 0.5, recty + 0.3),
color='black',
fontsize=13)
G += point((rectx + 0.2, recty + 0.3),
color=Color('#BDBDBD'),
size=300,
zorder=2)
G += text('Loop(s)',
(rectx + 0.5 + 0.4 * len(loops) + 0.1, recty + 0.3),
fontsize=13,
color='black')
limits = tracklims(limits, [rectx, rectx + rectw],
[recty, recty + recth])
# deal with parallel elements
if len(P) > 0:
# create list of lists where inner lists are parallel classes
pcls = []
gnd = sorted(list(M1.groundset()))
for g in gnd:
pcl = [g]
for p in P:
if M.rank([g, p]) == 1:
pcl.extend([p])
pcls.append(pcl)
ext_gnd = list(M.groundset())
for pcl in pcls:
if len(pcl) > 1:
basept = list(ptsdict[pcl[0]])
if len(pcl) <= 2:
# add side by side
ptsdict[pcl[1]] = (basept[0], basept[1] - 0.13)
G += points(zip([basept[0]], [basept[1] - 0.13]),
color=Color('#BDBDBD'),
size=300,
zorder=2)
G += text(pcl[0], (float(basept[0]), float(basept[1])),
color='black',
fontsize=13)
G += text(pcl[1],
(float(basept[0]), float(basept[1]) - 0.13),
color='black',
fontsize=13)
limits = tracklims(limits, [basept[0]], [basept[1] - 0.13])
else:
# add in a bracket
pce = sorted([str(kk) for kk in pcl])
l = newlabel(set(ext_gnd))
ext_gnd.append(l)
G += text(
l + '={ ' + ", ".join(pce) + ' }',
(float(basept[0]), float(basept[1] - 0.2) - 0.034),
color='black',
fontsize=13)
G += text(l, (float(basept[0]), float(basept[1])),
color='black',
fontsize=13)
limits = tracklims(limits, [basept[0]],
[(basept[1] - 0.2) - 0.034])
return G, limits