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#!/usr/bin/env python
__author__ = "Yannick Copin <ycopin@ipnl.in2p3.fr>"
__version__ = "Time-stamp: <10/02/2010 16:49 ycopin@lyopc548.in2p3.fr>"
import numpy as N
def sankey(ax,
outputs=[100.], outlabels=None,
inputs=[100.], inlabels='',
dx=40, dy=10, outangle=45, w=3, inangle=30, offset=2, **kwargs):
"""Draw a Sankey diagram.
outputs: array of outputs, should sum up to 100%
outlabels: output labels (same length as outputs),
or None (use default labels) or '' (no labels)
inputs and inlabels: similar for inputs
dx: horizontal elongation
dy: vertical elongation
outangle: output arrow angle [deg]
w: output arrow shoulder
inangle: input dip angle
offset: text offset
**kwargs: propagated to Patch (e.g. fill=False)
Return (patch,[intexts,outtexts])."""
import matplotlib.patches as mpatches
from matplotlib.path import Path
outs = N.absolute(outputs)
outsigns = N.sign(outputs)
outsigns[-1] = 0 # Last output
ins = N.absolute(inputs)
insigns = N.sign(inputs)
insigns[0] = 0 # First input
assert sum(outs)==100, "Outputs don't sum up to 100%"
assert sum(ins)==100, "Inputs don't sum up to 100%"
def add_output(path, loss, sign=1):
h = (loss/2+w)*N.tan(outangle/180.*N.pi) # Arrow tip height
move,(x,y) = path[-1] # Use last point as reference
if sign==0: # Final loss (horizontal)
path.extend([(Path.LINETO,[x+dx,y]),
(Path.LINETO,[x+dx,y+w]),
(Path.LINETO,[x+dx+h,y-loss/2]), # Tip
(Path.LINETO,[x+dx,y-loss-w]),
(Path.LINETO,[x+dx,y-loss])])
outtips.append((sign,path[-3][1]))
else: # Intermediate loss (vertical)
path.extend([(Path.CURVE4,[x+dx/2,y]),
(Path.CURVE4,[x+dx,y]),
(Path.CURVE4,[x+dx,y+sign*dy]),
(Path.LINETO,[x+dx-w,y+sign*dy]),
(Path.LINETO,[x+dx+loss/2,y+sign*(dy+h)]), # Tip
(Path.LINETO,[x+dx+loss+w,y+sign*dy]),
(Path.LINETO,[x+dx+loss,y+sign*dy]),
(Path.CURVE3,[x+dx+loss,y-sign*loss]),
(Path.CURVE3,[x+dx/2+loss,y-sign*loss])])
outtips.append((sign,path[-5][1]))
def add_input(path, gain, sign=1):
h = (gain/2)*N.tan(inangle/180.*N.pi) # Dip depth
move,(x,y) = path[-1] # Use last point as reference
if sign==0: # First gain (horizontal)
path.extend([(Path.LINETO,[x-dx,y]),
(Path.LINETO,[x-dx+h,y+gain/2]), # Dip
(Path.LINETO,[x-dx,y+gain])])
xd,yd = path[-2][1] # Dip position
indips.append((sign,[xd-h,yd]))
else: # Intermediate gain (vertical)
path.extend([(Path.CURVE4,[x-dx/2,y]),
(Path.CURVE4,[x-dx,y]),
(Path.CURVE4,[x-dx,y+sign*dy]),
(Path.LINETO,[x-dx-gain/2,y+sign*(dy-h)]), # Dip
(Path.LINETO,[x-dx-gain,y+sign*dy]),
(Path.CURVE3,[x-dx-gain,y-sign*gain]),
(Path.CURVE3,[x-dx/2-gain,y-sign*gain])])
xd,yd = path[-4][1] # Dip position
indips.append((sign,[xd,yd+sign*h]))
outtips = [] # Output arrow tip dir. and positions
urpath = [(Path.MOVETO,[0,100])] # 1st point of upper right path
lrpath = [(Path.LINETO,[0,0])] # 1st point of lower right path
for loss,sign in zip(outs,outsigns):
add_output(sign>=0 and urpath or lrpath, loss, sign=sign)
indips = [] # Input arrow tip dir. and positions
llpath = [(Path.LINETO,[0,0])] # 1st point of lower left path
ulpath = [(Path.MOVETO,[0,100])] # 1st point of upper left path
for gain,sign in zip(ins,insigns)[::-1]:
add_input(sign<=0 and llpath or ulpath, gain, sign=sign)
def revert(path):
"""A path is not just revertable by path[::-1] because of Bezier
curves."""
rpath = []
nextmove = Path.LINETO
for move,pos in path[::-1]:
rpath.append((nextmove,pos))
nextmove = move
return rpath
# Concatenate subpathes in correct order
path = urpath + revert(lrpath) + llpath + revert(ulpath)
codes,verts = zip(*path)
verts = N.array(verts)
# Path patch
path = Path(verts,codes)
patch = mpatches.PathPatch(path, **kwargs)
ax.add_patch(patch)
if False: # DEBUG
print "urpath", urpath
print "lrpath", revert(lrpath)
print "llpath", llpath
print "ulpath", revert(ulpath)
xs,ys = zip(*verts)
ax.plot(xs,ys,'go-')
# Labels
def set_labels(labels,values):
"""Set or check labels according to values."""
if labels=='': # No labels
return labels
elif labels is None: # Default labels
return [ '%2d%%' % val for val in values ]
else:
assert len(labels)==len(values)
return labels
def put_labels(labels,positions,output=True):
"""Put labels to positions."""
texts = []
lbls = output and labels or labels[::-1]
for i,label in enumerate(lbls):
s,(x,y) = positions[i] # Label direction and position
if s==0:
t = ax.text(x+offset,y,label,
ha=output and 'left' or 'right', va='center')
elif s>0:
t = ax.text(x,y+offset,label, ha='center', va='bottom')
else:
t = ax.text(x,y-offset,label, ha='center', va='top')
texts.append(t)
return texts
outlabels = set_labels(outlabels, outs)
outtexts = put_labels(outlabels, outtips, output=True)
inlabels = set_labels(inlabels, ins)
intexts = put_labels(inlabels, indips, output=False)
# Axes management
ax.set_xlim(verts[:,0].min()-dx, verts[:,0].max()+dx)
ax.set_ylim(verts[:,1].min()-dy, verts[:,1].max()+dy)
ax.set_aspect('equal', adjustable='datalim')
return patch,[intexts,outtexts]
if __name__=='__main__':
import matplotlib.pyplot as P
outputs = [10.,-20.,5.,15.,-10.,40.]
outlabels = ['First','Second','Third','Fourth','Fifth','Hurray!']
outlabels = [ s+'\n%d%%' % abs(l) for l,s in zip(outputs,outlabels) ]
inputs = [60.,-25.,15.]
fig = P.figure()
ax = fig.add_subplot(1,1,1, xticks=[],yticks=[],
title="Sankey diagram"
)
patch,(intexts,outtexts) = sankey(ax, outputs=outputs, outlabels=outlabels,
inputs=inputs, inlabels=None,
fc='g', alpha=0.2)
outtexts[1].set_color('r')
outtexts[-1].set_fontweight('bold')
P.show()
Keywords: python, matplotlib, pylab, example, codex (see Search examples)