From 055de2c798d2ff229a7ddfed5de03a2d32b8fea5 Mon Sep 17 00:00:00 2001
From: knodlseder <>
Date: Wed, 3 Aug 2011 06:32:07 +0000
Subject: [PATCH] move here from test directory

---
 examples/pull_histogram.py | 125 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 125 insertions(+), 0 deletions(-)
 create mode 100755 examples/pull_histogram.py

diff --git a/examples/pull_histogram.py b/examples/pull_histogram.py
new file mode 100755
index 0000000..27b8868
--- /dev/null
+++ b/examples/pull_histogram.py
@@ -0,0 +1,125 @@
+#! /usr/bin/env python
+# ==========================================================================
+# This script displays pull histograms that have been generated using the
+# cspull script. The pull is defined by
+#
+#           (fitted value - simulated value) / estimated error
+#
+# and the pull histogram allows to assess possible biases in the fit
+# parameters and errors.
+#
+# Requirements:
+# - matplotlib
+# - numpy
+#
+# Copyright (C) 2011 Jurgen Knodlseder
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+# ==========================================================================
+import matplotlib.mlab as mlab
+import matplotlib.pyplot as plt
+import numpy as np
+import sys
+import csv
+
+
+# ====================== #
+# Read pull distribution #
+# ====================== #
+def read_pull(filename, parname):
+	"""
+	Read pull distribution.
+	"""
+	# Initialise list
+	values = []
+	
+	# Open reader
+	reader = csv.reader(open(filename, 'r'), delimiter=',')
+	
+	# Read rows
+	first = True
+	index = -1
+	for row in reader:
+		
+		# Get column index if first row
+		if first:
+			try:
+				index = row.index(parname)
+			except:
+				print 'ERROR: Parameter "'+parname+'" not found in list:'
+				for p in row:
+					print '       "'+p+'"'
+				raise NameError(parname)
+			#print index
+
+		# Handle data rows
+		else:
+			values.append(float(row[index]))
+		
+		# Flag that first row has been passed
+		first = False
+	
+	# Create numpy array
+	a = np.array(values)
+	#print a
+	
+	# Return array
+	return a
+
+
+# ======================== #
+# Main routine entry point #
+# ======================== #
+if __name__ == '__main__':
+	"""
+	Display pull histogram generated by cspull using matplotlib.
+	"""
+	# Print usage information
+	usage = "Usage: pull_histogram filename parname [bins]"
+	if len(sys.argv) < 3:
+		print usage
+		sys.exit()
+
+	# Extract parameters
+	filename = sys.argv[1]
+	parname  = sys.argv[2]
+	if len(sys.argv) > 3:
+		nbins = int(sys.argv[3])
+	else:
+		nbins = 50
+	
+	# Read values from CSV file
+	values = read_pull(filename, parname)
+	
+	# Create histogram
+	n, bins, patches = plt.hist(values, nbins, range=[-4.0,4.0],
+								normed=True, facecolor='green')
+
+	# Create expected distribution
+	y = mlab.normpdf(bins, 0.0, 1.0)
+	l = plt.plot(bins, y, 'r-', linewidth=2)
+
+	# Set parname for plotting
+	name = parname
+	
+	# Set plot
+	plt.xlabel('Pull ('+name+')')
+	plt.ylabel('Arbitrary units')
+	plt.title(name)
+	plt.grid(True)
+
+	# Show histogram
+	plt.show()
+	
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