From de08ab6ccbd541574291c52f2982a1322e0acbce Mon Sep 17 00:00:00 2001
From: apetri <apetri@phys.columbia.edu>
Date: Wed, 20 Apr 2016 15:18:53 -0400
Subject: [PATCH] added random and invert methods to Ensemble

---
 lenstools/statistics/ensemble.py | 36 ++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/lenstools/statistics/ensemble.py b/lenstools/statistics/ensemble.py
index e006495..b70f4c6 100644
--- a/lenstools/statistics/ensemble.py
+++ b/lenstools/statistics/ensemble.py
@@ -370,6 +370,28 @@ def save(self,filename,format=None,**kwargs):
 		else:
 			format(self,filename,**kwargs)
 
+	#############################################################
+	######Construct a random ensemble for testing purposes#######
+	#############################################################
+
+	@classmethod
+	def random(cls,nobs=10,columns=list("abc")):
+
+		"""
+		Construct a random ensemble for testing purposes, sampling from a univariate normal distribution in each column
+
+		:param nobs: number of observations (rows)
+		:type nobs: int.
+
+		:param columns: columns of the ensemble
+		:type columns: list.
+
+		:rtype: :py:class:`Ensemble`
+
+		"""
+
+		return cls(np.random.randn(nobs,len(columns)),columns=columns)
+
 
 	#################################################
 	#############Construct from meshgrid#############
@@ -827,6 +849,20 @@ def shuffle(self,seed=None):
 
 	#####################################################################################################################
 
+	def invert(self):
+
+		"""
+		If the Ensemble is a square matrix, compute its inverse
+
+		:rtype: :py:class:`Ensemble`
+
+		"""
+
+		if self.shape[0]!=self.shape[1]:
+			raise ValueError("This is not a square matrix!")
+
+		return self.__class__(np.linalg.inv(self.values),index=self.index,columns=self.columns)
+
 	####################################
 	#############Visualization##########
 	####################################