added readme and license files

LICENSE

+Copyright (c) 2009 , UT-Battelle, LLC
+All rights reserved
+
+[PsimagLite, Version 1.0.0]
+[by G.A., Oak Ridge National Laboratory]
+
+UT Battelle Open Source Software License 11242008
+
+OPEN SOURCE LICENSE
+
+Subject to the conditions of this License, each
+contributor to this software hereby grants, free of
+charge, to any person obtaining a copy of this software
+and associated documentation files (the "Software"), a
+perpetual, worldwide, non-exclusive, no-charge,
+royalty-free, irrevocable copyright license to use, copy,
+modify, merge, publish, distribute, and/or sublicense
+copies of the Software.
+
+1. Redistributions of Software must retain the above
+copyright and license notices, this list of conditions,
+and the following disclaimer.  Changes or modifications
+to, or derivative works of, the Software should be noted
+with comments and the contributor and organization's
+name.
+
+2. Neither the names of UT-Battelle, LLC or the
+Department of Energy nor the names of the Software
+contributors may be used to endorse or promote products
+derived from this software without specific prior written
+permission of UT-Battelle.
+
+3. The software and the end-user documentation included
+with the redistribution, with or without modification,
+must include the following acknowledgment:
+
+"This product includes software produced by UT-Battelle,
+LLC under Contract No. DE-AC05-00OR22725  with the
+Department of Energy."
+ 
+*********************************************************
+DISCLAIMER
+
+THE SOFTWARE IS SUPPLIED BY THE COPYRIGHT HOLDERS AND
+CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
+WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+COPYRIGHT OWNER, CONTRIBUTORS, UNITED STATES GOVERNMENT,
+OR THE UNITED STATES DEPARTMENT OF ENERGY BE LIABLE FOR
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
+DAMAGE.
+
+NEITHER THE UNITED STATES GOVERNMENT, NOR THE UNITED
+STATES DEPARTMENT OF ENERGY, NOR THE COPYRIGHT OWNER, NOR
+ANY OF THEIR EMPLOYEES, REPRESENTS THAT THE USE OF ANY
+INFORMATION, DATA, APPARATUS, PRODUCT, OR PROCESS
+DISCLOSED WOULD NOT INFRINGE PRIVATELY OWNED RIGHTS.
+
+*********************************************************
+
+

README

+PsimagLite contains utilities for use in codes for the simulation of strongly correlated electrons.
+It is inspired in T.S.'s Psimag software (but it is not a fork of Psimag).
+The amount of functionality included in PsimagLite will be exactly this (subject to change):
+
+ModuleName	Description
+[Misc]	PSIMAGAssert.h
+[LinearAlgebra]	Includes BLAS/LAPACK wrappers, Matrix.h and a new Vector.h class.
+[Json] 	Json support (taken from M.S.'s new implementation which doesn't depend on anything at all)
+[Xml] 	Xml support (M.S.'s Tag*.h files) I will include but not maintain this.
+[Io]	Brandnew and fresh input output support
+[Concurrency]	Concurrency classes taken from DCA++ (gbranch)
+[SystemInfo]	Basic time/date capability, os, hostname, compiler info
+[Profiling]	Profiling through constructor/destructor paradigm as done by M.S in DCA++
+[RandomNumberGenerator]	Will include a good rng and a bad one/easy one for testing
+[Interpolation] Akima splines
+
+The reason for PsimagLite is to share code among SpinPhononFermion, DCA++ and DMRG++. 
+
+PsimagLite is free software (see file LICENSE) 
+
+PsimagLite and DMRG++
+Users will notice no change. Developers should not change DMRG++'s PSimagLite but do development on PsimagLite's separate repo instead. The fact that PsimagLite is in DMRG++'s repo is simply a convenience for users.
+In the future, users might need to download PsimagLite to be able to compile DMRG++. I will post a notice if this becomes true.
+
+PsimagLite and SpinPhononFermion
+Same as DMRG++ above. 
+

src/Akima.h

@@ -2,17 +2,24 @@
 #define AKIMA_H_
 
 //! A class to interpolate using akima spline
+template<typename VectorType>
 class Akima {
+	typedef typename VectorType::ValueType RealType;
+	
 	struct AkimaStruct {
 		RealType x0,x1,a0,a1,a2,a3;
 	};
-
+	
+	
 	public:
 		Akima(const VectorType& x,const VectorType& s)
 		{
+			if (x.size()!=s.size())
+				throw std::runtime_error("Number of X and Y points must be the same\n");
+
 			std::vector<RealType> sprime;
 			calculateSprime(sprime,x,s);
-			for (size_t i=0;i<n;i++) {
+			for (size_t i=0;i<x.size();i++) {
 				RealType u = x[i+1]-x[i];
 				RealType a2 = u*(sprime[i+1]-sprime[i])-2*(s[i+1]-s[i]));
 				RealType a3 = 3*u*(s[i+1]-s[i])-u*u*(sprime[i+1]+2*sprime[i]);
@@ -52,6 +59,27 @@ class Akima {
 			return i;
 		}
 		
+		void calculateSprime(VectorType& sprime,const VectorType& x,const VectorType& s)
+		{
+			VectorType d,w;
+			calculateD(d,x,s);
+			for (size_t i=0;i<x.size();i++) {
+				if (cornerCase()) {
+					// do corner case
+					continue;
+				}
+				sprime[i] = w[i]*d[i]+w[i+1]*d[i+1];
+				sprime[i] /= (w[i]+w[i+1]);
+			}
+		}
+		
+		void calculateD(VectorType& d,const VectorType& x,const VectorType& s)
+		{
+			for (size_t i=2;i<x.size();i++) 
+				d[i] = (s[i+1]-s[i])/(x[i+1]-x[i]);
+			
+		}
+		
 		std::vector<AkimaStruct> akimaStruct_;
 };