Made multiplication of coefficients by -1 when initialized by the user
since the convention currently used is the same of the article which differ
from ARMA convention in OpenTURNS
Renamed blockMatrix variable into coefficientsBlockMatrix to be more informal
Added a precompute method for the computation of covariance matrix and
completed the computation of autocovariance matrix.
Added method to compute W0 matrix used to determine the theoritical autocovariance
Added differents methods which help the visibility of the complete process
Filled computeVMatrix method
Filled the omega matrix
Added boolean attributs to check if the coherancy of computation.
Added time series attribut to help the computation by passing data between
functions
Fixed some minor bugs
Updated the factory due to the merge process
Added currentG_ attribut to easily build some matrices
Added an initialize method which allows to allocate memory for matrices with
respect to the current values of p, q and currentG_
Completed the computeVMatrix method
Renamed buildOmegaMatrix into computeOmegaMatrix
Changed the type of prod_V_Omega_Vtranspose from SquareMatrix to Matrix
Changed some method outputs from Matrix to void by using an internal attribut
Removed useless precompute and build methods in computeAutoCovarianceMatrix
Completed the computation of the final covariance matrix. Only the lower part
is filled.
Fixed some wrong comments and completed missing ones
Rewrote computeW0Matrix, computeCrossCovarianceMatrix, computeOmegaMatrix,
computeVMatrix and prod_Dtheta_TensorialCovariance_DthetaTranspose by changing
the indexation notation to better conform the reading of comments / articles
Added the computeCholeskyFactor method.
Added missing test in build method. The size of the time series should be greater than the parameters
Changed indices numerotation in computeAutoCovariance method in order to conform the scientific articles
Added the transformData method in ARMALikelihoodFactory class
Added internal choleskyFactor attribut
Changed the return value of some methods to void
Started the write of the triangular linear system solve using lapack/blas
Masked some methods which became private
Added ARMALikelihoodFactory keys in ResourceMap and updated the
ARMALikelihodFactory class by using these last ones
Updated defaultInitialize arguments method and check in build method
Updated some comments to be in accordance with articles
Made distinction for general case and case p = 0 and q = 0
Move methods around to improve readability, no code change
Transpose and rename coefficientsBlockMatrix_ matrix

Most matrix multiplications with phi and theta are matrices are :
  phi * B or B * phi^{T}
Since OpenTurns use a column storage, it is more efficient to compute
  M_{ij} = A_{ik} B_{kj}
         = (A^{T})_{ki} B_{kj}
This is why transposed matrices are stored, and coefficientsBlockMatrix_
is renamed into blockPhiTThetaTMatrix_.

For the same reason, switch some loops on rows and columns.

Fix several occurrences of (currentP_ - 1) which may cause trouble
when currentP_ is 0.
Added a particular case of compute covariance method for pure AR models. This
method enables to compute the covariance matrix using the white noise
covariance matrix of size p
Removed some useless boolean variables and added verbose accessors
Renamed the logLikelihhod function and completed the method. This enables to
compute the main factor of the likelihood function
Completed the ComputeObjectiveAndConstraint method by setting the constraints
on AR values, MA values and covariance matrix
Completed the build method by launching the cobyla algorithm
Made some cleaning and fixed some minor bugs
Added ARMALikelihood library tests