You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: spm_inv_spd.m
    path of file: ./repos/bspm/thirdparty/spm12
    
    the code of the file until where you have to start completion: function X = spm_inv_spd(A, TOL)
% Inverse for symmetric positive (semi)definite matrices

    
function X = spm_inv_spd(A, TOL)
% Inverse for symmetric positive (semi)definite matrices
% FORMAT X = spm_inv_spd(A,TOL)
%
% A   - symmetric positive definite matrix (e.g. covariance or precision)
% X   - inverse (should remain symmetric positive definite)
%
% TOL - tolerance: default = exp(-32)
%__________________________________________________________________________
% Copyright (C) 2011 Wellcome Trust Centre for Neuroimaging
 
% Ged Ridgway
% $Id: spm_inv_spd.m 5219 2013-01-29 17:07:07Z spm $

% if ~all(isfinite(A(:))), error('Matrix has non-finite elements!'); end