function m=ahpmakemat(a)
%AHPMAKEMAT    Turn a vector of comparisons into an AHP matrix.
%   M=AHPMAKEMAT(A) returns an AHP matrix M from an input vector A.
%   A must be a triangular number to correctly populate M.
%   The entries of A appear in M as follows:
%
%             M=[1  A(1)  A(2)  ...   A(Q)
%                    1   A(Q+1) ...
%                             ...       
%                                  1  A(N)  
%                                      1  ]
sz=size(a);
numrows=sz(1);
if (numrows > 1)
 a = a';
 sz=size(a);
 numrows=sz(1);
end
if (numrows >1)
 disp('Sorry, this only works for vectors right now.')
 disp('Exiting.');
 return;
end
numcols=sz(2);
n=0.5*(1+sqrt(1+8*numcols));
if (n-round(n) ~= 0)
 disp('The input array must have a column count that is a triangular number.');
 disp('Exiting.');
 return;
end
m=eye(n);
vecindex=1;
for i=1:(n-1)
 for j=(i+1):n
  m(i,j)=a(vecindex);
  vecindex=vecindex+1;
  m(j,i)=1/m(i,j);
 end
end