function [ PHISOL ] = calculgram(Nbtermes,NPT,T,dt,z0M,dz0M,alpha0M,dalpha0M,Rad,B0,C0,F0,a0,b0)
%==================
% construction de la matrice de Gram
%==================
GRAMM=zeros(4,4);
%==================
phi0=0.*linspace(1,4,4);
deltaphi0=0.*linspace(1,4,4);
Lsec=linspace(1,2,4)*0.;
     P1dot=linspace(1,2,NPT);
     P2dot=linspace(1,2,NPT);
     Q1dot=linspace(1,2,NPT);
     Q2dot=linspace(1,2,NPT);
%=================
for k1=1:4
  for i1=1:4
        if(i1 == k1)
                phi0(i1)=1;
        else
                phi0(i1)=0;
        end
  end
    [P1,P2]=soluedo(Rad,NPT,dt,phi0);
     P1dot(1)=phi0(2);
     P2dot(1)=phi0(4);
    
     for i=2:NPT
         P1dot(i)=(P1(i)-P1(i-1))/dt;
         P2dot(i)=(P2(i)-P2(i-1))/dt;
     end
     Lsec(k1)=dz0M*phi0(1)+dalpha0M*phi0(3)-z0M*phi0(2)-alpha0M*phi0(4);
     squatro=0;
     for jkl=1:NPT
         squatro=squatro+F0(1)*P1(jkl)+F0(2)*P2(jkl);
     end
     Lsec(k1)=Lsec(k1)+squatro*dt;
  %==============
  for k2=k1:4
       for i2=1:4
          if(i2 == k2)
               deltaphi0(i2)=1;
          else
               deltaphi0(i2)=0;
          end
        end
%==================
% Remplissage des solution elementaire
%==================
    [Q1,Q2]=soluedo(Rad,NPT,dt,deltaphi0);
     Q1dot(1)=deltaphi0(2);
     Q2dot(1)=deltaphi0(4);
     for i=2:NPT   
      Q1dot(i)=(Q1(i)-Q1(i-1))/dt;
      Q2dot(i)=(Q2(i)-Q2(i-1))/dt;
     end
%========   
% calcul des termes de GRAMM(Monsieur Gram)
%========
  
    for n=1:Nbtermes
        coef=dt^2/(a0+b0*n^2*pi^2/T^2);
        sbis=0;
        ster=0;
        %
        for jj=1:NPT
        sinusnjj=sin(n*pi*jj*dt/T);
        sbis=sbis+sinusnjj*(C0(1)*P1dot(jj)+C0(2)*P2dot(jj)-B0(1)*P1(jj)-B0(2)*P2(jj));
        ster=ster+sinusnjj*(C0(1)*Q1dot(jj)+C0(2)*Q2dot(jj)-B0(1)*Q1(jj)-B0(2)*Q2(jj));
        end
        
  
    GRAMM(k1,k2)=GRAMM(k1,k2)+sbis*ster*coef;
    GRAMM(k2,k1)=GRAMM(k1,k2);
    end
 end
end
GRAMM=(2/T)*GRAMM
%======
%  calcul de PHI
%======
PHISOL=linsolve(GRAMM,Lsec');


end