Composed function - segmetnation violation

I am trying to build and draw a composed function with a very simple code, but when I run the macro i obtain a segmentation violation error which I cannot understand. I don’t know if I am doing something
wrong but I cannot see it.
This is my code:

double FD(double *x, double *p){
    double t0, A,B,C;
    t0=p[0];
    A=p[1];
    B=p[2];

    double result = A/( 1+exp( -(x[0]-t0)/B ) );
    return result;
}

double FDL(double *x, double *p){
        double t, t0, A,B,C, sigma;
        t0   = p[0];
        A    = p[1];
        B    = p[2];
        sigma= p[3];
        t    = x[0];
        double result;    
        double *FDpars;
        double *FDx;
        //TF1 *F = new TF1("fermidirac",FD,0,512,3);
        if(t<t0){
            FDpars[0]=t0,
            FDpars[1]=A;
            FDpars[2]=B;
            FDx[0]=t0;
            result=FD(FDx,FDpars);
        }else if(t>t0){
            result=TMath::Landau(t,t0,sigma);
        }

        return result;
}


void DrawFDL(){
    TF1 *fermidiraclandau = new TF1("fdl",FDL,0,512,4);
    fermidiraclandau->SetParameter(0,330);
    fermidiraclandau->SetParameter(1,1);
    fermidiraclandau->SetParameter(2,1);
    fermidiraclandau->SetParameter(3,1);
    fermidiraclandau->Draw();
    return;
}
        double FDpars[3];
        double FDx[1];

That actually worked. Thanks