Procedure SVDFIT(X,Y,SIG:array of real; NDATA:integer;var A:array of real;
                               MA:integer;var U, V:matrx2;var W:array of real;
                                     MP, NP:integer;var CHISQ:real; FUNCS:string);
var
    B:array[0..1000] of real; AFUNC:array[0..50] of real;
    I,J:integer;   TMP,WMAX,THRESH,SUM1:real;
const
    TOL=0.00001;
begin
    For I:=1 To NDATA do
    begin
        If FUNCS = 'FPOLY' Then FPOLY(X[I], AFUNC, MA);
        If FUNCS = 'FLEG'  Then FLEG(X[I], AFUNC, MA);
        TMP:=1 / SIG[I];
        For J:=1 To MA do
            U[I, J]:=AFUNC[J] * TMP;
        B[I]:=Y[I] * TMP;
    end; 
    SVDCMP(U, NDATA, MA, W, V);
    WMAX:=0; 
    For J:=1 To MA do
        If W[J] > WMAX Then WMAX:=W[J];
    THRESH:=TOL * WMAX;
    For J:=1 To MA do
        If W[J] < THRESH Then W[J]:=0; 
    SVBKSB(U, W, V, NDATA, MA, B, A);
    CHISQ:=0; 
    For I:=1 To NDATA do
    begin
        If FUNCS = 'FPOLY' Then FPOLY(X[I], AFUNC, MA);
        If FUNCS = 'FLEG' Then FLEG(X[I], AFUNC, MA);
        SUM1:=0; 
        For J:= 1 To MA do
            SUM1:=SUM1 + A[J] * AFUNC[J];
        CHISQ:=CHISQ + Sqr((Y[I] - SUM1) / SIG[I]);
    end; 
end;