EXTERNAL

SUB mrqcof (x(), y(), sig(), ndata, a(), ma, lista(), mfit, alpha(,), beta(,), nalp, chisq, dum)

    DIM dyda(0)
    MAT redim dyda(ma)

    FOR j = 1 to mfit
        FOR k = 1 to j
            LET alpha(j, k) = 0
        NEXT k
        LET beta(j, 1) = 0
    NEXT j
    LET chisq = 0
    FOR i = 1 to ndata

        CALL funcs (x(i), a(), ymod, dyda(), ma)      ! Supplied by the user

        LET sig2i = 1 / (sig(i) * sig(i))
        LET dy = y(i) - ymod
        FOR j = 1 to mfit
            LET wt = dyda(lista(j)) * sig2i
            FOR k = 1 to j
                LET alpha(j, k) = alpha(j, k) + wt * dyda(lista(k))
            NEXT k
            LET beta(j, 1) = beta(j, 1) + dy * wt
        NEXT j
        LET chisq = chisq + dy * dy * sig2i
    NEXT i
    FOR j = 2 to mfit
        FOR k = 1 to j - 1
            LET alpha(k, j) = alpha(j, k)
        NEXT k
    NEXT j

END SUB