Find the global bounds on the eigenvalues of a tridiagomal matrix in Python，,''' lamMin,l

Find the global bounds on the eigenvalues of a tridiagomal matrix in Python，,''' lamMin,l

''' lamMin,lamMax = gerschgorin(d,c).    Applies Gerschgorin's theorem to find the global bounds on    the eigenvalues of a tridiagomal matrix [A] = [c\d\c].'''def gerschgorin(d,c):    n = len(d)    lamMin = d[0] - abs(c[0])    lamMax = d[0] + abs(c[0])    for i in range(1,n-1):        lam = d[i] - abs(c[i]) - abs(c[i-1])        if lam < lamMin: lamMin = lam        lam = d[i] + abs(c[i]) + abs(c[i-1])        if lam > lamMax: lamMax = lam    lam = d[n-1] - abs(c[n-2])    if lam < lamMin: lamMin = lam    lam = d[n-1] + abs(c[n-2])    if lam > lamMax: lamMax = lam    return lamMin,lamMax