LU decomposition of symetric pentadiagonal matrix in Python，,''' d,e,f =

LU decomposition of symetric pentadiagonal matrix in Python，,''' d,e,f =

''' d,e,f = LUdecomp5(d,e,f).    LU decomposition of symetric pentadiagonal matrix    [f\e\d\e\f]. On output {d},{e} and {f} are the    diagonals of the decomposed matrix.    x = LUsolve5(d,e,f,b).    Solves [f\e\d\e\f]{x} = {b}, where {d}, {e} and {f}    are the vectors returned from LUdecomp5.    '''def LUdecomp5(d,e,f):    n = len(d)    for k in range(n-2):        lam = e[k]/d[k]        d[k+1] = d[k+1] - lam*e[k]        e[k+1] = e[k+1] - lam*f[k]        e[k] = lam        lam = f[k]/d[k]        d[k+2] = d[k+2] - lam*f[k]        f[k] = lam    lam = e[n-2]/d[n-2]    d[n-1] = d[n-1] - lam*e[n-2]    e[n-2] = lam    return d,e,fdef LUsolve5(d,e,f,b):    n = len(d)    b[1] = b[1] - e[0]*b[0]    for k in range(2,n):        b[k] = b[k] - e[k-1]*b[k-1] - f[k-2]*b[k-2]    b[n-1] = b[n-1]/d[n-1]    b[n-2] = b[n-2]/d[n-2] - e[n-2]*b[n-1]    for k in range(n-3,-1,-1):        b[k] = b[k]/d[k] - e[k]*b[k+1] - f[k]*b[k+2]    return b