n-Psi(n+1)-eulergamma
EulerGamma=0.57721566490153.高斯常数
psi就复杂了.你要去查查这个函数,一般给你说不清,下边是英文的解释.psi(1)=-EulerGamma
Y = psi(X) evaluates the function for each element of array X.X must be real and nonnegative.The function,also known as the digamma function,is the logarithmic derivative of the gamma function Y = psi(k,X) evaluates the kth derivative of at the elements of X.psi(0,X) is the digamma function,psi(1,X) is the trigamma function,psi(2,X) is the tetragamma function,etc.Y = psi(k0:k1,X) evaluates derivatives of order k0 through k1 at X.Y(k,j) is the (k-1+k0)th derivative of ,evaluated at X(j).