traceproduct.m

来自「人工神经网络的源码编程」· M 代码 · 共 26 行

function t = traceProduct(X, Y)
%  t = traceProduct(X, Y)
%
%  Outputs the trace of the product of X and Y.
%  Faster than trace(X*Y).
%
%  Inputs
%
%    X    matrix (m-by-n)
%    Y    matrix (m-by-n)
%
%  Output
%
%    t    scalar

[m,n] = size(X);
[p,q] = size(Y);

if m ~= q | n ~= p
  error('traceProduct: bad dimensions')
  return
end

% use the fast diagonal of a product routine
t = sum(diagProduct(X, Y));