Octave矩阵运算（三）

矩阵的一些更复杂的运算

首先是矩阵的平方和矩阵元素的平方

>> A=[1,2,3;4,5,6;7,8,9]
A =

   1   2   3
   4   5   6
   7   8   9

>> A^2
ans =

    30    36    42
    66    81    96
   102   126   150

>> A.^2
ans =

    1    4    9
   16   25   36
   49   64   81

矩阵的每个元素求对数

>> help log
'log' is a built-in function from the file libinterp/corefcn/mappers.cc

 -- log (X)
     Compute the natural logarithm, 'ln (X)', for each element of X.

     To compute the matrix logarithm, see *note Linear Algebra::.

     See also: exp, log1p, log2, log10, logspace.

Additional help for built-in functions and operators is
available in the online version of the manual.  Use the command
'doc ' to search the manual index.

OK 输入help log可以看到直接把矩阵放入对数中，就是对每个元素取对数，同时注意这个log是自然对数。