logm

Scilab Function
Last update : April 1993

logm - square matrix logarithm

### Calling Sequence

  `y=logm(x)`

### Parameters

- `x`: square matrix

### Description

`logm(x)` is the matrix logarithm of `x`. The result is complex if `x` is not positive or definite positive. If `x` is a symmetric matrix, then calculation is made by schur form. Otherwise, `x` is assumed diagonalizable. One has `expm(logm(x))=x`

### Examples

    A=[1,2;3,4];
    logm(A)
    expm(logm(A))
    A1=A*A';
    logm(A1)
    expm(logm(A1))
    A1(1,1)=%i;
    expm(logm(A1))

### See Also

`expm`, `log`,