#### 21.3.1 Diagonal Matrix Functions ¶

*inv* and *pinv* can be applied to a diagonal matrix, yielding again
a diagonal matrix. *det* will use an efficient straightforward calculation
when given a diagonal matrix, as well as *cond*.
The following mapper functions can be applied to a diagonal matrix
without converting it to a full one:
*abs*, *real*, *imag*, *conj*, *sqrt*.
A diagonal matrix can also be returned from the *balance*
and *svd* functions.
The *sparse* function will convert a diagonal matrix efficiently to a
sparse matrix.