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.