Sets the format for Koma to display numbers in. For example, calling
will cause println(someMatrix) to show more decimals (precision) than
format() must be called before a .toString() request to a Koma matrix in order to have any effect, but setting it will persist for all printing of matrices until called again with a different format string. The default setting is "long". Supported options are "long", "short", "verylong".