Four elementwise functions are provided: Mexp(),
Mabs(), Msqrt(), and
Mlog()..
These take the elementwise exponent, absolute value, square
root, and natural logarithm. Argument ranges are checked in
the square root and logarithm functions. If an invalid
argument is given, the program terminates through the error
function, Dispatch->Nrerror(). This function was defined a
returning a double so that it could be used in the ternary
operator as an error branch. The functions return
references to a VMatrix.