Two constructors are available. The constructor without parameters allocates no memory. Another constructor takes the number of rows and columns in the matrix as parameters and allocates memory for the corresponding matrix representation. A new feature allows declaration of arrays with zero length.
Most member functions are self-explanatory.
The function assumes that the base of the rows and columns are 1. This function can be used to optimize indexing in loops. That function would require allocation and adjustment of an array of pointers. This function is useful when a Diffpack matrix is to be sent to a Fortran subroutine requiring a standard two-dimensional Fortran array. Especially, finite difference can be efficiently coded this way.