BSeasy_A - Given A in a standard numerical format, construct the
sparse A that we need for BlockSolve. This routine is
particularly useful for matrices created in Fortran.
The rows on a processor must be contiguous in the
global numbering. If they are not, then other BlockSolve
routines must be called to construct the matrix for BlockSolve.
Arrays are indexed starting with 0.
The values in a row must be sorted according to column number.
start_num - the global number of the first row on this proc.
n - the number of rows on *this* processor.
rp - an array of indices of length n+1 -- rp(i) gives the beginning
entry of row i in cval and aval.
cval - an array of column numbers. cval[i] gives the column number
of entry i in aval.
aval - an array of the nonzero values in the sparse matrix.
procinfo - the usual processor information