Vec B_vecs[] = frb.vecs();
long A_rows = fra.numRows();
long B_rows = frb.numRows();
long start = chks[0].start();
int chunkSize = chks[0].len();
ValueString vstr = new ValueString();
for (int r = 0; r < chunkSize; r++) {
for (int c = 0; c < chks.length; c++) {
if (r + start < A_rows) {
chks[c].set0(r, A_vecs[c].at(r + start));