totalTileCount = nSx*nSy*nPx*nPy
theTag = TagW0*totalTileCount+tileNo(bi,bj)-1
theTag = TagE0*totalTileCount+tileNo(bi,bj)-1
theTag = TagN0*totalTileCount+tileNo(bi,bj)-1
theTag = TagS0*totalTileCount+tileNo(bi,bj)-1
theTag = TagW0*totalTileCount+tileNoE(bi,bj)-1
theTag = TagE0*totalTileCount+tileNoW(bi,bj)-1
theTag = TagS0*totalTileCount+tileNoN(bi,bj)-1
theTag = TagN0*totalTileCount+tileNoS(bi,bj)-1
INTEGER totalTileCount