use ptrdiff_t as index type in Eigen
use ptrdiff_t as index type in Eigen

clab/dynet,clab/cnn,danielhers/dynet,clab/cnn,clab/dynet,shuheik/dynet,shuheik/dynet,shuheik/dynet,clab/cnn,clab/dynet,danielhers/dynet,clab/dynet,danielhers/dynet,danielhers/dynet,chunyang-wen/dynet,danielhers/dynet,clab/dynet,clab/dynet,shuheik/dynet,chunyang-wen/dynet,chunyang-wen/dynet,danielhers/dynet,shuheik/dynet,chunyang-wen/dynet,shuheik/dynet,clab/dynet,shuheik/dynet,danielhers/dynet