assertion failed: [All values in memory_sequence_length must greater than zero.

[nashid]

NMT is failing at the time of training:

InvalidArgumentError (see above for traceback): assertion failed: [All values in memory_sequence_length must greater than zero.] [Condition x > 0 did not hold element-wise:] [x (IteratorGetNext:1) = ] [8 8 8...]

[[Node: dynamic_seq2seq/decoder/decoder/while/BasicDecoderStep/decoder/attention/assert_positive/assert_less/Assert/Assert = Assert[T=[DT_STRING, DT_STRING, DT_STRING, DT_INT32], summarize=3, _device="/job:localhost/replica:0/task:0/device:CPU:0"](dynamic_seq2seq/decoder/decoder/while/BasicDecoderStep/decoder/attention/assert_positive/assert_less/All, 

dynamic_seq2seq/decoder/decoder/while/BasicDecoderStep/decoder/attention/assert_positive/assert_less/Assert/Assert/data_0, dynamic_seq2seq/decoder/decoder/while/BasicDecoderStep/decoder/attention/assert_positive/assert_less/Assert/Assert/data_1, dynamic_seq2seq/decoder/decoder/while/BasicDecoderStep/decoder/attention/assert_positive/assert_less/Assert/Assert/data_2, dynamic_seq2seq/decoder/decoder/while/BasicDecoderStep/decoder/attention/assert_positive/assert_less/Less/Enter)]]

I don't have any empty line in the train, test, or validation dataset. Any ideas?

[nashid]

Found the issue, some input line consisted of multiple spaces which NMT failed to handle i.e.:

aa.  a. a. aa
abc         abd
zcc dwawdfeef

Apparently, here line2 was the issue.