Fix uninitialized effective lengths for ref.

[haowenz]

@mourisl Please be more careful when adding uninitialized variables as they are dangerous and cause issues that are not easy to debug.

[mourisl]

chromap/src/sequence_batch.h

Lines 18 to 20 in 266c513

	effective_range_[0] = 0;
	effective_range_[1] = -1;
	effective_range_[2] = 1;

I did the initialization in the constructor function here. Not sure why the fix works, and there might be another reason for #62 ?

[haowenz]

You are right. To me the bug was likely caused by efffective_length[1]=0, which makes the length of sequences 0, thereby getting 0 minimizers. Otherwise, the code would fail somewhere else. As no others has had this issue, I think it is possible that somehow this user's compiler has a bug and did not call the default constructor. We can keep this open for a while and see.

[haowenz]

Did a bit more search and found a interesting post here. It is likely that in some rare case with some compilers the default constructor is somehow not called. Let us merge this and later refactor this class to use initializer list later.