FastK: Segmentation fault with small data

[junaruga]

Hello, On the latest master f18a4e6d2207539f7b84461daebc54530a9559b0 , I was trying to test the FastK with a small test data. Then I got the following Segmentation fault. Do you have any idea about how to fix it? Thank you.

$ pwd
/home/jaruga/git/FASTK

$ gcc --version
gcc (GCC) 12.2.1 20220819 (Red Hat 12.2.1-1)
Copyright (C) 2022 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ make

$ cat fastk_source.fasta 
>FastK input source
ACTG

$ ./FastK -v fastk_source.fasta 

Partitioning 1 .fasta file into 4 parts
  File is so small will use only 1 thread 

Determining minimizer scheme & partition for fastk_source

FastK: Warming Sequences are on average smaller than 1.5x k-mer size!
  Estimate -0.036K 40-mers
  Handling data in a single block
  Using 5-minimizers with 1024 core prefixes

Phase 1: Partitioning K-mers into 1 Super-mer Files

  There are 1 reads totalling 4 bps

     Part:  40-mer  super-mers  ave. length
        0:       0           0           NA
      Sum:       0           0           NA

      Range 0 - 0

  Resources for phase:  0.000u  0.001s  0.001w  127.8%

Phase 2: Sorting & Counting K-mers in 1 blocks

  Processing block 1: Sorting super-mers     Segmentation fault (core dumped)