If I add the line:
algorithm.parameter.observationsPerTreeFraction = 0.8;
to the example file df_reg_dense_batch.cpp which comes with the DAAL installation, the application will crash every time. I usually get an error message like this:
*** Error in `_results/gnu_intel64_parallel_a/df_reg_dense_batch.exe': double free or corruption (!prev): 0x00007f1c240034b0 ***
I have had this problem while working on a custom app and seen it with DAAL 2019 on macOS and also with DAAL 2020 on Linux. It crashes in all cases where the observationsPerTreeFraction is set to a number less than 1.0.
For the sake of a specific repro case:
Compile line: make libintel64 example=df_reg_dense_batch compiler=gnu
Example file: df_reg_dense_batch.cpp
Compiler: gcc (Ubuntu 5.4.0-6ubuntu1~16.04.12) 5.4.0 20160609
OS: Ubuntu 16.04.6 LTS
Thanks for looking into this!