  ^ ^                 ^ ^
=(o.o)=  ~byakuren  =(o.o)=
  m m                 m m

Troubleshooting (`flowlog.c`)

Stack overflows / crashes under OR-par

OR-par workers run deep recursive solver code and can overflow small pthread stacks.

Try:

Reduce worker count: --threads N
Override stack size: FLOWLOG_ORPAR_STACK_SIZE=33554432 (32 MiB)
Cap OR-par workers: FLOWLOG_ORPAR_MAX_WORKERS=N

“It’s only using one core”

Parallelism is enabled by default (flowlog_parallel_profile=fast).

If you only see one core in use, check:

Your program did not turn parallelism off via directives:
- :- set_prolog_flag(flowlog_parallel_profile, off).
- :- set_prolog_flag(flowlog_parallel_or, off).
You are not running with --threads 1 (or FLOWLOG_N_CPUPROC=1).
The workload actually has large enough choicepoints for OR-par to help:
- Flowlog only spawns OR-par for “big” alternative sets (by default, very small choicepoints stay sequential to avoid overhead).
- Enable OR-par logs (FLOWLOG_DEBUG_ORPAR=all) to see whether work is being spawned.
You are not benchmarking on the interpreter engine by accident:
- Prefer --engine wamvm (default) or try --engine wam for the WAM-lite engine.

Also confirm Flowlog sees your CPU count:

FLOWLOG_N_CPUPROC is not set to 1
you did not pass --threads 1

Notes:

Some workloads do not have large enough choicepoints for OR-par to help.
For ordered mode (flowlog_parallel_profile=iso), Flowlog may limit parallelism to preserve classic enumeration order.
OR-par is heuristic-driven; enable debug logs to confirm spawning:
- FLOWLOG_DEBUG_ORPAR=1 (or 2) and optionally FLOWLOG_DEBUG_ORPAR_LOG=/tmp/flowlog_orpar.log

REPL editing keys don’t work

The line editor is enabled only when stdin/stdout are TTYs. If you run the REPL via redirected input/output, Flowlog falls back to plain line reads.

History file issues

History is written to:

~/.flowlog_history by default

Override with:

FLOWLOG_HISTORY_FILE=/path/to/file

“My terminal output is staircasing / newlines look wrong”

If your terminal looks like output is indented further and further to the right, your terminal may have been left in a bad termios state after a crash.

Fix:

reset

“`[file].` doesn’t load my program”

Flowlog supports the common top-level consult shorthand, but it only works when the file can be resolved on disk.