Cannot run example

[TernaryM01]

I'm using WSL 2 Ubuntu 20.04 inside Windows 10. I have installed SoPlex, OSI, and Fast-Downward with LP support. I have tested my downward installation by finding some simple PDDL task and then running ./fast-downward.py problem.pddl task.pddl --search "astar(lmcut())" The solver found a solution. So there isn't an issue with my downward installation.

I installed fast-downward (this repo Haskell interface) using cabal: cabal install fast-downward It installed version 0.2.1.0 (latest).

Then, I downloaded the Gripper.hs example from this repo, and deleted the line: module FastDownward.Examples.Gripper where I saved it, and compiled it with: ghc -o Gripper Gripper.hs It compiled successfully, so I ran it: ./Gripper

The only output is the error message: Gripper: downward: createProcess: runInteractiveProcess: exec: inappropriate type (Not a directory)

[mknorps]

I had the same error. My Haskell program did not see downward library.

Fix it by adding downward executable file path (which is not the Python script, but the program in bin) to the shell you run it on. For me it was a line in .zshrc pointing to a place where downward library was saved and executables were build:

export PATH="{PATH_TO_DOWNWARD}/builds/release/bin:$PATH"