Cmdstanr: Installing on Windows

[bbbales2]

I heard from someone that they had to do the special instructions to install the custom make in Rtools on Windows to get cmdstanr working. Is this still the case? If so can we add those directions to https://mc-stan.org/cmdstanr/ ?

[rok-cesnovar]

Did they do it recently (last month or so)?
current requirements for Windows are:

• install Rtools
• install_cmdstan()

Install cmdstan will let you know if anything is not setup correctly. You can also run check_cmdstan_toolchain() before that, though that is called inside install_cmdstan()

We can automatically do the following:

• install mingw32-make
• fix any PATH related issue

What we still currently have no automatic workaround for is:

• user has no permissions in the temp folder (very rare)
• the path where cmdstan is installed is too long (less rare but rare)

[bbbales2]

Ooo, okay, thanks for the feedback I'll try to clarify what happened.

[rok-cesnovar]

The version should be 0.2+ and you will have that features.

[bbbales2]

@rok-cesnovar Have you ever heard of something like this:

INFO: Could not find files for the given pattern(s).
cp bin/windows-stanc bin/stanc.exe

When someone runs:

install_cmdstan(overwrite = TRUE)

[rok-cesnovar]

This is just a warning from the cmdstan makefiles. We should clean it (I thought I cleaned up all of them). But it should not cause problems.

Please make a cmdstan issue, else we will forget.

Its also not related to the line below.

[ahartikainen]

the path where cmdstan is installed is too long (less rare but rare)

Windows has a possibility to use the inner path, which is always short + doesn't have any spaces.

Also there is a trick to add specific chars before the path which causes Windows to ignore long path checks. We use these in CmdStanPy

[rok-cesnovar]

Can you link me to what you use. I was wondering how we could use the old DOS-style short paths like "C:\Prog~1" but never found a way (didnt look hard enough I guess).

[ahartikainen]

We use this in CmdStanPy

def windows_short_path(path: str) -> str:
    """
    Gets the short path name of a given long path.
    http://stackoverflow.com/a/23598461/200291
    On non-Windows platforms, returns the path
    If (base)path does not exist, function raises RuntimeError
    """
    if platform.system() != 'Windows':
        return path

    if os.path.isfile(path) or (
        not os.path.isdir(path) and os.path.splitext(path)[1] != ''
    ):
        base_path, file_name = os.path.split(path)
    else:
        base_path, file_name = path, ''

    if not os.path.exists(base_path):
        raise RuntimeError(
            'Windows short path function needs a valid directory. '
            'Base directory does not exist: "{}"'.format(base_path)
        )

    import ctypes
    from ctypes import wintypes

    # pylint: disable=invalid-name
    _GetShortPathNameW = ctypes.windll.kernel32.GetShortPathNameW
    _GetShortPathNameW.argtypes = [
        wintypes.LPCWSTR,
        wintypes.LPWSTR,
        wintypes.DWORD,
    ]
    _GetShortPathNameW.restype = wintypes.DWORD

    output_buf_size = 0
    while True:
        output_buf = ctypes.create_unicode_buffer(output_buf_size)
        needed = _GetShortPathNameW(base_path, output_buf, output_buf_size)
        if output_buf_size >= needed:
            short_base_path = output_buf.value
            break
        else:
            output_buf_size = needed

    short_path = (
        os.path.join(short_base_path, file_name)
        if file_name
        else short_base_path
    )
    return short_path

https://github.com/stan-dev/cmdstanpy/blob/1e5f9491bdebc427022a093cf5a8343eb097df6a/cmdstanpy/utils.py#L833

And in installing we add this \\?\

if platform.system() == 'Windows':
    # fixes long-path limitation on Windows
    target = r'\\?\{}'.format(target)

r"" <-- raw string so we don't need to escape each \

https://github.com/stan-dev/cmdstanpy/blob/1e5f9491bdebc427022a093cf5a8343eb097df6a/cmdstanpy/install_cmdstan.py#L290

[ahartikainen]

You could probably use this

https://www.rdocumentation.org/packages/utils/versions/3.6.2/topics/shortPathName