Bend/FAQ.md

Known Issues and Frequently Asked Questions

Installation and Setup

Can I run this on Windows?

• We're still working on the windows support, for the moment, please use WSL2.

I'm getting a CUDA not available! error even though I have it installed?

• CUDA support is enable only during installation. If you first installed HVM and then installed CUDA and nvcc, please try to install HVM again.

I'm getting a Failed to launch kernels (error code invalid argument)! error.

• The current iteration of the hvm.cu was written with the RTX 4090 in mind, and won't work on older GPUs, since they contain about half of the newer GPUs shared memory, for better understanding please refer to HVM#283. We are working on support for older GPUs and will release it soon.

I get "Command bend not found" after installing, what do I do?

• If you are on Unix system (or WSL) then most likely bend did not add itself to the PATH variable in your rc file. To remedy this:
  • Determine if you are using bash or zsh (check for presence of ~/.bashrc or ~/.zshrc)
  • Make change to the relevant file by running echo -n 'export PATH=$PATH:$HOME/.cargo/bin' >> ~/.bashrc
    • use ~/.zshrc in place of ~/.bashrc in the case you are on zsh system
  • You will then need to run source ~/.bashrc or source ~/.zshrc for the changes to take effect immediately
  • Try running bend once more - it should work now!

I got an error when installing HVM on Linux

• If the error happens when compiling the CUDA runtime or contains anything regarding ccbin, please refer to HVM#291.

• If the error contains anything regarding libc missing, please refer to HVM#355

Can I run this on AMD/Intel/Apple GPUs?

• We plan on adding support to many other GPUs as soon as the CUDA version is sufficiently stable.

What GPUs are supported?

GPUs with >=96KB L1 cache per SM should work. This includes the following:

GPU	Tested?
RTX 4090	Yes
All Other Desktop 40 Series	No
All Desktop 30 Series	No
All Mobile 40 Series	No
All Mobile 30 Series	No

Using Bend

How do I use IO?

• IO is still being developed and is expected to come soon.

How to do FFI?

• Not as soon as basic IO, but planned or at least something similar to FFI.

Are there any Libraries, Packages etc?

• A package manager will be added soon.

Why are my numbers giving me wrong results?

Some possibilities:

• Your program is causing an overflow on 24-bit number values.
• Your program is doing operations on numbers of different types. (e.g. 2.0 + 1 is not allowed, you must use 2.0 + 1.0)
• Floating point numbers are currently bugged and are interpreted incorrectly in some cases.
• There's a bug with signed integers numbers that flips that sometimes flips the order of the operations.

I'm getting an error of failed assertion

• HVM currently has a bug in its conversion of f32 to f24 and it's unable to read the number 0.0. We already have a fix that we're working on.