futhark-cuda - compile Futhark to CUDA

       2013-2020, DIKU, University of Copenhagen

0.25.27                                           Mar 02, 2025                                   FUTHARK-CUDA(1)

futharkcuda  translates  a  Futhark program to C code invoking CUDA kernels, and either compiles that C
       code with a C compiler to an executable binary program, or produces a .h and .c file that can  be  linked
       with other code. The standard Futhark optimisation pipeline is used.

       futharkcuda uses -lcuda-lcudart-lnvrtc to link.  If using --library, you will need to do the same when
       linking the final binary.

       The  generated CUDA code can be called from multiple CPU threads, as it brackets every API operation with
       cuCtxPushCurrent() and cuCtxPopCurrent().

       If run without --library, futharkcuda will invoke a C compiler to compile the generated C program into a
       binary.  This only works if the C compiler can find the necessary CUDA libraries.  On most systems,  CUDA
       is  installed  in /usr/local/cuda, which is usually not part of the default compiler search path. You may
       need to set the following environment variables before running futharkcuda:

          LIBRARY_PATH=/usr/local/cuda/lib64
          LD_LIBRARY_PATH=/usr/local/cuda/lib64/
          CPATH=/usr/local/cuda/include

       At runtime the generated program must be able to find the CUDA installation directory, which is  normally
       located  at  /usr/local/cuda.  If you have CUDA installed elsewhere, set any of the CUDA_HOME, CUDA_ROOT,
       or CUDA_PATH environment variables to the proper directory.

CC
          The C compiler used to compile the program.  Defaults to cc if unset.

       CFLAGS
          Space-separated list of options passed to the C compiler.  Defaults to -O-std=c99 if unset.

       Generated executables accept the same options as those generated by futhark-c. The -t option  behaves  as
       with futhark-opencl.

       The following additional options are accepted.

       -h, --help
              Print help text to standard output and exit.

       --default-thread-block-size=INT
              The default size of thread blocks that are launched.  Capped to the hardware limit if necessary.

       --default-num-thread-blocks=INT
              The default number of thread blocks that are launched.

       --default-threshold=INT
              The  default  parallelism  threshold  used  for  comparisons  when selecting between code versions
              generated by incremental flattening.  Intuitively, the amount of parallelism  needed  to  saturate
              the GPU.

       --default-tile-size=INT
              The  default tile size used when performing two-dimensional tiling (the workgroup size will be the
              square of the tile size).

       --dump-cuda=FILE
              Don’t run the program, but instead dump the embedded CUDA kernels to the indicated  file.   Useful
              if you want to see what is actually being executed.

       --dump-ptx=FILE
              Don’t  run  the  program, but instead dump the PTX-compiled version of the embedded kernels to the
              indicated file.

       --load-cuda=FILE
              Instead of using the embedded CUDA kernels, load them from the indicated file.

       --load-ptx=FILE
              Load PTX code from the indicated file.

       --nvrtc-option=OPT
              Add an additional build option to the string passed to NVRTC.  Refer to the CUDA documentation for
              which options are supported.  Be careful - some options can easily result in invalid results.

       futhark-cuda - compile Futhark to CUDA

       Accepts the same options as futhark-c.

futhark-opencl

       futhark cuda [options…] <program.fut>