futhark dataset [options…]


Generate random values in Futhark syntax, which can be useful when generating input datasets for program testing. All Futhark primitive types are supported. Tuples are not supported. Arrays of specific (non-random) sizes can be generated. You can specify maximum and minimum bounds for values, as well as the random seed used when generating the data. The generated values are written to standard output.

If no -g/--generate options are passed, values are read from standard input, and printed to standard output in the indicated format. The input format (whether textual or binary) is automatically detected.

Returns a nonzero exit code if it fails to write the full output.


-b, --binary

Output data in binary Futhark format (must precede –generate).

-g type, --generate type

Generate a value of the indicated type, e.g. -g i32 or -g [10]f32.

The type may also be a value, in which case that literal value is generated.

-s int

Set the seed used for the RNG. 1 by default.


Set inclusive lower and upper bounds on generated values of type T. T is any primitive type, e.g. i32 or f32. The bounds apply to any following uses of the -g option.

You can alter the output format using the following flags. To use them, add them before data generation (–generate):


Output data in text format (must precede –generate). Default.

-t, --type

Output the types of values (textually) instead of the values themselves. Mostly useful when reading values on stdin.


Generate a 4 by 2 integer matrix:

futhark dataset -g [4][2]i32

Generate an array of floating-point numbers and an array of indices into that array:

futhark dataset -g [10]f32 --i64-bounds=0:9 -g [100]i64

To generate binary data, the --binary must come before the --generate:

futhark dataset --binary --generate=[42]i32

Create a binary data file from a data file:

futhark dataset --binary < any_data > binary_data

Determine the types of values contained in a data file:

futhark dataset -t < any_data


futhark-test, futhark-bench