For each SIMD vector type, several words are defined, where type is the type in question:
WordStack effectDescription
type-with( x -- simd-array )creates a new instance where all components are set to a single scalar
type-boa( ... -- simd-array )creates a new instance where components are read from the stack
type-cast( simd-array -- simd-array' )creates a new SIMD array where the underlying data is taken from another SIMD array, with no format conversion
>type( seq -- simd-array )creates a new instance initialized with the elements of an existing sequence, which must have the correct length
type{type{ elements... }parsing word defining literal syntax for an SIMD vector; the correct number of elements must be given

To actually perform vector arithmetic on SIMD vectors, use Vector operations words.

See also
C type specifiers