`make-sparse-vector``#!optional``DEFAULT`procedure`sparse-vector?``x`procedure`sparse-vector-ref``sparse-vector``k`procedure`sparse-vector-set!``sparse-vector``k``value`procedure`sparse-vector->list``sparse-vector`procedure`make-sparse-vector`,`sparse-vector-ref`and`sparse-vector-set!`are analogous to`make-vector`,`vector-ref`and`vector-set!`, except that the indices passed to`sparse-vector-ref`and`sparse-vector-set!`can be arbitrarily large.The optional

`DEFAULT`argument to the`make-sparse-vector`procedure specifies the default value for indices whose elements have not been set. If the element at index`i`has not been set,`(sparse-vector-ref i)`returns`DEFAULT`or #f, if`DEFAULT`was not specified when creating the vector.`sparse-vector->list`is for debugging: It returns a list of the consecutive elements in a sparse vector from 0 to the highest element that has been set. Note that the list will also include all the #f elements for the unset elements.`(set! (sparse-vector-ref sparse-vector index) value)`is supported.