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//
// A rust binding for the GSL library by Guillaume Gomez (guillaume1.gomez@gmail.com)
//
/*!
#Multisets
This chapter describes functions for creating and manipulating multisets. A multiset c is represented by an array of k integers in the
range 0 to n-1, where each value c_i may occur more than once. The multiset c corresponds to indices of k elements chosen from an n element
vector with replacement. In mathematical terms, n is the cardinality of the multiset while k is the maximum multiplicity of any value.
Multisets are useful, for example, when iterating over the indices of a k-th order symmetric tensor in n-space.
!*/
use ffi;
use enums;
use std::io::Result as IoResult;
use c_vec::CSlice;
use std::io::Write;
pub struct MultiSet {
c: *mut ffi::gsl_multiset,
data: CSlice<u64>
}
impl MultiSet {
/// This function allocates memory for a new multiset with parameters n, k. The multiset is not initialized and its elements are
/// undefined. Use the function gsl_multiset_calloc if you want to create a multiset which is initialized to the lexicographically
/// first multiset element. A null pointer is returned if insufficient memory is available to create the multiset.
pub fn new(n: u64, k: u64) -> Option<MultiSet> {
let tmp = unsafe { ffi::gsl_multiset_alloc(n, k) };
if tmp.is_null() {
None
} else {
unsafe {
if (*tmp).data.is_null() {
Some(MultiSet {
c: tmp,
// dirty trick to avoid a failure
data: CSlice::new(tmp as *mut u64, 0usize)
})
} else {
Some(MultiSet {
c: tmp,
data: CSlice::new((*tmp).data, (*tmp).k as usize)
})
}
}
}
}
/// This function allocates memory for a new multiset with parameters n, k and initializes it to the lexicographically first multiset
/// element. A null pointer is returned if insufficient memory is available to create the multiset.
pub fn new_init(n: u64, k: u64) -> Option<MultiSet> {
let tmp = unsafe { ffi::gsl_multiset_calloc(n, k) };
if tmp.is_null() {
None
} else {
unsafe {
if (*tmp).data.is_null() {
Some(MultiSet {
c: tmp,
// dirty trick to avoid a failure
data: CSlice::new(tmp as *mut u64, 0usize)
})
} else {
Some(MultiSet {
c: tmp,
data: CSlice::new((*tmp).data, (*tmp).k as usize)
})
}
}
}
}
/// This function initializes the multiset c to the lexicographically first multiset element, i.e. 0 repeated k times.
pub fn init_first(&self) {
unsafe { ffi::gsl_multiset_init_first(self.c) }
}
/// This function initializes the multiset c to the lexicographically last multiset element, i.e. n-1 repeated k times.
pub fn init_last(&self) {
unsafe { ffi::gsl_multiset_init_last(self.c) }
}
/// This function copies the elements of the multiset self into the multiset dest. The two multisets must have the same size.
pub fn copy(&self, dest: &MultiSet) -> enums::value::Value {
unsafe { ffi::gsl_multiset_memcpy(dest.c, self.c) }
}
/// This function returns the value of the i-th element of the multiset c. If i lies outside the allowed range of 0 to k-1 then the
/// error handler is invoked and 0 is returned.
pub fn get(&self, i: u64) -> u64 {
unsafe { ffi::gsl_multiset_get(self.c, i) }
}
/// This function returns the range (n) of the multiset self.
pub fn n(&self) -> u64 {
unsafe { ffi::gsl_multiset_n(self.c) }
}
/// This function returns the number of elements (k) in the multiset self.
pub fn k(&self) -> u64 {
unsafe { ffi::gsl_multiset_k(self.c) }
}
/// This function returns a pointer to the array of elements in the multiset self.
pub fn data<'r>(&'r mut self) -> &'r mut [u64] {
self.data.as_mut()
}
/// This function checks that the multiset self is valid. The k elements should lie in the range 0 to n-1, with each value occurring in
/// nondecreasing order.
pub fn valid(&self) -> enums::value::Value {
unsafe { ffi::gsl_multiset_valid(self.c) }
}
/// This function advances the multiset self to the next multiset element in lexicographic order and returns ::Value::Success. If no
/// further multisets elements are available it returns enums::value::Failure and leaves self unmodified. Starting with the first multiset and
/// repeatedly applying this function will iterate through all possible multisets of a given order.
pub fn next(&self) -> enums::value::Value {
unsafe { ffi::gsl_multiset_next(self.c) }
}
/// This function steps backwards from the multiset self to the previous multiset element in lexicographic order, returning ::Value::Success.
/// If no previous multiset is available it returns enums::value::Failure and leaves self unmodified.
pub fn prev(&self) -> enums::value::Value {
unsafe { ffi::gsl_multiset_prev(self.c) }
}
pub fn print(&self, writer: &mut Write) -> IoResult<()> {
for value in self.data.as_ref().iter() {
match write!(writer, " {}", *value) {
Ok(_) => {},
Err(e) => return Err(e),
}
}
Ok(())
}
}
impl Drop for MultiSet {
fn drop(&mut self) {
unsafe { ffi::gsl_multiset_free(self.c) };
self.c = ::std::ptr::null_mut();
}
}
impl ffi::FFI<ffi::gsl_multiset> for MultiSet {
fn wrap(c: *mut ffi::gsl_multiset) -> MultiSet {
unsafe {
if (*c).data.is_null() {
MultiSet {
c: c,
// dirty trick to avoid a failure
data: CSlice::new(c as *mut u64, 0usize)
}
} else {
MultiSet {
c: c,
data: CSlice::new((*c).data, (*c).k as usize)
}
}
}
}
fn unwrap(c: &MultiSet) -> *mut ffi::gsl_multiset {
c.c
}
}