Indxvec

Description

Indxvec is a self-contained crate: it has no dependencies. It is used by higher level crates sets and rstats.

The tools included are: efficient ranking, sorting, merging, searching, set operations and indices manipulations. They are applicable to generic slices &[T]. Thus they will work on Rust primitive end types, such as f64. They can also work on slices holding any arbitrarily complex end type T, as long as the required traits, mostly just PartialOrd and/or Copy, are implemented for T.

Usage

Import into your source file(s) from the top crate level:

struct MinMax: a convenience wrapper for returning the minimum and the maximum values of a vector or slice and their indices
macro here: for more informative error reports
functions wi,wv to pretty print in green a single generic item and a generic vector, respectively.
function printvv to pretty-print a generic vector of vectors.

Import trait Indices

Trait Indices is implemented on type &[usize], i.e. slices of subscripts to slices and vectors (more details below).

Import functions from module merge.rs

These functions usually take generic slices of data &[T] as arguments and produce new index vectors and/or other results (more details below).

The following use statement imports everything from indxvec:

use indxvec::{MinMax,here,wv,wi,printvv,Indices,merge::*};

It is highly recommended to read and run tests/tests.rs to learn from examples of usage. Use a single thread to run them. It may be a bit slower but it will write the results in the right order:

cargo test --release -- --test-threads=1 --nocapture --color always

Functions

are in module src/merge.rs. They mostly take some generic slice(s) &[T] and produce the indices into them of type Vec<usize>, onto which the methods of the Indices trait can be conveniently chained:

// Reverse a generic slice by reverse iteration.
pub fn revs<T>(s: &[T]) -> Vec<T> where T: Copy

/// Finds minimum, minimum's first index, maximum, maximum's first index 
pub fn minmax<T>(v:&[T])  -> MinMax<T> where T: PartialOrd+Copy

/// Removes repetitions from an explicitly ordered set.
pub fn sansrepeat<T>(s:&[T]) -> Vec<T> where T: PartialOrd+Copy

/// Finds the first occurence of item `m` in slice `s` by full iteration.
pub fn member<T>(s:&[T], m:T) -> Option<usize> where T: PartialOrd+Copy 

/// Binary search of an explicitly sorted list (in ascending order).
pub fn memsearch<T>(s:&[T], val: T)  -> Option<usize> where T: PartialOrd

/// Binary search of an explicitly sorted list (in descending order).
pub fn memsearchdesc<T>(s:&[T], val: T)  -> Option<usize> where T: PartialOrd

/// Binary search of an indexed list (in ascending order).
pub fn memsearch_indexed<T>(s:&[T], i:&[usize], val: T)  -> Option<usize> where T: PartialOrd 

/// Binary search of an explicitly sorted list in ascending order.
pub fn binsearch<T>(s:&[T], val:T)  -> usize where T: PartialOrd

/// Binary search of an explicitly sorted list in descending order.
pub fn binsearchdesc<T>(s:&[T], val:T) -> usize where T: PartialOrd 

/// Unites two ascending explicitly sorted generic slices
pub fn unite<T>(v1: &[T], v2: &[T]) -> Vec<T> where T: PartialOrd+Copy

/// Unites two ascending index-sorted generic vectors.
pub fn unite_indexed<T>(v1: &[T], ix1: &[usize], v2: &[T], ix2: &[usize]) -> Vec<T> where T: PartialOrd+Copy

/// Intersects two ascending explicitly sorted generic vectors.
pub fn intersect<T>(v1: &[T], v2: &[T]) -> Vec<T> where T: PartialOrd+Copy

/// Intersects two ascending index-sorted generic vectors. 
pub fn intersect_indexed<T>(v1: &[T], ix1: &[usize], v2: &[T], ix2: &[usize]) -> Vec<T> where T: PartialOrd+Copy

/// Sets difference: deleting elements of the second from the first.
pub fn diff<T>(v1: &[T], v2: &[T]) -> Vec<T> where T: PartialOrd+Copy

/// Sets difference: deleting elements of the second from the first.
pub fn diff_indexed<T>(v1: &[T], ix1: &[usize], v2: &[T], ix2: &[usize]) -> Vec<T> where T: PartialOrd+Copy

/// Merges two ascending sorted generic vectors.
pub fn merge<T>(v1: &[T], v2: &[T]) -> Vec<T> where T: PartialOrd+Copy

/// Merges two ascending sort indices.
pub fn merge_indexed<T>(v1:&[T], idx1: &[usize], v2: &[T], idx2: &[usize]) -> ( Vec<T>,Vec<usize> ) where T: PartialOrd+Copy

/// Merges the sort indices of two concatenated vectors.
fn merge_indices<T>(s: &[T], idx1:&[usize], idx2:&[usize]) -> Vec<usize>
    where T: PartialOrd+Copy

/// Doubly recursive non-destructive merge sort.
pub fn mergesort<T>(s:&[T], i:usize, n:usize) -> Vec<usize> 
    where T: PartialOrd+Copy

/// A wrapper for mergesort, to obtain the sort index
pub fn sortidx<T>(s:&[T]) -> Vec<usize> where T:PartialOrd+Copy

/// Immutable sort. Returns new sorted vector (ascending or descending)
pub fn sortm<T>(s:&[T], ascending:bool) -> Vec<T> where T: PartialOrd+Copy

/// Fast ranking of many T items, with only `n*(log(n)+1)` complexity
pub fn rank<T>(s:&[T], ascending:bool) -> Vec<usize> where T:PartialOrd+Copy

Trait Indices

The methods of this trait are implemented for slices of subscripts, i.e. they take the type &[usize] as input (self) and produce new index Vec<usize>, new data vector Vec<T>, or other results as appropriate:

/// Methods to manipulate indices of `Vec<usize>` type.
pub trait Indices { 
    /// Reverse an index slice by simple reverse iteration.
    fn revindex(self) -> Vec<usize>; 
    /// Invert an index.
    fn invindex(self) -> Vec<usize>;
    /// complement of an index - turns ranks from/to 
    /// ascending/descending
    fn complindex(self) -> Vec<usize>;
    /// Collect values from `v` in the order of index in self.
    fn unindex<T: Copy>(self, v:&[T], ascending:bool) -> Vec<T>;
    /// Collects values from v, as f64s, 
    /// in the order given by self index.    
    fn unindexf64<T: Copy>(self, v:&[T], ascending: bool) -> 
        Vec<f64> where f64:From<T>;
    /// Pearson's correlation coefficient of two slices, 
    /// typically the ranks.  
    fn ucorrelation(self, v: &[usize]) -> f64; 
    /// Potentially useful clone-recast of &[usize] to Vec<f64> 
    fn indx_to_f64 (self) -> Vec<f64>;
}

Release Notes (Latest First)

Version 1.0.1 - Some code style tidying up. Added function binsearchdesc for completeness and symmetry with binsearch.

Version 1.0.0 - indxvec has been stable for some time now, so it gets promoted to v1.0.0. There are some improvements to README.md to mark the occasion.

Version 0.2.12 - added utility function printvv to prettyprint vectors of vectors.

Version 0.2.11 - added some badges and improved readme.

Version 0.2.9 - added struct MinMax for returning values from function 'minmax' and displaying them. Removed function wt used previously for displaying them as tuples.

Version 0.2.6 - added unindexf64 for convenience. Same as unindex but the output is always converted to Vec<f64>.

Version 0.2.5 - added memsearchdesc_indexed = binary search of a descending indexed set.

Version 0.2.4 - added helper function wt = write tuple. Added memsearchdesc = binary search of a descending set.

Version 0.2.3 - general tidying up and readme update.

Version 0.2.2 - replaced GV and GI with functions wv and wi respectively. Added revindex to Indices trait, so that it can be functionally chained with its other methods.

Version 0.2.1 - moved GI from rstats to here. Fixed minmax.