Indxvec

Description

This crate is lightweight and has no dependencies.

The facilities provided are:

• ranking, sorting, merging, searching, indexing, selecting, partitioning
• general operations on/with indices
• set operations
• printing of generic slices and slices of vectors
• macro for easy error reporting

Usage

Auxiliay functions and constants

use indxvec::{GR,RD,UN,MinMax,here,tof64};

Traits Indices and/or Printing

use indxvec::{Indices,Printing};

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

Trait Printing provides utility methods to stringify (serialise for printing) generic slices and slices of vecs. Optionally, it enables printing in bold green and red for adding emphasis (see tests/tests.rs).

Functions from merge.rs

use indxvec::{merge::*};

These functions 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.

The following will import everything

use indxvec::{GR,RD,UN,MinMax,here,tof64,merge::*,Indices,Printing};

Testing

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

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 - turns a sort order into rank order and vice-versa
    fn invindex(self) -> Vec<usize>;
    /// complement of an index - reverses the ranking order
    fn complindex(self) -> Vec<usize>;
    /// Collect values from `v` in the order of index in self. Or opposite order.
    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 ranks.  
    fn ucorrelation(self, v: &[usize]) -> f64;
    /// Potentially useful clone-recast of &[usize] to Vec<f64>
    fn indx_to_f64 (self) -> Vec<f64>;
}

Trait Printing

This trait is implemented for generic individual items T, for slices &[T] and for slices of vecs &[Vec<T>]. Note that these types are normally unprintable in Rust.

The methods of this trait .gr(), .red(), .blue(), .wvec(&mut f) and .to_str() convert all these generic vector objects to printable strings. The last two are uncoloured and can be used to write to files; wvec also passes on io::Error(s) For example:

println!("My pretty vec: {}", myvec.to_str());

It is also possible to import these constants: use indxvec::{RD,GR,BL,UN}; and then use them in any formatting strings directly, e.g.: "{RD} my important output: {} {UN}" will print everything so bracketed in red. Switching colours:
println!("{GR}green text, {RD}red warning, {BL}feeling blue{UN}");

Note that all of these methods and interpolations set their own colour regardless of the previous settings.

Interpolating {UN} resets the terminal to its default foreground rendering. UN is automatically appended at the end of strings produced by .gr(),.red() and .green() methods. Be careful to always close with one of these three, or {UN}, otherwise all the following output will continue with the last selected colour foreground rendering.

/// Trait to serialize slices of generic items &[T] (vectors)
/// and slices of Vecs &[Vec<T>] (matrices).
/// All are converted into printable strings.
pub trait Printing<T> {
    /// Method to serialize and render the resulting string in bold green.
    /// This is the default implementation applicable to all types that
    /// trait `Printing` is implemented for
    fn gr(self) -> String  where  Self: Sized {
        format!("{GR}{}{UN}", self.to_str())
    }
    /// Method to serialize and render the resulting string in bold red.
    fn red(self) -> String  where  Self: Sized,    {
        format!("{RD}{}{UN}", self.to_str())
    }
    /// Method `write vector(s) to file f`
    fn wvec(self,f:&mut File) -> Result<(), io::Error> where Self: Sized { 
        Ok(write!(*f,"{} ", self.to_str())?) 
    }
    
    /// Method to serialize generic items, slices, and slices of Vecs.
    /// Implementation code is in printing.rs
    /// Can be also implemented on any other types.
    fn to_str(self) -> String;
}

Functions

Nota bene: hashsort really wins on longer Vecs. For about one thousand items upwards it is on average about 25% faster than the best Rust sort.

Signatures of public functions in module src/merge.rs

/// New trivial index for v in the existing order: 0..v.len()
pub fn newindex(n:usize) -> Vec<usize>;

/// Maximum value T of slice &[T]
pub fn maxt<T>(v:&[T]) -> T where T:PartialOrd+Copy;

/// Minimum value T of slice &[T]
pub fn mint<T>(v:&[T]) -> T where T:PartialOrd+Copy;

/// Minimum and maximum (T,T) of a slice &[T]
pub fn minmaxt<T>(v:&[T]) -> (T,T) where T:PartialOrd+Copy;

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

/// Finds min and max of a subset of v, defined by its subslice between i,i+n.
pub fn minmax_slice<T>(v:&[T], i:usize, n:usize) -> MinMax<T>
where T: PartialOrd + Copy;

/// Using only a subset of v, defined by its idx subslice between i,i+n.
/// Returns min of v, its index's index, max of v, its index's index.
pub fn minmax_indexed<T>(v:&[T], idx:&[usize], i:usize, n:usize) -> MinMax<T>
where T: PartialOrd + Copy;

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

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

/// Finds the first occurrence 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;

/// Counts occurrences of val by simple linear search of any unordered set
pub fn occurs<T>(set: &[T], val:T) -> usize where T: PartialOrd+Copy;

/// Counts occurrences of val by binary search, using previously obtained sorts.
pub fn occurs_multiple<T>(sasc: &[T], sdesc: &[T], val: T) -> usize  
where T: PartialOrd+Copy;

/// 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;

/// Partition with respect to a pivot into three sets
pub fn partition<T>(v: &[T], pivot:T) -> (Vec<T>, Vec<T>, Vec<T>)
where T: PartialOrd+Copy;

/// Partition about pivot into three sets of indices (lt,eq,gt)
pub fn partition_indexed<T>(v: &[T], pivot: T) -> (Vec<usize>, Vec<usize>, Vec<usize>)  
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;

/// N recursive non-destructive hash sort: min,max, is the data range.
pub fn hashsort_indexed<T>(s: &[T], min:f64, max:f64) -> Vec<usize>;

/// N recursive hash sort: min,max, is the data range. Explicitly sorts s in-place.
pub fn hashsort<T>(s: &mut[T], min:f64, max:f64); 

Release Notes (Latest First)

Version 1.1.7 - Added method wvec(self,&mut f). It writes vectors to file f and passes up errors. Added colour blue(). Added printing test. Prettier readme.md.

Version 1.1.6 - Added simple partition into three sets (lt,eq,gt).

Version 1.1.5 - Updated dev dependency to ran = "^0.3". Changed partition_indexed to include equal set. Tweaked printing layout.

Version 1.1.4 - Minor change: hashsort min,max arguments type changed from T to f64. This is more convenient for apriori known data range limits. Also to be the same as for hashsort_indexed. Added newindex and minmax_slice functions. Updated readme file.

Version 1.1.3 - hashsort renamed to hashsort_indexed, in keeping with the naming convention here. New plain hashsort added: it sorts &mut[T] in place, just like does the default Rust sort. Suitable for long explicit sorts.

Version 1.1.2 - Added .red() method to Printing. Some tidying up of tests.rs and the docs. hashsort improved.

Version 1.1.0 - Added superfast n-recursive hashsort. Suitable for multithreading (todo).

Version 1.0.9 - Minor changes to testing.rs to better test ran.

Version 1.0.8 - Dependencies reorganization to minimise the footprint. The random numbers generation has now been moved to its own new crate ran and added here just as a development dependency where it rightfully belongs.

Version 1.0.7 - Renamed function occurs to occurs_multiple and added a simple linear count of item occurences: occurs.

Version 1.0.6 - Some cosmetic changes to the code, readme and tests, no change of functionality.

Version 1.0.5 - Added partition_indexed for partitioning into two sets of indices about a pivot. Moved all random number generating functions into new module random.rs (import changed to: random::*). Moved the implementations of Printing trait to new module printing.rs (this has no effect on users).

Version 1.0.4 - here!() now highlights the (first) error in bold red. Added fast random number generation functions ranf64, ranv64, ranvu8, ranvvf64, rannvvu8.

Version 1.0.3 - Added utilities functions maxt, mint, minmaxt. Rationalised the functions for printing generic slices and slices of vectors. They are now turned into two chainable methods in trait Printing: .to_str() and .gr(). The latter also serialises slices to strings but additionally makes them bold green.

Version 1.0.2 - Added function occurs that efficiently counts occurrences of specified items in a set with repetitions.

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.