Indxvec

Description

The following will import everything:

use indxvec::{MinMax,here,tof64,printing::*,merge::*,Indices,Printing};

This crate is lightweight and has no dependencies.

The facilities provided are:

• ranking, sorting, merging, searching, indexing, selecting, partitioning
• general operations on vectors and their indices
• set operations
• serialising generic slices and slices of vectors to Strings: to_str()
• printing generic slices and slices of vectors: pvec()
• writing generic slices and slices of vectors to files: wvec(&mut f)
• coloured ANSI terminal output (mainly for testing)
• macro here!() for more informative errors reporting

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

Struct and helper functions

use indxvec::{MinMax,here,tof64};

Struct Minmax holds minimum and maximum values of a Vec and their indices.
here!() is a macro for more informative error reports.
pub fn tof64<T>(s: &[T]) -> Vec<f64>... converts generic Vecs end types to f64s.

Trait Indices

use indxvec::{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

use indxvec::Printing;    // the trait methods

This trait provides utility methods to stringify (serialise) generic slices and slices of vecs. Also, methods for writing or printing them. Optionally, it enables printing them in bold ANSI terminal colours for adding emphasis. See tests/tests.rs for examples of usage.

pub trait Printing<T> {

    /// Methods to serialize and render the resulting string
    /// in bold ANSI terminal colours.
    fn rd(self) -> String where Self: Sized { 
        format!("{RD}[{}]{UN}",self.to_str()) }
    fn gr(self) -> String where Self: Sized { 
        format!("{GR}[{}]{UN}",self.to_str()) }
    fn yl(self) -> String where Self: Sized { 
        format!("{YL}[{}]{UN}",self.to_str()) }    
    fn bl(self) -> String where Self: Sized { 
        format!("{BL}[{}]{UN}",self.to_str()) }
    fn mg(self) -> String where Self: Sized { 
        format!("{MG}[{}]{UN}",self.to_str()) }
    fn cy(self) -> String where Self: Sized { 
        format!("{CY}[{}]{UN}",self.to_str()) }        

    /// Method to write vector(s) to file f. Passes up io errors
    fn wvec(self,f:&mut File) -> Result<(), io::Error> where Self: Sized { 
        Ok(write!(*f,"{} ", self.to_str())?) 
    }

    /// Method to print vector(s) to stdout.
    fn pvec(self) where Self: Sized { 
        print!("{} ", 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;
}

The methods of this trait are implemented for generic individual items T, for slices &[T] for slices of slices &[&[T]] and for slices of vecs &[Vec<T>]. Note that these types are normally unprintable in Rust (do not have Display implemented).

The following methods of this trait: .to_str(), .gr(), .rd(), .yl() .bl(), .mg(), .cy() convert all these types to printable strings. The colouring methods just add the relevant colour encodings and pretty-printing to the plain output of .to_str().

fn wvec(self,f:&mut File) -> Result<(), io::Error> where Self: Sized;
is used to write plain space separated values (.ssv) output to files, possibly raising io::Error(s).

fn pvec(self) where Self: Sized;
prints to stdout.

For finer control of the colouring, import the colour constants from module printing and then use them in any formatting strings manually. For example, switching colours:

use indxvec::printing::*; // ANSI colours constants
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 colouring methods .gr(), etc. Be careful to always close with one of these, or explicit {UN}, otherwise all the following output will continue with the last selected colour foreground rendering.

String objects should not have .to_str() called on them, as it is not needed. Such application will not fail but since String is a Vec of characters, the colouring functions will add their pretty printing 'list' brackets around it, which is probably not wanted. Thus it is better to bracket existing Strings manually, for example:

println!("Memsearch for {BL}{midval}{UN}, found at: {}",
    memsearch(&vm, &vi,midval)
        .map_or_else(||format!("{RD}None{UN}"),|x| x.gr())
);

Here memsearch returns Option: None, when midval (printed in blue) is not found. None will be printed in red, while any found item will be green (without long-winded match statements).

Functions in module merge.rs

use indxvec::{merge::*};

These functions are mostly 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.

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 Quicksort.

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 1.1.8 - Added method pvec(self) to Printing trait. It prints vecs to stdout. Completed all six ANSI terminal primary bold colours. Moved their constants to module printing.rs. Renamed red() to rd() for consistent two letter names. Updated and reorganised readme.

Version 1.1.7 - Added method wvec(self,&mut f) to Printing. It writes vectors to file f and passes up errors. Added colour bl(). 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.