Indxvec
Vecs indexing, ranking, sorting, merging, searching, reversing, intersecting, printing, etc.
The following will import everything
use ;
Description
This crate is lightweight and has no dependencies. The methods of all four traits can be functionally chained together to achieve numerous manipulations of vectors and their indices in compact form.
The facilities provided are:
- ranking, sorting (merge sort and hash sort), merging, searching, indexing, selecting, partitioning
- many useful operations on generic vectors and their indices
- set operations
- serialising generic slices and slices of vectors to Strings:
to_plainstr()
- printing generic slices and slices of vectors:
pvec()
- writing generic slices and slices of vectors to files:
wvec(&mut f)
- coloured pretty printing (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. It is also necessary to tun the timing benchmark sorts()
on its own for meaningful results.
Glossary
-
Sort Index - is obtained by stable merge sort
sort_indexed
or byhashsort_indexed
. The original data is immutable (unchanged). The sort index produced is a list of subscripts to the data, such that the first subscript identifies the smallest item in the data, and so on (in ascending order). Suitable for bulky data that are not easily moved. It answers the question: 'what data item occupies a given sort position?'. -
Reversing an index - sort index can be reversed by generic reversal operation
revs()
, ormutrevs()
. This has the effect of changing between ascending/descending sort orders without re-sorting or even reversing the (possibly bulky) actual data. -
Rank Index - corresponds to the given data order, listing the sort positions (ranks) for the data items, e.g.the third entry in the rank index gives the rank of the third data item. Some statistical measures require ranks of data. It answers the question: 'what is the sort position of a given data item?'.
-
Inverting an index - sort index and rank index are mutually inverse. Thus they can be easily switched by
invindex()
. This is usually the easiest way to obtain a rank index. They will both be equal to0..n
for data that is already in ascending order. -
Complement of an index - beware that the standard reversal will not convert directly between ascending and descending ranks. This purpose is served by
complindex()
. Alternatively, descending ranks can be reconstructed by applyinginvindex()
to a descending sort index. -
Unindexing - given a sort index and some data,
unindex()
will pick the data in the new order defined by the sort index. It can be used to efficiently transform lots of data vectors into the same (fixed) order. For example: Suppose we have vectors:keys
anddata_1,..data_n
, not explicitly joined together in some bulky Struct elements. The sort index obtained by:let indx = keys.sort_indexed()
can then be efficiently applied to sort the data vectors individually, e.g.indx.unindex(data_n,true)
(false to obtain a descending order at no extra cost).
Trait Indices
use ;
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 Vec<f64>
, or other results, as appropriate. Please see the Glossary below for descriptions of the indices and operations on them.
/// Methods to manipulate indices of `Vec<usize>` type.
Trait Vecops
use ;
The methods of this trait are applicable to all generic slices &[T]
(the data). Thus they will work on all Rust primitive numeric end types, such as f64. They can also work on slices holding any arbitrarily complex end type T
, as long as the required traits, PartialOrd
and/or Copy
, are implemented for T
.
Trait Mutops
use ;
This trait contains muthashsort
, which overwrites self
with sorted data. When we do not need to keep the original order, this is the most efficient way to sort.
Nota bene: muthashsort
really wins on longer Vecs. For about one thousand items upwards, it is on average about 25%-30% faster than the default Rust (Quicksort) sort_unstable
.
/// Mutable Operators on `&mut[T]`
Trait Printing
use Printing; // the trait methods
use *; // the colour constants
This trait provides utility methods to 'stringify' (serialise) generic slices and slices of Vec
s. 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.
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: .to_plainstr
, .to_str()
, .gr()
, .rd()
, .yl()
.bl()
, .mg()
, .cy()
convert all these types to printable strings. The colouring methods just add the relevant colouring to the formatted output of .to_str()
.
fn wvec(self,f:&mut File) -> Result<(), io::Error> where Self: Sized;
writes plain space separated values (.ssv
) 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 use them in any formatting strings manually. For example,
switching colours:
use *; // ANSI colours constants
println!;
Note that all of these methods and interpolations set their own new 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 the colouring methods rd()..cy()
. 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.
Example from tests/tests.rs
:
println!;
memsearch
returns Option(None)
, when midval
is not found in vm
. Here, None
will be printed in red, while any found item will be printed in green. This is also an example of how to process Option
s without the long-winded match
statements.
Structs and Utility Functions
use ;
pub struct Found
for general result of binary search. Index and count of items found.pub struct Minmax
holds minimum and maximum values of aVec
and their indices.pub struct F64(pub f64)
is a wrapper for custom conversions of T to f64, needed by hashsort for non-numeric types.pub fn inf64<T>(arg:T) -> f64 where F64:From<T>
is a utility that converts generic T type value to f64.here!()
is a macro giving the filename, line number and function name of the place from where it was invoked. It can be interpolated into any error/tracing messages and reports.
Release Notes (Latest First)
Version 1.3.1 - Binary search methods now return standard rust type Range.
Version 1.3.0 - Binary search that is superior to std:slice:binary_search
. Two methods provided: binsearch
and binsearch_indexed
. Removed spurious newline from printing matrices. Updated times
dependency.
Version 1.2.13 - Removed no longer needed unindexf64
from trait Indices
.
Version 1.2.12 - Improved some sort algorithms. Removed dev-dependence devtimer
and updated other dependencies. Note that the sorts()
benchmarking test needs to be run on its own. When run under cargo test -- --nocapture
, together with all the other tests, its timings are unreliable.
Version 1.2.11 - Moved the benchmark timing function to its own new crate called times
.
Version 1.2.10 - Moved tof64
into Vecops
trait to act as one of its methods: v.tof64()
. Added default Rust destructive sort mutsort
to trait Mutops
. Added benchmarking function sorts()
into tests.rs
. It also illustrates effective use of an index sort.
Version 1.2.9 - Added explicit conversion from f64 to f64, without which the methods needing F64:From<T>
did not do work when T=f64. The primitive numeric types up to u64, i64, f64 varieties now all work, plus the custom lexical quantification of &str. It should be easy to add more custom ones. All this achieved without resorting to unstable specialization
feature.
Version 1.2.8 - Enabled custom conversions of non-numeric end types, specifically &str. This is so that hashsort
can compute its keys and sort them. Thus widening the applicability of superfast hashsort.
Version 1.2.6 - Renamed trait Mutsort
to Mutops
. Renamed some Vecops
methods for naming consistency. Made hashsort easier to use by removing the data range. Added sorth
, equivalent to sortm
, using hashsort instead of mergesort. Added a test.
Version 1.2.5 - Removed revindex()
as its effect was a duplication of generic revs()
. Added mutable version mutrevs()
.
Version 1.2.4 - Clarified some comments and indxvec
test in tests/tests.rs
.
Version 1.2.3 - Added binsearch_indexed
and binsearchdesc_indexed
and their tests, for symmetry with memsearch
versions which only search for members, whereas binsearch
finds order positions for non-members, too.
Version 1.2.2 - Minor test clarification. Expanded the glossary.
Version 1.2.1 - Removed the functions module merge.rs
, it has been replaced by traits Vecops
and Mutsort
. Improved hashsorts. Added some more comments. Added short glossary.
Version 1.2.0 - Changed functions in module merge.rs
to trait methods in two new traits: Vecops
and Mutsort
. Applying trait methods is more idiomatic and easier to read when chained. Narrowed down some trait constraints. Kept the old functions for now for backwards compatibility but they will be removed in the next version to save space.