Julia v0.4.0 Release Notes

New language features

Function call overloading: for arbitrary objects x (not of type Function), x(...) is transformed into call(x, ...), and call can be overloaded as desired. Constructors are now a special case of this mechanism, which allows e.g. constructors for abstract types. T(...) falls back to convert(T, x), so all convert methods implicitly define a constructor (#8712, #2403).
Unicode version 8 is now supported for identifiers etcetera (#7917, #12031).
Type parameters now permit any isbits type, not just Int and Bool (#6081).
Keyword argument names can be computed, using syntax such as f(; symbol => val) (#7704).
The syntax @generated function enables generation of specialized methods based on argument types. At compile time, the function is called with its arguments bound to their types instead of to their values. The function then returns an expression forming the body of the function to be called at run time (#7311).
Documentation system for functions, methods, types and macros in packages and user code (#8791).
The syntax function foo end can be used to introduce a generic function without yet adding any methods (#8283).
Incremental precompilation of modules: call VERSION >= v"0.4.0-dev+6521" && __precompile__() at the top of a module file to automatically precompile it when it is imported (#12491), or manually run Base.compilecache(modulename). The resulting precompiled .ji file is saved in ~/.julia/lib/v0.4 (#8745).
- See manual section on Module initialization and precompilation (under Modules) for details and errata. In particular, to be safely precompilable a module may need an __init__ function to separate code that must be executed at runtime rather than precompile time. Modules that are not precompilable should call __precompile__(false).
- The precompiled .ji file includes a list of dependencies (modules and files that were imported/included at precompile-time), and the module is automatically recompiled upon import when any of its dependencies have changed. Explicit dependencies on other files can be declared with include_dependency(path) (#12458).
- New option --output-incremental={yes|no} added to invoke the equivalent of Base.compilecache from the command line.
The syntax new{parameters...}(...) can be used in constructors to specify parameters for the type to be constructed (#8135).
++ is now parsed as an infix operator, but does not yet have a default definition (#11030, #11686).
Support for inter-task communication using Channels (#12264). See http://docs.julialang.org/en/latest/manual/parallel-computing/#channels for details.
RemoteRefs now point to remote channels. The remote channels can be of length greater than 1. Default continues to be of length 1 (#12385). See http://docs.julialang.org/en/latest/manual/parallel-computing/#remoterefs-and-abstractchannels for details.
@__LINE__ special macro now available to reflect invocation source line number (#12727).

Language changes

Tuple types are now written as Tuple{A, B} instead of as (A, B). Tuples of bits types are inlined into structs and arrays, like other immutable types. ... now does splatting inside parentheses, instead of constructing a variadic tuple type (#10380). Variadic tuple types are written as Tuple{Vararg{T}}.
Using [x,y] to concatenate arrays is deprecated, and in the future will construct a vector of x and y instead (#3737, #2488, #8599).
Significant improvements to ccall and cfunction
- As a safer alternative to creating pointers (Ptr), the managed reference type Ref has been added. A Ref points to the data contained by a value in an abstract sense, and in a way that is GC-safe. For example, Ref(2) points to a storage location that contains the integer 2, and Ref(array,3) points to the third element of an array. A Ref can be automatically converted to a native pointer when passed to a ccall.
- When passing a by-reference argument to ccall, you can declare the argument type to be Ref{T} instead of Ptr{T}, and just pass x instead of &x.
- ccall is now lowered to call unsafe_convert(T, cconvert(T, x)) on each argument. cconvert falls back to convert, but can be used to convert an argument to an arbitrarily-different representation more suitable for passing to C. unsafe_convert then handles conversions to Ptr.
- ccall and cfunction now support correctly passing and returning structs, following the platform ABI (assuming the C types are mirrored accurately in Julia).
- cfunction arguments of struct-like Julia types are now passed by value. If Ref{T} is used as a cfunction argument type, it will look up the method applicable to T, but pass the argument by reference (as Julia functions usually do). However, this should only be used for objects allocated by Julia and for isbits types.
convert(Ptr,x) is deprecated for most types, replaced by unsafe_convert. You can still convert between pointer types, and between pointers and Int or UInt.
Module __init__ methods no longer swallow thrown exceptions; they now throw an InitError wrapping the thrown exception (#12576).
Unsigned BigInt literal syntax has been removed (#11105). Unsigned literals larger than UInt128 now throw a syntax error.
error(::Exception) and error(::Type{Exception}) have been deprecated in favor of using an explicit throw (#9690).
Uint etcetera are renamed to UInt (#8905).
String is renamed to AbstractString (#8872).
FloatingPoint is renamed to AbstractFloat (#12162).
None is deprecated; use Union{} instead (#8423).
Nothing (the type of nothing) is renamed to Void (#8423).
Arrays can be constructed with the syntax Array{T}(m,n) (#3214, #10075).
Dict literal syntax [a=>b,c=>d] is replaced by Dict(a=>b,c=>d), {a=>b} is replaced by Dict{Any,Any}(a=>b), and (K=>V)[...] is replaced by Dict{K,V}(...). The new syntax has many advantages: all of its components are first-class, it generalizes to other types of containers, it is easier to guess how to specify key and value types, and the syntaxes for empty and pre-populated dicts are synchronized. As part of this change, => is parsed as a normal operator, and Base defines it to construct Pair objects (#6739).
Char is no longer a subtype of Integer (#8816). Char now supports a more limited set of operations with Integer types:
- comparison / equality
- Char + Int = Char
- Char - Char = Int
round rounds to the nearest integer using the default rounding mode, which is ties-to-even by default (#8750).
A custom triple-quoted string like x"""...""" no longer invokes an x_mstr macro. Instead, the string is first unindented and then x_str is invoked, as if the string had been single-quoted (#10228).
Colons (:) within indexing expressions are no longer lowered to the range 1:end. Instead, the : identifier is passed directly. Custom array types that implement getindex or setindex! methods must also extend those methods to support arguments of type Colon (#10331).
Unions of types should now be written with curly braces instead of parentheses, i.e. Union{Type1, Type2} instead of Union(Type1, Type2) (#11432).
The keyword local is no longer allowed in global scope. Use let instead of begin to create a new scope from the top level (#7234, #10472).
Triple-quoted strings no longer treat tabs as 8 spaces. Instead, the longest common prefix of spaces and tabs is removed.
global x in a nested scope is now a syntax error if x is local to the enclosing scope (#7264/#11985).
The default importall Base.Operators is deprecated, and relying on it will give a warning (#8113).
remotecall_fetch and fetch now rethrow any uncaught remote exception locally as a RemoteException. Previously they would return the remote exception object. The worker pid, remote exception and remote backtrace are available in the thrown RemoteException.
If any of the enclosed async operations in a @sync block throw exceptions, they are now collected in a CompositeException and the CompositeException thrown.

Command line option changes

The -i option now forces the REPL to run after loading the specified script (if any) (#11347).
New option --handle-signals={yes|no} to disable Julia's signal handlers.
The --depwarn={yes|no|error} option enables/disables syntax and method deprecation warnings, or turns them into errors (#9294).
Some command line options are slated for deprecation / removal
- -f, --no-startup Don't load ~/.juliarc (deprecated, use --startup-file=no)
- -F Load ~/.juliarc (deprecated, use --startup-file=yes)`
- -P, --post-boot <expr> Evaluate , but don't disable interactive mode (deprecated, use -i -e instead)
- --no-history-file Don't load history file (deprecated, use --history-file=no)

Compiler/Runtime improvements

Functions may be annotated with metadata (:meta expressions) to be used by the compiler (#8297).
@inline before a function definition forces the compiler to inline the function (#8297).
Loads from heap-allocated immutables are hoisted out of loops in more cases (#8867).
Accessing fields that are always initialized no longer produces undefined checks (#8827).
New generational garbage collector which greatly reduces GC overhead for many commmon workloads (#5227).

Library improvements

Build with USE_GPL_LIBS=0 to exclude all GPL libraries and code (#10870).
Linear algebra
- The LinAlg module is now exported.
- sparse(A) now takes any AbstractMatrix A as an argument (#10031).
- Factorization API is now type-stable; functions dispatch on Val{false} or Val{true} instead of a boolean value (#9575).
- Added generic Cholesky factorization, and the Cholesky factorization is now parametrized by the matrix type (#7236).
- Sparse cholfact and ldltfact functions now accept a perm keyword for user-provided permutations and a shift keyword to factorize a shifted matrix (#10844).
- New svds function for the sparse truncated SVD (#9425).
- Symmetric and Hermitian immutables are now parametrized by the matrix type (#7992).
- New ordschur and ordschur! functions for sorting a Schur factorization by the eigenvalues (#8467,#9701).
- Givens type doesn't have a size anymore and is no longer a subtype of AbstractMatrix (#8660).
- Large speedup in sparse \ and splitting of Cholesky and LDLᵀ factorizations into cholfact and ldltfact (#10117).
- Add sparse least squares to \ by adding qrfact for sparse matrices based on the SPQR library (#10180).
- Split Triangular type into UpperTriangular, LowerTriangular, UnitUpperTriagular and UnitLowerTriangular (#9779)
- OpenBLAS 64-bit (ILP64) interface is now compiled with a 64_ suffix (#8734) to avoid conflicts with external libraries using a 32-bit BLAS (#4923).
- New vecdot function, analogous to vecnorm, for Euclidean inner products over any iterable container (#11067).
- p = plan_fft(x) and similar functions now return a Base.DFT.Plan object, rather than an anonymous function. Calling it via p(x) is deprecated in favor of p * x or p \ x (for the inverse), and it can also be used with A_mul_B! to employ pre-allocated output arrays (#12087).
- LU{T,Tridiagonal{T}} now supports extraction of L, U, p, and P factors (#12137).
- Allocations in sparse matrix factorizations are now tracked by Julia's garbage collector (#12034).
Strings
- NUL-terminated strings should now be passed to C via the new Cstring type, not Ptr{UInt8} or Ptr{Cchar}, in order to check whether the string is free of NUL characters (which would cause silent truncation in C). The analogous type Cwstring should be used for NUL-terminated wchar_t* strings (#10994).
- graphemes(s) returns an iterator over grapheme substrings of s (#9261).
- Character predicates such as islower(), isspace(), etc. use utf8proc to provide uniform cross-platform behavior and up-to-date, locale-independent support for Unicode standards (#5939).
- reverseind function to convert indices in reversed strings (e.g. from reversed regex searches) to indices in the original string (#9249).
- charwidth(c) and strwidth(s) now return up-to-date cross-platform results (via utf8proc) (#10659): Julia now likes pizza (#3721), but some terminals still don't.
- is_valid_char(c), (now isvalid(Char,c) (#11241)), now correctly handles Unicode "non-characters", which are valid Unicode codepoints (#11171).
- Backreferences in replacement strings in calls to replace with a Regex pattern are now supported (#11849). Use the s string prefix to indicate a replacement string contains a backreference. For example, replace("ab", r"(.)(.)", s"\2\1") yields "ba".
- Capture groups in regular expressions can now be named using PCRE syntax, (?P<group_name>...). Capture group matches can be accessed by name by indexing a Match object with the name of the group (#11566).
- countlines() now counts all lines, not just non-empty (#11947).
Array and AbstractArray improvements
- New multidimensional iterators and index types for efficient iteration over AbstractArrays. Array iteration should generally be written as for i in eachindex(A) ... end rather than for i = 1:length(A) ... end (#8432).
- New implementation of SubArrays with substantial performance and functionality improvements (#8501).
- AbstractArray subtypes only need to implement size and getindex for scalar indices to support indexing; all other indexing behaviors (including logical indexing, ranges of indices, vectors, colons, etc.) are implemented in default fallbacks. Similarly, they only need to implement scalar setindex! to support all forms of indexed assingment (#10525).
- AbstractArrays that do not extend similar now return an Array by default (#10525).
Data structures
- New sortperm! function for pre-allocated index arrays (#8792).
- Switch from O(N) to O(log N) algorithm for dequeue!(pq, key) with PriorityQueue. This provides major speedups for large queues (#8011).
- PriorityQueue now includes the order type among its parameters, PriorityQueue{KeyType,ValueType,OrderType}. An empty queue can be constructed as pq = PriorityQueue(KeyType,ValueType), if you intend to use the default Forward order, or pq = PriorityQueue(KeyType, ValueType, OrderType) otherwise (#8011).
- Efficient mean and median for ranges (#8089).
- deepcopy recurses through immutable types and makes copies of their mutable fields (#8560).
- copy(a::DArray) will now make a copy of a DArray (#9745).
New types
- Enums are now supported through the @enum EnumName EnumValue1 EnumValue2 syntax. Enum member values also support abitrary value assignment by the @enum EnumName EnumValue1=1 EnumValue2=10 EnumValue3=20 syntax (#10168).
- New Dates module for calendar dates and other time-interval calculations (#7654).
- New Nullable type for missing data (#8152).
- A new Val{T} type allows one to dispatch on bits-type values (#9452).
- linspace now returns a LinSpace object which lazily computes linear interpolation of values between the start and stop values. It "lifts" endpoints which are approximately rational in the same manner as the colon operator.
Arithmetic
- convert now checks for overflow when truncating integers or converting between signed and unsigned (#5413).
- Arithmetic is type-preserving for more types; e.g. (x::Int8) + (y::Int8) now yields an Int8 (#3759).
- Reductions (e.g. reduce, sum) widen small types (integers smaller than Int, and Float16).
- Added optional rounding argument to floating-point constructors (#8845).
- Equality (==) and inequality (</<=) comparisons are now correct across all numeric types (#9133, #9198).
- Rational arithmetic throws errors on overflow (#8672).
- Optional log and log1p functions implemented in pure Julia (experimental) (#10008).
- The MathConst type has been renamed Irrational (#11922).
- isapprox now has simpler and more sensible default tolerances (#12393), supports arrays, and has synonyms ≈ (U+2248, LaTeX \approx) and ≉ (U+2249, LaTeX \napprox) for isapprox and !isapprox, respectively (#12472).
Numbers
- primes is now faster and has been extended to generate the primes in a user defined closed interval (#12025).
- The function primesmask which generates a prime sieve for a user defined closed interval is now exported (#12025).
Random numbers
- Streamlined random number generation APIs #8246. The default rand no longer uses global state in the underlying C library, dSFMT, making it closer to being thread-safe (#8399, #8832). All APIs can now take an AbstractRNG argument (#8854, #9065). The seed argument to srand is now optional (#8320, #8854). The APIs accepting a range argument are extended to accept an arbitrary AbstractArray (#9049). Passing a range of BigInt to rand or rand! is now supported (#9122). There are speed improvements across the board (#8808, #8941, #8958, #9083).
- Significantly faster randn (#9126, #9132).
- The randexp and randexp! functions are exported (#9144).
File
- Added function readlink which returns the value of a symbolic link "path" (#10714).
- Added function ismount which checks if a directory is a mount point (#11279).
- The cp function now accepts keyword arguments remove_destination and follow_symlinks (#10888).
- The mv function now accepts keyword argument remove_destination (#11145).
Pipe() creates a bidirectional I/O object that can be passed to spawn or pipeline for redirecting process streams (#12739).
Other improvements
- You can now tab-complete Emoji characters via their short names, using \:name:<tab> (#10709).
- gc_enable subsumes gc_disable, and also returns the previous GC state.
- assert, @assert now throws an AssertionError exception type (#9734).
- @simd now rejects invalid control flow (@goto / break / continue) in the inner loop body at compile time (#8624).
- The machinefile now supports a host count (#7616).
- code_native now outputs branch labels (#8897).
- Added recvfrom to get source address of UDP packets (#9418).
- ClusterManager performance improvements (#9309) and support for changing transports(#9434).
- Added Base.get_process_title / Base.set_process_title (#9957).
- readavailable now returns a byte vector instead of a string.
- New lock and unlock functions, operating on ReentrantLock, to lock a stream during concurrent writes from multiple tasks (#10679).
- code_llvm now outputs stripped IR without debug info or other attached metadata. Use code_llvm_raw for the unstripped output (#10747).
- New withenv(var=>val, ...) do ... end function to temporarily modify environment variables (#10914).
- New function relpath returns a relative filepath to path either from the current directory or from an optional start directory (#10893).
- mktemp and mktempdir now take an optional argument to set which directory the temporary file or directory is created in.
- New garbage collector tracked memory allocator functions: jl_malloc, jl_calloc, jl_realloc, and jl_free with libc API ([#12034]).
- mktempdir and mktemp now have variants that take a function as its first argument for automated clean-up ([#9017]).

Deprecated or removed

several syntax whitespace insensitivities have been deprecated (#11891).

 # function call
 f (x)

 # getindex
 x [17]
 rand(2) [1]

 # function definition
 f (x) = x^2
 function foo (x)
x^2
 end

indexing with Reals that are not subtypes of Integers (Rationals, AbstractFloat, etc.) has been deprecated (#10458).
push!(A) has been deprecated, use append! instead of splatting arguments to push! (#10400).
names for composite datatypes has been deprecated and renamed to fieldnames (#10332).
DArray functionality has been removed from Base and is now a standalone package under the JuliaParallel umbrella organization (#10333).
The Graphics module has been removed from Base and is now a standalone package (#10150, #9862).
The Woodbury special matrix type has been removed from LinAlg (#10024).
median and median! no longer accept a checknan keyword argument (#8605).
inf and nan are now deprecated in favor of T(Inf) and T(NaN), respectively (#8776).
oftype(T::Type, x) is deprecated in favor of convert(T,x) (or T(x)).
{...} syntax is deprecated in favor of Any[...] (#8578).
itrunc, ifloor, iceil and iround are deprecated in favour of trunc{T<:Integer}(T,x), floor{T<:Integer}(T,x), etc.. trunc is now always bound-checked;Base.unsafe_trunc provides the old unchecked itrunc behaviour (#9133).
squeeze now requires that passed dimension(s) are an Int or tuple of Ints; calling squeeze with an arbitrary iterator is deprecated (#9271). Additionally, passed dimensions must be unique and correspond to extant dimensions of the input array.
randbool is deprecated. Use rand(Bool) to produce a random boolean value, and bitrand to produce a random BitArray (#9105, #9569).
beginswith is renamed to startswith (#9578).
null is renamed to nullspace (#9714).
The operators |>, .>, >>, and .>> as used for process I/O redirection are replaced with the pipeline function (#5349, #12739).
flipud(A) and fliplr(A) have been deprecated in favor of flipdim(A, 1) and flipdim(A, 2), respectively (#10446).
Numeric conversion functions whose names are lower-case versions of type names have been removed. To convert a scalar, use the type name, e.g. Int32(x). To convert an array to a different element type, use Array{T}(x), map(T,x), or round(T,x). To parse a string as an integer or floating-point number, use parse (#1470, #6211).
Low-level functions from the C library and dynamic linker have been moved to modules Libc and Libdl, respectively (#10328).
The functions parseint, parsefloat, float32_isvalid, float64_isvalid, and the string-argument BigInt and BigFloat have been replaced by parse and tryparse with a type argument. The string macro big"xx" can be used to construct BigInt and BigFloat literals (#3631, #5704, #9487, #10543, #10955).
the --int-literals compiler option is no longer accepted (#9597).
Instead of linrange, use linspace (#9666).
The functions is_valid_char, is_valid_ascii, is_valid_utf8, is_valid_utf16, and is_valid_utf32 have been replaced by generic isvalid methods. The single argument form isvalid(value) can now be used for values of type Char, ASCIIString, UTF8String, UTF16String and UTF32String. The two argument form isvalid(type, value) can be used with the above types, with values of type Vector{UInt8}, Vector{UInt16}, Vector{UInt32}, and Vector{Char} (#11241).
Instead of utf32(64,123,...) use utf32(UInt32[64,123,...]) (#11379).
start_timer and stop_timer are replaced by Timer and close.
The following internal julia C functions have been renamed, in order to prevent potential naming conflicts with C libraries: (#11741)
- gc_wb* -> jl_gc_wb*
- gc_queue_root -> jl_gc_queue_root
- allocobj -> jl_gc_allocobj
- alloc_[0-3]w -> jl_gc_alloc_*w
- diff_gc_total_bytes -> jl_gc_diff_total_bytes
- sync_gc_total_bytes -> jl_gc_sync_total_bytes
require(::AbstractString) and reload (see news about addition of compile).
cartesianmap is deprecated in favor of iterating over a CartesianRange

Julia v0.3.0 Release Notes

New language features

Greatly enhanced performance for passing and returning Tuples (#4042).
Tuples (of Integers, Symbols, or Bools) can now be used as type parameters (#5164).
An additional default "inner" constructor accepting any arguments is now generated. Constructors that look like MyType(a, b) = new(a, b) do not need to be added manually (#4026, #7071).
Expanded array type hierarchy to include an abstract DenseArray for in-memory arrays with standard strided storage (#987, #2345, #6212).
When reloading code, types whose definitions have not changed can be ignored in some cases.
Binary ~ now parses as a vararg macro call to @~. For example x~y~z => @~ x y z (#4882).
Structure fields can now be accessed by index (#4806).
If a module contains a function __init__(), it will be called when the module is first loaded, and on process startup if a pre-compiled version of the module is present (#1268).
Multi-line comments (#69, #6128): #= .... =#
--check-bounds=yes|no compiler option
Unicode identifiers are normalized (NFC) so that different encodings of equivalent strings are treated as the same identifier (#5462).
The set of characters permitted in identifiers has been restricted based on Unicode categories. Generally, punctuation, formatting and control characters, and operator symbols are not allowed in identifiers. Number-like characters cannot begin identifiers (#5936).

Define a limited number of infix Unicode operators (#552, #6582):

Precedence class	Operators (with synonyms, if any)
==	≥ (>=) ≤ (<=) ≡ (===) ≠ (!=) ≢ (!==) .≥ (.>=) .≤ (.<=) .!= (.≠) ∈ (`in`) ∉ (`(x,y)->!in(x, y)`) ∋ (`(x,y)->in(y, x)`) ∌ (`(x,y)->!in(y, x)`) ⊆ (`issubset`) ⊈ (`(x,y)->!issubset(x, y)`) ⊊ (`(x,y)->x⊆y && x!=y`)
+	∪ (`union`)
*	÷ (`div`) ⋅ (`dot`) × (`cross`) ∩ (`intersect`)
unary	√ ∛

In addition to these, many of the Unicode operator symbols are parsed as infix operators and are available for user-defined methods (#6929).

Improved reporting of syntax errors (#6179)
break inside a for loop with multiple ranges now exits the entire loop nest (#5154)
Local goto statements using the @goto and @label macros (#101).

REPL improvements

New native-Julia REPL implementation, eliminating many problems stemming from the old GNU Readline-based REPL (#6270).
Tab-substitution of LaTeX math symbols (e.g. \alpha by α) (#6911). This also works in IJulia and in Emacs (#6920).
workspace() function for obtaining a fresh workspace (#1195).

Library improvements

isequal now compares all numbers by value, ignoring type (#6624).
Implement limited shared-memory parallelism with SharedArrays (#5380).
Well-behaved floating-point ranges (#2333, #5636). Introduced the FloatRange type for floating-point ranges with a step, which will give intuitive/correct results for classically problematic ranges like 0.1:0.1:0.3, 0.0:0.7:2.1 or 1.0:1/49:27.0.
mod2pi function (#4799, #4862).
New functions minmax and extrema (#5275).
New macros @edit, @less, @code_typed, @code_lowered, @code_llvm and @code_native that all function like @which (#5832).
consume(p) extended to consume(p, args...), allowing it to optionally pass args... back to the producer (#4775).
.juliarc.jl is now loaded for both script and REPL execution (#5076).
The Sys module now includes convenient functions for working with dynamic library handles; Sys.dllist will list out all paths currently loaded via dlopen, and Sys.dlpath will lookup a path from a handle
readdlm treats multiple whitespace characters as a single delimiter by default (when no delimiter is specified). This is useful for reading fixed-width or messy whitespace-delimited data (#5403).
The Airy, Bessel, Hankel, and related functions (airy*, bessel*, hankel*) now detect errors returned by the underlying AMOS library, throwing an AmosException in that case (#4967).
methodswith now returns an array of Methods (#5464) rather than just printing its results.
errno([code]) function to get or set the C library's errno.
GitHub module for interacting with the GitHub API.
Package improvements
- Packages are now installed into .julia/v0.3 by default (or whatever the current Julia version is), so that different versions of Julia can co-exist with incompatible packages. Existing .julia installations are unaffected unless Pkg.init() is run to re-create the package directories (#3344, #5737).
- Pkg.submit(pkg[,commit]) function to automatically submit a GitHub pull request to the package author.
Collections improvements
- Array assignment (e.g. x[:] = y) ignores singleton dimensions and allows the last dimension of one side to match all trailing dimensions of the other (#4048, #4383).
- Dict(kv) constructor for any iterator on (key,value) pairs.
- Multi-key Dicts: D[x,y...] is now a synonym for D[(x,y...)] for associations D (#4870).
- push! and unshift! can push multiple arguments (#4782).
- writedlm and writecsv now accept any iterable collection of iterable rows, in addition to AbstractArray arguments, and the writedlm delimiter can be any printable object (e.g. a String) instead of just a Char.
- isempty now works for any iterable collection (#5827).
- unique now accepts an optional dim argument for finding unique rows or columns of a matrix or regions of a multidimensional array (#5811).
Number improvements
- The ImaginaryUnit type no longer exists. Instead, im is of type Complex{Bool}. Making this work required changing the semantics of boolean multiplication to approximately, true * x = x and false * x = zero(x), which can itself be considered useful (#5468).
- big is now vectorized (#4766)
- nextpow and prevpow now return the a^n values instead of the exponent n (#4819)
- Overflow detection in parseint (#4874).
- rand now supports arbitrary Ranges arguments (#5059).
- expm1 and log1p now support complex arguments (#3141).
- Broadcasting .// is now included (#7094).
- prevfloat and nextfloat now saturate at -Inf and Inf, respectively, and have otherwise been fixed to follow the IEEE-754 standard functions nextDown and nextUp (#5025).
- New function widen for widening numeric types and values, and widemul for multiplying to a larger type (#6169).
- polygamma, digamma, and trigamma now accept complex arguments, and zeta(s, z) now provides the Hurwitz zeta (#7125).
- Narrow integer types (< 32 bits) are promoted to Float64 rather than to Float32 by float(x) (#7390).
String improvements
- Triple-quoted regex strings, r"""...""" (#4934).
- New string type, UTF16String (#4930), constructed by utf16(s) from another string, a Uint16 array or pointer, or a byte array (possibly prefixed by a byte-order marker to indicate endian-ness). Its data is internally NULL-terminated for passing to C (#7016).
- CharString is renamed to UTF32String (#4943), and its data is now internally NULL-terminated for passing to C (#7016). CharString(c::Char...) is deprecated in favor of utf32(c...), and utf32(s) otherwise has functionality similar to utf16(s).
- New WString and wstring synonyms for either UTF16String and utf16 or UTF32String and utf32, respectively, depending on the width of Cwchar_t (#7016).
- normalize_string function to perform Unicode normalization, case-folding, and other transformations (#5576).
- pointer(s, i=1) for ByteString, UTF16String, UTF32String, and SubStrings thereof (#5703).
- bytestring is automatically called on String arguments for conversion to Ptr{Uint8} in ccall (#5677).
Linear algebra improvements
- Balancing options for eigenvector calculations for general matrices (#5428).
- Mutating linear algebra functions no longer promote (#5526).
- condskeel for Skeel condition numbers (#5726).
- norm(::Matrix) no longer calculates a vector norm when the first dimension is one (#5545); it always uses the operator (induced) matrix norm.
- New vecnorm(itr, p=2) function that computes the norm of any iterable collection of numbers as if it were a vector of the same length. This generalizes and replaces normfro (#6057), and norm is now type-stable (#6056).
- New UniformScaling matrix type and identity I constant (#5810).
- None of the concrete matrix factorization types are exported from Base by default anymore.
- Sparse linear algebra
  - 1-d sparse getindex has been implemented (#7047)
  - Faster sparse getindex (#7131).
  - Faster sparse kron (#4958).
  - sparse(A) \ B now supports a matrix B of right-hand sides (#5196).
  - eigs(A, sigma) now uses shift-and-invert for nonzero shifts sigma and inverse iteration for which="SM". If sigma==nothing (the new default), computes ordinary (forward) iterations (#5776).
  - sprand is faster, and whether any entry is nonzero is now determined independently with the specified probability (#6726).
- Dense linear algebra for special matrix types
  - Interconversions between the special matrix types Diagonal, Bidiagonal, SymTridiagonal, Triangular, and Triangular, and Matrix are now allowed for matrices which are representable in both source and destination types (5e3f074b).
  - Allow for addition and subtraction over mixed matrix types, automatically promoting the result to the denser matrix type (a448e080, #5927)
  - new algorithms for linear solvers and eigensystems of Bidiagonal matrices of generic element types (#5277)
  - new algorithms for linear solvers, eigensystems and singular systems of Diagonal matrices of generic element types (#5263)
  - new algorithms for linear solvers and eigensystems of Triangular matrices of generic element types (#5255)
  - specialized inv and det methods for Tridiagonal and SymTridiagonal based on recurrence relations between principal minors (#5358)
  - specialized transpose, ctranspose, istril, istriu methods for Triangular (#5255) and Bidiagonal (#5277)
  - new LAPACK wrappers
    - condition number estimate cond(A::Triangular) (#5255)
  - parametrize Triangular on matrix type (#7064)
  - Lyapunov / Sylvester solver (#7435)
  - eigvals for Symmetric, Tridiagonal and Hermitian matrices now support additional method signatures: (#3688, #6652, #6678, #7647)
    - eigvals(M, el, eu) finds all eigenvalues in the interval (el, eu]
    - eigvals(M, il:iu) finds the ilth through the iuth eigenvalues (in ascending order)
- Dense linear algebra for generic matrix element types
  - LU factorization (#5381 and #5430)
  - QR factorization (#5526)
New function deleteat! deletes a specified index or indices and returns the updated collection
The setenv function for external processes now accepts a dir keyword argument for specifying the directory to start the child process in (#4888).
Constructors for collections (Set, Dict, etc.) now generally accept a single iterable argument giving the elements of the collection (#4996, #4871)
Ranges and arrays with the same elements are now unequal. This allows hashing and comparing ranges to be faster (#5778).
Broadcasting now works on arbitrary AbstractArrays (#5387)
Reduction functions that accept a pre-allocated output array, including sum!, prod!, maximum!, minimum!, all!, any! (#6197, #5387)
Faster performance on fill! and copy! for array types not supporting efficient linear indexing (#5671, #5387)
Changes to range types (#5585)
- Range is now the abstract range type, instead of Ranges
- New function range for constructing ranges by length
- Range is now StepRange, and Range1 is now UnitRange. Their constructors accept end points instead of lengths. Both are subtypes of a new abstract type OrdinalRange.
- Ranges now support BigInt and general ordinal types.
- Very large ranges (e.g. 0:typemax(Int)) can now be constructed, but some operations (e.g. length) will raise an OverflowError.
Extended API for cov and cor, which accept keyword arguments vardim, corrected, and mean (#6273)
New functions randsubseq and randsubseq! to create a random subsequence of an array (#6726)
New macro @evalpoly for efficient inline evaluation of polynomials (#7146).
The signal filtering function filt now accepts an optional initial filter state vector. A new in-place function filt! is also exported (#7513).
Significantly faster cumsum and cumprod (#7359).
Implement findmin and findmax over specified array dimensions (#6716).
Support memory-mapping of files with offsets on Windows (#7242).
Catch writes to protect memory, such as when trying to modify a mmapped file opened in read-only mode (#3434).

Environment improvements

New --code-coverage and --track-allocation startup features allow one to measure the number of executions or the amount of memory allocated, respectively, at each line of code (#5423,#7464).
Profile.init now accepts keyword arguments, and returns the current settings when no arguments are supplied (#7365).

Build improvements

Dependencies are now verified against stored MD5/SHA512 hashes, to ensure that the correct file has been downloaded and was not modified (#6773).

Deprecated or removed

convert(Ptr{T1}, x::Array{T2}) is now deprecated unless T1 == T2 or T1 == Void (#6073). (You can still explicitly convert one pointer type into another if needed.)
Sys.shlib_ext has been renamed to Sys.dlext
dense is deprecated in favor of full (#4759).
The Stat type is renamed StatStruct (#4670).
set_rounding, get_rounding and with_rounding now take an additional argument specifying the floating point type to which they apply. The old behaviour and [get/set/with]_bigfloat_rounding functions are deprecated (#5007).
cholpfact and qrpfact are deprecated in favor of keyword arguments in cholfact(..., pivot=true) and qrfact(..., pivot=true) (#5330).
symmetrize! is deprecated in favor of Base.LinAlg.copytri! (#5427).
myindexes has been renamed to localindexes (#5475).
factorize! is deprecated in favor of factorize (#5526).
nnz counts the number of structural nonzeros in a sparse matrix. Use countnz for the actual number of nonzeros (#6769).
setfield is renamed setfield! (#5748).
put and take are renamed put! and take! (#5511).
put! now returns its first argument, the remote reference (#5819).
read methods that modify a passed array are now called read! (#5970)
infs and nans are deprecated in favor of the more general fill.
* and div are no longer supported for Char.
Range is renamed StepRange and Range1 is renamed UnitRange. Ranges is renamed Range.
bitmix is replaced by a 2-argument form of hash.
readsfrom and writesto are replaced by open (#6948).
insert! now throws a BoundsError if index > length(collection)+1 (#7373).
No longer exported from Base:
- start_reading, stop_reading, start_watching (#10885).

Julia v0.2.0 Release Notes

The 0.2 release brings improvements to many areas of Julia. Among the most visible changes are support for 64-bit Windows, keyword arguments to functions, immutable types, a redesigned and polished package manager, a multimedia interface supporting usage of Julia in IPython, a built-in profiler, and major improvements to Julia's linear algebra, I/O, and parallel capabilities. These are accompanied by many other changes adding new features, enhancing the library's consistency, improving performance, increasing test coverage, easing installation, and expanding the documentation. While not part of Julia proper, the package ecosystem has also grown and matured considerably since the 0.1 release. See below for more information about the long list of changes that improve Julia's usability and performance.

New language features

Keyword & optional function arguments (#485, #1817).
Immutable types (#13).
Triple-quoted string literals (#70).
New infix operator in (e.g. x in S), and corresponding function in(x,S), replacing contains(S,x) function (#2703).

New variable bindings on each for loop and comprehension iteration (#1571). For example, before this change:

julia> map(f->f(), { ()->i for i=1:3 })
3-element Any Array:
 3
 3
 3

and after:

julia> map(f->f(), { ()->i for i=1:3 })
3-element Any Array:
 1
 2
 3

Explicit relative importing (#2375).
Methods can be added to functions in other modules using dot syntax, as in Foo.bar(x) = 0.
import module: name1, name2, ... (#5214).
A semicolon is now allowed after an import or using statement (#4130).

In an interactive session (REPL), you can use ;cmd to run cmd via an interactive shell. For example:

julia> ;ls
CONTRIBUTING.md  Makefile           VERSION      deps/      julia@  ui/
DISTRIBUTING.md  NEWS.md            Windows.inc  doc/       src/    usr/
LICENSE.md       README.md          base/        etc/       test/
Make.inc         README.windows.md  contrib/     examples/  tmp/

New library functions

Sampling profiler (#2597).
Functions for examining stages of the compiler's output: code_lowered, code_typed, code_llvm, and code_native.
Multimedia I/O API (display, writemime, etcetera) (#3932).
MPFR-based BigFloat (#2814), and many new BigFloat operations.
New half-precision IEEE floating-point type, Float16 (#3467).
Support for setting floating-point rounding modes (#3149).
methodswith shows all methods with an argument of specific type.
mapslices provides a general way to perform operations on slices of arrays (#2204).
repeat function for constructing Arrays with repeated elements (#3605).
Collections.PriorityQueue type and Collections.heap functions (#2920).
quadgk 1d-integration routine (#3140).
erfinv and erfcinv functions (#2987).
varm, stdm (#2265).
digamma, invdigamma, trigamma and polygamma for calculating derivatives of gamma function (#3233).
logdet (#3070).
Names for C-compatible types: Cchar, Clong, etc. (#2370).
cglobal to access global variables (#1815).
unsafe_pointer_to_objref (#2468) and pointer_from_objref (#2515).
readandwrite for external processes.
I/O functions readbytes and readbytes! (#3878).
flush_cstdio function (#3949).
ClusterManager makes it possible to support different types of compute clusters (#3649, #4014).
rmprocs for removing processors from a parallel computing session. The system can also tolerate to some extent processors that die unexpectedly (#3050).
interrupt for interrupting worker processes (#3819).
timedwait does a polled wait for an event till a specified timeout.
Condition type with wait and notify functions for Task synchronization.
versioninfo provides detailed version information, especially useful when reporting and diagnosing bugs.
detach for running child processes in a separate process group.
setenv for passing environment variables to child processes.
ifelse eagerly-evaluated conditional function, especially useful for vectorized conditionals.

Library improvements

isequal now returns false for numbers of different types. This makes it much easier to define hashing for new numeric types. Uses of Dict with numeric keys might need to change to account for this increased strictness.
A redesigned and rewritten Pkg system is much more robust in case of problems. The basic interface to adding and removing package requirements remains the same, but great deal of additional functionality for developing packages in-place was added. See the new packages chapter in the manual for further details.
Sorting API updates (#3665) – see sorting functions.
The delete!(d::Dict, key) function has been split into separate pop! and delete! functions (#3439). pop!(d,key) removes key from d and returns the value that was associated with it; it throws an exception if d does not contain key. delete!(d,key) removes key from d and succeeds regardless of whether d contained key or not, returning d itself in either case.
Linear-algebra factorization routines (lu, chol, etc.) now return Factorization objects (and lud, chold, etc. are deprecated; #2212).
A number of improvements to sparse matrix capabilities and sparse linear algebra.
More linear algebra fixes and eigensolver hooks for SymTridiagonal, Tridiagonal and Bidiagonal matrix types (#2606, #2608, #2609, #2611, #2678, #2713, #2720, #2725).
Change integer_valued, real_valued, and so on to isinteger, isreal, and so on, and semantics of the later are now value-based rather than type-based, unlike MATLAB/Octave (#3071). isbool and iscomplex are eliminated in favor of a general iseltype function.
Transitive comparison of floats with rationals (#3102).
Fast prime generation with primes and fast primality testing with isprime.
sum and cumsum now use pairwise summation for better accuracy (#4039).
Dot operators (.+, .* etc.) now broadcast singleton dimensions of array arguments. This behavior can be applied to any function using broadcast(f, ...).
combinations, permutations, and partitions now return iterators instead of a task, and integer_partitions has been renamed to partitions (#3989, #4055).
isreadable/iswritable methods added for more IO types (#3872).
Much faster and improved readdlm and writedlm (#3350, #3468, #3483).
Faster matchall (#3719), and various string and regex improvements.
Documentation of advanced linear algebra features (#2807).
Support optional RTLD flags in dlopen (#2380).
pmap now works with any iterable collection.
Options in pmap for retrying or ignoring failed tasks.
New sinpi(x) and cospi(x) functions to compute sine and cosine of pi*x more accurately (#4112).
New implementations of elementary complex functions sqrt, log, asin, acos, atan, tanh, asinh, acosh, atanh with correct branch cuts (#2891).
Improved behavior of SubArray (#4412, #4284, #4044, #3697, #3790, #3148, #2844, #2644 and various other fixes).
New convenience functions in graphics API.
Improved backtraces on Windows and OS X.
Implementation of reduction functions (including reduce, mapreduce, sum, prod, maximum, minimum, all, and any) are refactored, with improved type stability, efficiency, and consistency (#6116, #7035, #7061, #7106).

Deprecated or removed

Methods of min and max that do reductions were renamed to minimum and maximum. min(x) is now minimum(x), and min(x,(),dim) is now minimum(x,dim) (#4235).
ComplexPair was renamed to Complex and made immutable, and Complex128 and so on are now aliases to the new Complex type.
! was added to the name of many mutating functions, e.g., push was renamed push! (#907).
ref renamed to getindex, and assign to setindex! (#1484).
writeable renamed to writable (#3874).
logb and ilogb renamed to exponent (#2516).
quote_string became a method of repr.
safe_char, check_ascii, and check_utf8 replaced by is_valid_char, is_valid_ascii, and is_valid_utf8, respectively.
each_line, each_match, begins_with, ends_with, parse_float, parse_int, and seek_end replaced by: eachline, eachmatch, and so on (_ was removed) (#1539).
parse_bin(s) replaced by parseint(s,2); parse_oct(s) replaced by parseint(s,8); parse_hex(s) replaced by parseint(s,16).
findn_nzs replaced by findnz (#1539).
DivideByZeroError replaced by DivideError.
addprocs_ssh, addprocs_ssh_tunnel, and addprocs_local replaced by addprocs (with keyword options).
remote_call, remote_call_fetch, and remote_call_wait replaced by remotecall, remotecall_fetch, and remotecall_wait.
has replaced by in for sets and by haskey for dictionaries.
diagmm and diagmm! replaced by scale and scale! (#2916).
unsafe_ref and unsafe_assign replaced by unsafe_load and unsafe_store!.
add_each! and del_each! replaced by union! and setdiff!.
isdenormal renamed to issubnormal (#3105).
expr replaced by direct call to Expr constructor.
|, &, $, -, and ~ for sets replaced by union, intersect, symdiff, setdiff, and complement (#3272).
square function removed.
pascal function removed.
add and add! for Set replaced by push!.
ls function deprecated in favor of readdir or ;ls in the REPL.
start_timer now expects arguments in units of seconds, not milliseconds.
Shell redirection operators |, >, and < eliminated in favor of a new operator |> (#3523).
amap is deprecated in favor of new mapslices functionality.
The Reverse iterator was removed since it did not work in many cases.
The gcd function now returns a non-negative value regardless of the argument signs, and various other sign problems with invmod, lcm, gcdx, and powermod were fixed (#4811).

Miscellaneous changes

julia-release-* executables renamed to julia-*, and libjulia-release renamed to libjulia (#4177).
Packages will now be installed in .julia/vX.Y, where X.Y is the current Julia version.

Bugfixes and performance updates

Too numerous to mention.

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