MAINT: Fix rayon, serde, blas features for no-std changes

rayon: implies std, because threads to
serde: works fine without std
blas: works fine without std if we use libc (libc is a new dependency
for this feature flag, but it's already used by blas transitively).

A slight hack is used for rayon (renaming the dependency) because we
need to use a feature flag to enable std in this crate too.

Author: bluss

Cargo.toml

@@ -32,16 +32,18 @@ num-integer = { version = "0.1.39", default-features = false }
 num-traits = { version = "0.2", default-features = false }
 num-complex = { version = "0.3", default-features = false }
 
-rayon = { version = "1.0.3", optional = true }
+# Use via the `rayon` crate feature!
+rayon_ = { version = "1.0.3", optional = true, package = "rayon" }
 
 approx = { version = "0.4", optional = true , default-features = false }
 
 # Use via the `blas` crate feature!
 cblas-sys = { version = "0.1.4", optional = true, default-features = false }
 blas-src = { version = "0.6.1", optional = true, default-features = false }
+libc = { version = "0.2.82", optional = true }
 
 matrixmultiply = { version = "0.2.0", default-features = false}
-serde = { version = "1.0", optional = true }
+serde = { version = "1.0", optional = true, default-features = false, features = ["alloc"] }
 rawpointer = { version = "0.2" }
 
 [dev-dependencies]
@@ -55,7 +57,7 @@ default = ["std"]
 
 # Enable blas usage
 # See README for more instructions
-blas = ["cblas-sys", "blas-src"]
+blas = ["cblas-sys", "blas-src", "libc"]
 
 # Old name for the serde feature
 serde-1 = ["serde"]
@@ -68,6 +70,7 @@ test = ["test-blas-openblas-sys"]
 docs = ["approx", "serde", "rayon"]
 
 std = ["num-traits/std", "matrixmultiply/std"]
+rayon = ["rayon_", "std"]
 
 [profile.release]
 [profile.bench]

README.rst

@@ -50,7 +50,7 @@ your `Cargo.toml`.
 
 - ``std``
 
-  - Rust Standard Library
+  - Rust standard library (enabled by default)
 
   - This crate can be used without the standard library by disabling the
     default `std` feature. To do so, use this in your `Cargo.toml`:
@@ -63,20 +63,18 @@ your `Cargo.toml`.
 
 - ``serde``
 
-  - Optional, compatible with Rust stable
   - Enables serialization support for serde 1.x
 
 - ``rayon``
 
-  - Optional, compatible with Rust stable
   - Enables parallel iterators, parallelized methods and ``par_azip!``.
+  - Implies std
 
 - ``blas``
 
-  - Optional and experimental, compatible with Rust stable
   - Enable transparent BLAS support for matrix multiplication.
     Uses ``blas-src`` for pluggable backend, which needs to be configured
-    separately.
+    separately (see below).
 
 How to use with cargo
 ---------------------

serialization-tests/Cargo.toml

@@ -15,6 +15,7 @@ default = ["ron"]
 
 [dev-dependencies.serde]
 version = "1.0.100"
+default-features = false
 
 [dev-dependencies.serde_json]
 version = "1.0.40"

src/lib.rs

@@ -70,27 +70,23 @@
 //! `Cargo.toml`.
 //!
 //! - `std`
-//!  - Rust Standard Library
+//!  - Rust standard library (enabled by default)
 //!  - This crate can be used without the standard library by disabling the
 //!    default `std` feature. To do so, use `default-features = false` in
 //!    your `Cargo.toml`.
 //!  - The `geomspace` `linspace` `logspace` `range` `std` `var` `var_axis`
-//!    and `std_axis` methods are only available when `std` is
-//!     enabled.
+//!    and `std_axis` methods are only available when `std` is enabled.
 //! - `serde`
-//!   - Optional, compatible with Rust stable
 //!   - Enables serialization support for serde 1.x
 //! - `rayon`
-//!   - Optional, compatible with Rust stable
 //!   - Enables parallel iterators, parallelized methods and [`par_azip!`].
+//!   - Implies std
 //! - `approx`
-//!   - Optional, compatible with Rust stable
 //!   - Enables implementations of traits from the [`approx`] crate.
 //! - `blas`
-//!   - Optional and experimental, compatible with Rust stable
 //!   - Enable transparent BLAS support for matrix multiplication.
 //!     Uses ``blas-src`` for pluggable backend, which needs to be configured
-//!     separately.
+//!     separately (see the README).
 //!
 //! ## Documentation
 //!
@@ -1594,6 +1590,8 @@ where
 
 // parallel methods
 #[cfg(feature = "rayon")]
+extern crate rayon_ as rayon;
+#[cfg(feature = "rayon")]
 pub mod parallel;
 
 mod impl_1d;

src/linalg/impl_linalg.rs

@@ -19,7 +19,7 @@ use std::cmp;
 #[cfg(feature = "blas")]
 use std::mem::swap;
 #[cfg(feature = "blas")]
-use std::os::raw::c_int;
+use libc::c_int;
 
 #[cfg(feature = "blas")]
 use cblas_sys as blas_sys;