Make lambdaworks-gpu dep in lambdaworks-math optional (#465)

* Remove lambdaworks-gpu dep in lambdaworks-math

* Re-add gpu dependency, but make it optional

Author: MegaRedHand

ensure-no_std/Cargo.toml

@@ -5,9 +5,7 @@ edition = "2021"
 
 
 [dependencies]
-getrandom = { version = "0.2", features = ["js"] }
 lambdaworks-math = { path = "../math", default-features = false }
-wee_alloc = "0.4.5"
 
 [profile.dev]
 panic = "abort"

ensure-no_std/src/main.rs

@@ -14,8 +14,5 @@ fn panic(_info: &PanicInfo) -> ! {
     loop {}
 }
 
-#[global_allocator]
-static ALLOC: wee_alloc::WeeAlloc = wee_alloc::WeeAlloc::INIT;
-
 #[allow(unused_imports)]
-use {lambdaworks_math};
+use lambdaworks_math;

math/Cargo.toml

@@ -8,8 +8,8 @@ license.workspace = true
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-rand = {version = "0.8.5", default-features = false}
-thiserror = "1.0.38"
+rand = { version = "0.8.5", default-features = false }
+thiserror = { version = "1.0.38", optional = true }
 
 # rayon
 rayon = { version = "1.7.0", optional = true }
@@ -22,7 +22,7 @@ objc = { version = "0.2.7", optional = true }
 # cuda
 cudarc = { version = "0.9.7", optional = true }
 
-lambdaworks-gpu.workspace = true
+lambdaworks-gpu = { workspace = true, optional = true }
 
 [dev-dependencies]
 proptest = "1.1.0"
@@ -33,22 +33,21 @@ iai-callgrind.workspace = true
 [features]
 rayon = ["dep:rayon"]
 default = ["rayon", "std"]
-std = []
+std = ["dep:thiserror"]
 
 # gpu
-metal = ["dep:metal", "dep:objc", "lambdaworks-gpu/metal"]
-cuda = ["dep:cudarc"]
+metal = [
+    "dep:metal",
+    "dep:objc",
+    "dep:lambdaworks-gpu",
+    "lambdaworks-gpu?/metal",
+]
+cuda = ["dep:cudarc", "dep:lambdaworks-gpu"]
 
 [[bench]]
 name = "criterion_elliptic_curve"
 harness = false
 
-# gpu
-metal = ["dep:metal", "dep:objc"]
-cuda = ["dep:cudarc"]
-
-rayon = ["dep:rayon"]
-
 [[bench]]
 name = "criterion_polynomial"
 harness = false