rPackages.torch: use binary

pkgs/development/r-modules/default.nix

@@ -1803,10 +1803,23 @@ let
       '';
     });
 
-    torch = old.torch.overrideAttrs (attrs: {
-      preConfigure = ''
-        patchShebangs configure
-      '';
+    torch = let
+      # Sets the correct string to download either the binary for
+      # the cpu version of the torch package, or the
+      # the cuda-enabled version.
+      # To use gpu acceleration, set `config.cudaSupport = true;`
+      # when importing nixpkgs in your shell
+       accel = if pkgs.config.cudaSupport then "cu118" else "cpu";
+
+       binary_sha = if pkgs.config.cudaSupport then
+         "sha256-a80sG89C0svZzkjNRpY0rTR2P1JdvKAbWDGIIghsv2Y=" else
+         "sha256-qUn8Rot6ME7iTvtNd52iw3ebqMnpLz7kwl/9GoPHD+I=";
+      in
+     old.torch.overrideAttrs (attrs: {
+      src = pkgs.fetchzip {
+       url = "https://torch-cdn.mlverse.org/packages/${accel}/0.13.0/src/contrib/torch_0.13.0_R_x86_64-pc-linux-gnu.tar.gz";
+       sha256 = binary_sha;
+      };
     });
 
     pak = old.pak.overrideAttrs (attrs: {