Fix sigmoid gradient calculation and move sigmoid into a specialized op (#2114)

* add sigmoid op

* small fix

* add as a method on `Tensor`

* implement gradient calculation for sigmoid

* add sigmoid tests

* we should have a specialized op for this

* fix clippy

* fix clippy 2

* Revert all previous commits in favor of a `CustomOp` based solution

* use `CustomOp1` implementation

* fix rustfmt

* experimental add metal impl

* add cuda kernel impl

* fix fmt

* Add a test + reduce some cuda duplication.

---------

Co-authored-by: laurent <laurent.mazare@gmail.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/candle-core/src/cuda_backend/mod.rs b/candle-core/src/cuda_backend/mod.rs
index a82c89ee..67ed56e0 100644
--- a/candle-core/src/cuda_backend/mod.rs
+++ b/candle-core/src/cuda_backend/mod.rs
@@ -18,7 +18,7 @@ pub use device::{CudaDevice, DeviceId};
 pub use error::{CudaError, WrapErr};
 pub use utils::{Map1, Map1Any, Map2, Map2Any, Map2InPlace, S};
 
-enum SlicePtrOrNull<T> {
+pub enum SlicePtrOrNull<T> {
     Ptr(CudaSlice<T>),
     Null,
 }
@@ -33,7 +33,7 @@ unsafe impl<T: DeviceRepr> DeviceRepr for &SlicePtrOrNull<T> {
 }
 
 impl SlicePtrOrNull<usize> {
-    fn params_from_layout(dev: &CudaDevice, l: &Layout) -> Result<Self> {
+    pub fn params_from_layout(dev: &CudaDevice, l: &Layout) -> Result<Self> {
         let ds = if l.is_contiguous() {
             SlicePtrOrNull::Null
         } else {