diff --git a/SciLean/Modules/ML/SoftMax.lean b/SciLean/Modules/ML/SoftMax.lean
new file mode 100644
index 00000000..25ef61e6
--- /dev/null
+++ b/SciLean/Modules/ML/SoftMax.lean
@@ -0,0 +1,39 @@
+import SciLean.Core
+import SciLean.Data.DataArray
+import SciLean.Data.Prod
+import Mathlib
+
+namespace SciLean.ML
+
+variable 
+  {R : Type} [RealScalar R] [PlainDataType R]
+
+set_default_scalar R
+
+def softMax
+  {ι} [Index ι] (r : R) (x : R^ι) : R^ι := 
+  let wx := Function.repeatIdx (init:=((0:R),x)) 
+    fun (i : ι) (w,x) => 
+      let xi := x[i]
+      let xi' := Scalar.exp (r*xi)
+      (w + xi', setElem x i (xi * xi'))
+  -- have : ∀ x :R, x ≠ 0 := by sorry_proof
+  wx.2
+
+@[fprop]
+theorem Scalar.exp.arg_x.HasAdjDiff_rule 
+  {R K} [Scalar R K] {W} [SemiInnerProductSpace K W]
+  (x : W → K) (hx : HasAdjDiff K x)
+  : HasAdjDiff K (fun w => Scalar.exp (x w)) := by sorry_proof
+
+
+-- set_option trace.Meta.Tactic.fprop.discharge true 
+-- set_option trace.Meta.Tactic.fprop.step true 
+-- set_option trace.Meta.Tactic.fprop.apply true 
+-- set_option trace.Meta.Tactic.fprop.rewrite true
+-- set_option trace.Meta.Tactic.fprop.unify true
+set_option trace.Meta.Tactic.ftrans.step true
+set_option trace.Meta.Tactic.simp.discharge true
+-- #generate_revDeriv softMax r x
+--   prop_by unfold softMax; sorry_proof --fprop
+--   trans_by unfold softMax; ftrans