[onert-micro] Revise softmax input grad (#14100)

- Fix softmax input grad computation

ONE-DCO-1.0-Signed-off-by: Chunseok Lee <[email protected]>

onert-micro/onert-micro/include/pal/common/PALSoftmaxInputGrad.h

@@ -37,20 +37,25 @@ void inline SoftmaxInputGrad(const float *dloss_doutput_data,
 {
   assert(dloss_doutput_shape.dimensionsCount() == 2);
   assert(dloss_doutput_shape.dims(0) == 1);
-  const uint32_t output_dim = dloss_doutput_shape.dims(dloss_doutput_shape.dimensionsCount() - 1);
-  for (int i = 0; i < output_dim; ++i)
+  const uint32_t width = dloss_doutput_shape.dims(dloss_doutput_shape.dimensionsCount() - 1);
+  for (int w1 = 0; w1 < width; ++w1)
   {
-    for (int j = 0; j < output_dim; ++j)
+    float sum = 0.0f;
+    for (int w2 = 0; w2 < width; ++w2)
     {
-      jacobian_row_data[j] = -calculated_data[i] * calculated_data[j];
+      float val;
+      if (w1 == w2)
+      {
+        val = calculated_data[w2] * (1.f - calculated_data[w2]);
+      }
+      else
+      {
+        val = -calculated_data[w2] * calculated_data[w1];
+      }
+      val *= dloss_doutput_data[w2];
+      sum += val;
     }
-    jacobian_row_data[i] += calculated_data[i];
-    float total = 0.f;
-    for (int j = 0; j < output_dim; ++j)
-    {
-      total += jacobian_row_data[j] * dloss_doutput_data[j];
-    }
-    dloss_dinput_data[i] = total;
+    dloss_dinput_data[w1] = sum;
   }
 }