COMPMID-3694 COMPMID-3695 COMPMID-3458: Softmax Axis

* Properly support "axis" in CL and NEON (and GC) SoftmaxLayer and
LogSoftmaxLayer in accord with mainstream frameworks. Axis now defines
the dimension on which softmax is performed, and supports the range
[-rank, rank)

* Extend validation tests to include valid and invalid axes

* Remove unnecessary LogSoftmaxLayer fixture, as it is only a
specialisation of the SoftmaxLayer fixture

* Change the validation fill value range from [-1000, 1000] to [-10,
10], as the former often results in sparse outputs with a single one and
zeros elsewhere

Change-Id: I8a0040453182b04ed88260de3ba434e98258d863
Signed-off-by: Manuel Bottini <manuel.bottini@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/3830
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Michele Di Giorgio <michele.digiorgio@arm.com>
Reviewed-by: Gian Marco Iodice <gianmarco.iodice@arm.com>

1 files changed, 15 insertions, 10 deletions

diff --git a/arm_compute/core/Helpers.h b/arm_compute/core/Helpers.h
index 48ac38b170..90dd6082e1 100644
--- a/arm_compute/core/Helpers.h
+++ b/arm_compute/core/Helpers.h
@@ -801,16 +801,6 @@ inline T wrap_around(T x, T m)
     return x >= 0 ? x % m : (x % m + m) % m;
 }
 
-/** Convert a dimension axis to the number of dimensions in the range [0, @p dim_axis]
- * Handle negative axis, negative axis is used to specify axis from the end (e.g. -1 for the last axis).
- *
- * @param[in] dim_axis The last axis (inclusive) in the range [0, @p dim_axis]
- * @param[in] num_dims The total number of dimensions
- *
- * @return The number of dimensions in the range [0, @p dim_axis]
- */
-inline size_t dim_index_2_num_dims(int32_t dim_axis, int32_t num_dims);
-
 /** Convert negative coordinates to positive in the range [0, num_dims_input]
  *
  * @param[out] coords    Array of coordinates to be converted.
@@ -852,6 +842,21 @@ inline unsigned int get_next_power_two(unsigned int x)
 
     return x;
 }
+
+/** Given a softmax axis, this function returns the permutation vector required to put the axis to the front
+ *
+ * @note This function assumes a tensor rank <= 4
+ *
+ * Axis selects the dimension on which softmax is performed.
+ * E.g. For input of shape 4x5x6 and axis=1, softmax will be applied to 4x6=24 vectors of size 5.
+ * Interally softmax kernels is always performed on the first dimension (front dimension), therefore permutation is
+ * required to put the dimension specified by @p axis to the first dimension.
+ *
+ * @param[in] axis Axis on which to perform softmax. Supported: 1, 2, 3 (0 implies no permutation needed)
+ *
+ * @return the permutation vector
+ */
+PermutationVector get_permutation_vector_from_softmax_axis(size_t axis);
 } // namespace arm_compute
 
 #include "arm_compute/core/Helpers.inl"