MLBEDSW-2067: added custom exceptions

Added custom exceptions to handle different types of input errors.

Also performed minor formatting changes using flake8/black.

Change-Id: Ie5b05361507d5e569aff045757aec0a4a755ae98
Signed-off-by: Louis Verhaard <louis.verhaard@arm.com>

1 files changed, 7 insertions, 2 deletions

diff --git a/ethosu/vela/weight_compressor.py b/ethosu/vela/weight_compressor.py
index 04d684e6..a81b1fb4 100644
--- a/ethosu/vela/weight_compressor.py
+++ b/ethosu/vela/weight_compressor.py
@@ -23,6 +23,7 @@ from ethosu import mlw_codec
 
 from .architecture_features import Block
 from .data_type import DataType
+from .errors import UnsupportedFeatureError
 from .nn_graph import SchedulingStrategy
 from .numeric_util import round_up
 from .operation import NpuBlockType
@@ -292,14 +293,18 @@ def calc_scales_and_pack_biases(tens, arch, oc_quantum, rescale_for_faf=False):
                 for weight_scale in weight_scales
             ]
         else:
-            assert False, str(ifm_dtype) + " not implemented"
+            raise UnsupportedFeatureError(
+                "Compression of {} is not implemented; tensor: {}".format(ifm_dtype, tens.name)
+            )
     else:
         if ifm_dtype == DataType.uint8:
             scales = [np.double(ifm_scale * weight_scale * 0x3000) for weight_scale in weight_scales]
         elif ifm_dtype == DataType.int8 or ifm_dtype == DataType.int16:
             scales = [(np.double(ifm_scale * 0x3000) * np.double(weight_scale)) for weight_scale in weight_scales]
         else:
-            assert False, str(ifm_dtype) + " not implemented"
+            raise UnsupportedFeatureError(
+                "Compression of {} is not implemented; tensor: {}".format(ifm_dtype, tens.name)
+            )
 
     # quantise all of the weight scales into (scale_factor, shift)
     if ifm_dtype == DataType.int16: