def test_unique_label_indices():
a = np.random.randint(1, 1 << 10, 1 << 15).astype(np.intp)
left = ht.unique_label_indices(a)
right = np.unique(a, return_index=True)[1]
tm.assert_numpy_array_equal(left, right, check_dtype=False)
a[np.random.choice(len(a), 10)] = -1
left = ht.unique_label_indices(a)
right = np.unique(a, return_index=True)[1][1:]
tm.assert_numpy_array_equal(left, right, check_dtype=False)
def decons_obs_group_ids(comp_ids, obs_ids, shape, labels, xnull: bool):
"""
Reconstruct labels from observed group ids.
Parameters
----------
comp_ids : np.ndarray[np.intp]
xnull : bool
If nulls are excluded; i.e. -1 labels are passed through.
"""
if not xnull:
lift = np.fromiter(((a == -1).any() for a in labels), dtype="i8")
shape = np.asarray(shape, dtype="i8") + lift
if not is_int64_overflow_possible(shape):
# obs ids are deconstructable! take the fast route!
out = decons_group_index(obs_ids, shape)
return out if xnull or not lift.any() else [
x - y for x, y in zip(out, lift)
]
# TODO: unique_label_indices only used here, should take ndarray[np.intp]
i = unique_label_indices(ensure_int64(comp_ids))
i8copy = lambda a: a.astype("i8", subok=False, copy=True)
return [i8copy(lab[i]) for lab in labels]
def decons_obs_group_ids(
comp_ids: npt.NDArray[np.intp],
obs_ids: npt.NDArray[np.intp],
shape: Shape,
labels: Sequence[npt.NDArray[np.signedinteger]],
xnull: bool,
) -> list[npt.NDArray[np.intp]]:
"""
Reconstruct labels from observed group ids.
Parameters
----------
comp_ids : np.ndarray[np.intp]
obs_ids: np.ndarray[np.intp]
shape : tuple[int]
labels : Sequence[np.ndarray[np.signedinteger]]
xnull : bool
If nulls are excluded; i.e. -1 labels are passed through.
"""
if not xnull:
lift = np.fromiter(((a == -1).any() for a in labels), dtype=np.intp)
arr_shape = np.asarray(shape, dtype=np.intp) + lift
shape = tuple(arr_shape)
if not is_int64_overflow_possible(shape):
# obs ids are deconstructable! take the fast route!
out = _decons_group_index(obs_ids, shape)
return out if xnull or not lift.any() else [x - y for x, y in zip(out, lift)]
indexer = unique_label_indices(comp_ids)
return [lab[indexer].astype(np.intp, subok=False, copy=True) for lab in labels]
def decons_obs_group_ids(comp_ids, obs_ids, shape, labels, xnull):
"""
reconstruct labels from observed group ids
Parameters
----------
xnull: boolean,
if nulls are excluded; i.e. -1 labels are passed through
"""
if not xnull:
lift = np.fromiter(((a == -1).any() for a in labels), dtype='i8')
shape = np.asarray(shape, dtype='i8') + lift
if not is_int64_overflow_possible(shape):
# obs ids are deconstructable! take the fast route!
out = decons_group_index(obs_ids, shape)
return out if xnull or not lift.any() \
else [x - y for x, y in zip(out, lift)]
i = unique_label_indices(comp_ids)
i8copy = lambda a: a.astype('i8', subok=False, copy=True)
return [i8copy(lab[i]) for lab in labels]
def decons_obs_group_ids(comp_ids, obs_ids, shape, labels, xnull):
"""
reconstruct labels from observed group ids
Parameters
----------
xnull: boolean,
if nulls are excluded; i.e. -1 labels are passed through
"""
if not xnull:
lift = np.fromiter(((a == -1).any() for a in labels), dtype='i8')
shape = np.asarray(shape, dtype='i8') + lift
if not is_int64_overflow_possible(shape):
# obs ids are deconstructable! take the fast route!
out = decons_group_index(obs_ids, shape)
return out if xnull or not lift.any() \
else [x - y for x, y in zip(out, lift)]
i = unique_label_indices(comp_ids)
i8copy = lambda a: a.astype('i8', subok=False, copy=True)
return [i8copy(lab[i]) for lab in labels]
def test_unique_label_indices_intp(writable):
keys = np.array([1, 2, 2, 2, 1, 3], dtype=np.intp)
keys.flags.writeable = writable
result = ht.unique_label_indices(keys)
expected = np.array([0, 1, 5], dtype=np.intp)
tm.assert_numpy_array_equal(result, expected)
def get_map_for_class(zipped_data_arr,
min_ious=np.linspace(.50, 0.95, 10, endpoint=True),
avg_recalls=np.linspace(0.00, 1.00, 101, endpoint=True),
nms_iou=.7):
# Used linspace over arange for min_ious/avg_recalls due to issues with endpoints
all_confs = []
all_correct_preds = []
num_total_detections = 0
num_total_gtruths = 0
for ground_arr, detector_arr in zipped_data_arr:
num_gtruths = len(ground_arr)
if not detector_arr:
num_total_gtruths += num_gtruths
continue
detector_arr = np.asarray(detector_arr, dtype=np.float64)
# Sort by descending confidence, use mergesort to match COCO evaluation
detector_arr = detector_arr[detector_arr[:, -1].argsort(
kind='mergesort')[::-1]]
det_x_min, det_x_max, det_y_min, det_y_max, confs = detector_arr.transpose(
)
if nms_iou is not None:
# Code for NMS
all_indices_to_keep = []
cur_indices_to_keep = np.arange(len(detector_arr))
# Repeat until no detections left below overlap threshold
while cur_indices_to_keep.size > 1:
# Add the most confident element
all_indices_to_keep.append(cur_indices_to_keep[0])
cur_x_min = det_x_min[cur_indices_to_keep]
cur_x_max = det_x_max[cur_indices_to_keep]
cur_y_min = det_y_min[cur_indices_to_keep]
cur_y_max = det_y_max[cur_indices_to_keep]
intersect_widths = (
np.minimum(cur_x_max[0], cur_x_max[1:]) -
np.maximum(cur_x_min[0], cur_x_min[1:])).clip(min=0)
intersect_heights = (
np.minimum(cur_y_max[0], cur_y_max[1:]) -
np.maximum(cur_y_min[0], cur_y_min[1:])).clip(min=0)
intersect_areas = intersect_widths * intersect_heights
# Inclusion exclusion principle!
union_areas = (
(cur_x_max[0] - cur_x_min[0]) *
(cur_y_max[0] - cur_y_min[0]) +
(cur_x_max[1:] - cur_x_min[1:]) *
(cur_y_max[1:] - cur_y_min[1:])) - intersect_areas
# Just in case a ground truth has zero area
cur_ious = np.divide(intersect_areas,
union_areas,
out=union_areas,
where=union_areas != 0)
# Keep appending [0] to a list
# Just say cur_indices = np where cur_ious < nms_iou
cur_indices_to_keep = cur_indices_to_keep[1:]
cur_indices_to_keep = np.intersect1d(
cur_indices_to_keep,
cur_indices_to_keep[np.nonzero(cur_ious < nms_iou)[0]],
assume_unique=True)
if cur_indices_to_keep.size == 1:
all_indices_to_keep.append(cur_indices_to_keep[0])
detector_arr = detector_arr[np.asarray(all_indices_to_keep)]
det_x_min, det_x_max, det_y_min, det_y_max, confs = detector_arr.transpose(
)
num_detections = len(detector_arr)
if not ground_arr:
num_total_detections += num_detections
all_confs.append(confs)
continue
ground_arr = np.asarray(ground_arr, dtype=np.float64)
ground_x_min, ground_x_max, ground_y_min, ground_y_max = ground_arr.transpose(
)
# Clip negative since negative implies no overlap
intersect_widths = (
np.minimum(det_x_max[:, np.newaxis], ground_x_max) -
np.maximum(det_x_min[:, np.newaxis], ground_x_min)).clip(min=0)
intersect_heights = (
np.minimum(det_y_max[:, np.newaxis], ground_y_max) -
np.maximum(det_y_min[:, np.newaxis], ground_y_min)).clip(min=0)
intersect_areas = intersect_widths * intersect_heights
# Inclusion exclusion principle!
union_areas = ((det_x_max - det_x_min) *
(det_y_max - det_y_min))[:, np.newaxis] + (
(ground_x_max - ground_x_min) *
(ground_y_max - ground_y_min)) - intersect_areas
# Just in case a ground truth has zero area
iou = np.divide(intersect_areas,
union_areas,
out=union_areas,
where=union_areas != 0)
# Defined best ground truth as one with highest IOU. This is an array of size num_detections, where
# best_gtruths[i] is the index of the ground truth to which prediction i is most similar (highest IOU)
best_gtruths = np.argmax(iou, axis=1)
# valid_preds is a generator where each element is a numpy int array. Each numpy array corresponds to
# a min_iou in the min_ious array, and has indices corresponding to the predictions whose
# prediction-ground truth pairs have IOU greater than that min_iou.
valid_preds = map(
np.nonzero, iou[np.arange(num_detections), best_gtruths] >
min_ious[:, np.newaxis])
#
## Useful for standard precision/recall metrics
# num_true_positives = np.count_nonzero(np.bincount(best_gtruths[valid_preds]))
# num_false_positives = num_detections - detected_gtruths
# num_false_negatives = num_gtruths - detected_gtruths
#
# best_gtruths[valid_preds] uses the previously calculated valid_preds array to return an array
# containing the ground truths indices for each prediction whenever the ground truth-prediction
# IOU was greater than min_iou. Then unique_label_indices is used to find the leftmost occuring
# ground truth index for each ground truth index, which corresponds to finding the true positives
# (since we only consider the highest confidence prediction for each ground truth to be a true
# positive, rest are false positives)
# Note that pandas unique_label_indices is equivalent to np.unique(labels, return_index=True)[1] but
# is considerably faster due to using a hashtable instead of sorting
# Once the indices of the true positive predictions are found in the smaller array containing only
# predictions with IOU > min_iou, they are converted back into indices for the original array
# using valid_pred.
correct_preds = [
valid_pred[0][unique_label_indices(best_gtruths[valid_pred[0]])] +
num_total_detections for valid_pred in valid_preds
]
all_correct_preds.append(correct_preds)
all_confs.append(confs)
num_total_detections += num_detections
num_total_gtruths += num_gtruths
# Edge case of no predictions for a class
if not all_confs:
return 0
# Concatenates all predictions and confidences together to find class MAP
all_confs = np.concatenate(all_confs)
all_correct_preds = [
np.concatenate(cur_pred) for cur_pred in zip(*all_correct_preds)
]
# Sets only correct prediction indices to true, rest to false.
true_positives = np.zeros((len(min_ious), num_total_detections),
dtype=bool)
for iou_index, positive_locs in enumerate(all_correct_preds):
true_positives[iou_index][positive_locs] = True
# Mergesort is chosen to be consistent with coco/matlab results
sort_order = all_confs.argsort(kind='mergesort')[::-1]
true_positives = true_positives[:, sort_order]
# Keeps track of number of true positives until each given point
all_true_positives = np.cumsum(true_positives, axis=1)
# PASCAL VOC 2012
if avg_recalls is None:
# Zero pad both sides to calculate area under curve
precision = np.zeros((len(min_ious), num_total_detections + 2),
dtype=np.float64)
# Pad one side with zeros and the other with ones for area under curve
recall = np.zeros((len(min_ious), num_total_detections + 2),
dtype=np.float64)
recall[:, -1] = np.ones(len(min_ious), dtype=np.float64)
# In python >=3 this is equivalent to np.true_divide
precision[:, 1:-1] = all_true_positives / np.arange(
1, num_total_detections + 1)
# Makes each element in precision list max of all elements to right (ignores endpoints)
precision[:, 1:-1] = np.maximum.accumulate(precision[:, -2:0:-1],
axis=1)[:, ::-1]
recall[:, 1:-1] = all_true_positives / num_total_gtruths
# Calculate area under P-R curve for each IOU
# Should only be one IOU at .5 for PASCAL
all_areas = []
for cur_recall, cur_precision in zip(recall, precision):
# Find indices where value of recall changes
change_points = np.nonzero(cur_recall[1:] != cur_recall[:-1])[0]
# Calculate sum of dw * dh as area and append to all areas
all_areas.append(
np.sum(
(cur_recall[change_points + 1] - cur_recall[change_points])
* cur_precision[change_points + 1]))
return np.mean(all_areas)
# PASCAL VOC 2007
else:
# The extra zero is to deal with a recall larger than is achieved by model
precision = np.zeros((len(min_ious), num_total_detections + 1),
dtype=np.float64)
# In python >=3 this is equivalent to np.true_divide
precision[:, :-1] = all_true_positives / np.arange(
1, num_total_detections + 1)
# Makes each element in precision list max of all elements to right (extra zero at right doesn't matter)
precision = np.maximum.accumulate(precision[:, ::-1], axis=1)[:, ::-1]
recall = all_true_positives / num_total_gtruths
# For each recall, finds leftmost index (i.e. largest precision) greater than it
indices_to_average = np.apply_along_axis(np.searchsorted, 1, recall,
avg_recalls)
# Finds matching largest prediction for each recall and turns it into an array
precs_to_average = precision[np.arange(len(precision))[:, np.newaxis],
indices_to_average]
# Returns average precision over each recall and over each IOU. Can specify an axis
# if separate average precision is wanted for each IOU (e.g. to do more precise statistics)
return np.mean(precs_to_average)
