public override void Update(NDArray labels, NDArray preds)
{
CheckLabelShapes(labels, preds);
var pred_label = preds.Argsort().AsNumpy().astype(NPTypeCode.Int32); //ToDo: Use numpy argpartition
var label = labels.AsNumpy().astype(NPTypeCode.Int32);
var num_samples = pred_label.shape[0];
var num_dims = pred_label.shape.Length;
if (num_dims == 1)
{
sum_metric += (pred_label.flat == label.flat).sum();
}
else if (num_dims == 2)
{
var num_classes = pred_label.shape[1];
TopK = Math.Min(num_classes, TopK);
for (var j = 0; j < TopK; j++)
{
float num_correct = (pred_label[":", num_classes - 1 - j].flat == label.flat).sum();
sum_metric += num_correct;
global_sum_metric += num_correct;
}
}
num_inst += num_samples;
global_num_inst += num_samples;
}
public override void Update(NDArray labels, NDArray preds)
{
var label = labels.AsType(DType.Int32).AsNumpy();
var pred = np.argmax(preds.AsNumpy(), 1).astype(NPTypeCode.Int32);
var n = np.max(pred.max(), label.max()).Data <int>()[0];
if (n >= k)
{
Grow(n + 1 - k);
}
var bcm = np.zeros(k, k);
pred.Data <int>().Zip(label.Data <int>(), (i, j) =>
{
bcm[i, j] += 1;
return(true);
});
lcm += bcm;
gcm += bcm;
num_inst += 1;
global_num_inst += 1;
}
public override void Update(NDArray labels, NDArray preds)
{
var l = labels.AsNumpy();
if (preds.Shape[0] != labels.Shape[0])
{
throw new ArgumentException("preds.Shape[0] != labels.Shape[0]");
}
l = l.ravel();
var p = preds.AsNumpy();
var prob = p[np.arange(l.shape.iDims[0]), l.astype(np.Int64)];
var cross_entropy = np.sum(-np.log((ndarray)prob + eps)).asscalar <float>();
sum_metric += sum_metric;
global_sum_metric += sum_metric;
num_inst += (int)l.shape.iDims[0];
global_num_inst += (int)l.shape.iDims[0];
}
private float CalcMcc(NDArray cmatArr)
{
var cmat = cmatArr.AsNumpy();
var n = cmat.sum();
var x = cmat.sum(1);
var y = cmat.sum(0);
var cov_xx = np.sum(x * (n - x)).Data <float>()[0];
var cov_yy = np.sum(y * (n - y)).Data <float>()[0];
if (cov_xx == 0 || cov_yy == 0)
{
return(float.NaN);
}
var i = cmatArr.Diag().AsNumpy();
var cov_xy = np.sum(i * n - x * y);
return(np.power(cov_xy / (cov_xx * cov_yy), 0.5));
}
public override void Update(NDArray labels, NDArray preds)
{
CheckLabelShapes(labels, preds);
if (preds.Shape[0] != labels.Shape[0])
{
throw new ArgumentException("preds.Shape[0] != labels.Shape[0]");
}
var l = labels.AsNumpy();
l = l.ravel();
var p = preds.AsNumpy();
var num_examples = p.shape[0];
var prob = p[np.arange(num_examples).astype(NPTypeCode.Int64), l.astype(NPTypeCode.UInt64)];
var nll = (-np.log(prob + eps)).sum().Data <float>()[0];
sum_metric += nll;
global_sum_metric += nll;
num_inst += num_examples;
global_num_inst += num_examples;
}
public override NDArrayOrSymbol Forward(NDArrayOrSymbol x, params NDArrayOrSymbol[] args)
{
NDArray img = x;
NDArrayList xs = args[0].NdXList;
NDArray anchors = args[1];
NDArray offsets = args[2];
NDArray gt_boxes = args[3];
NDArray gt_ids = args[4];
NDArray gt_mixratio = args[5];
var all_anchors = nd.Concat((from i in Enumerable.Range(0, anchors.Shape[0])
select anchors[i].Reshape(-1, 2)).ToList(), dim: 0);
var all_offsets = nd.Concat((from i in Enumerable.Range(0, anchors.Shape[0])
select offsets[i].Reshape(-1, 2)).ToList(), dim: 0);
var l = (from i in Enumerable.Range(0, anchors.Shape[0])
select(anchors[i].Size / 2)).ToArray();
var num_anchors = np.cumsum(np.array((from i in Enumerable.Range(0, anchors.Shape[0])
select(anchors[i].Size / 2)).ToArray()));
var num_offsets = np.cumsum(np.array((from i in Enumerable.Range(0, offsets.Shape[0])
select(offsets[i].Size / 2)).ToArray()));
var _offsets = new List <int> {
0
};
_offsets.AddRange(num_offsets.AsInt32Array());
Debug.Assert((xs.Length == anchors.Shape[0]) && (anchors.Shape[0] == offsets.Shape[0]));
// orig image size
var orig_height = img.Shape[2];
var orig_width = img.Shape[3];
ndarray center_targets = null;
ndarray scale_targets = null;
ndarray weights = null;
ndarray objectness = null;
ndarray class_targets = null;
using (var ag = Autograd.Pause())
{
// outputs
var shape_like = all_anchors.Reshape(1, -1, 2) * all_offsets.Reshape(-1, 1, 2).ExpandDims(0).Repeat(repeats: gt_ids.Shape[0], axis: 0);
center_targets = nd.ZerosLike(shape_like);
scale_targets = nd.ZerosLike(shape_like);
weights = nd.ZerosLike(shape_like);
objectness = nd.ZerosLike(nd.Split(weights, axis: -1, num_outputs: 2)[0]);
class_targets = nd.OneHot(nd.Squeeze(new NDArrayList(objectness), axis: new Shape(-1)), depth: this._num_class);
class_targets[":"] = -1;
// for each ground-truth, find the best matching anchor within the particular grid
// for instance, center of object 1 reside in grid (3, 4) in (16, 16) feature map
// then only the anchor in (3, 4) is going to be matched
var _tup_1 = this.bbox2center.Call(gt_boxes);
NDArray gtx = _tup_1[0];
NDArray gty = _tup_1[1];
NDArray gtw = _tup_1[2];
NDArray gth = _tup_1[3];
var shift_gt_boxes = nd.Concat(new NDArrayList(-0.5f * gtw, -0.5f * gth, 0.5f * gtw, 0.5f * gth), dim: -1);
var anchor_boxes = nd.Concat(new NDArrayList(0 * all_anchors, all_anchors), dim: -1);
var shift_anchor_boxes = this.bbox2corner.Call(anchor_boxes);
var ious = nd.Contrib.BoxIou(shift_anchor_boxes, shift_gt_boxes).Transpose(new Shape(1, 0, 2));
// real value is required to process, convert to Numpy
var matches = ious.Argmax(axis: 1).AsNumpy();
var valid_gts = (gt_boxes >= 0).Prod(axis: -1).ArrayData;
var np_gtx = gtx.AsNumpy();
var np_gty = gty.AsNumpy();
var np_gtw = gtw.AsNumpy();
var np_gth = gth.AsNumpy();
var np_anchors = all_anchors.AsNumpy();
var np_gt_ids = gt_ids.AsNumpy();
var np_gt_mixratios = gt_mixratio != null?gt_mixratio.AsNumpy() : null;
// TODO(zhreshold): the number of valid gt is not a big number, therefore for loop
// should not be a problem right now. Switch to better solution is needed.
foreach (var b in Enumerable.Range(0, (int)matches.shape.iDims[0]))
{
foreach (var m in Enumerable.Range(0, (int)matches.shape.iDims[1]))
{
if ((int)valid_gts.GetValue(b, m) < 1)
{
break;
}
var match = Convert.ToInt32(matches[b, m]);
var nlayer = (int)np.nonzero(num_anchors > match)[0][0];
var height = xs[nlayer].Shape[2];
var width = xs[nlayer].Shape[3];
var(gtx_bm, gty_bm, gtw_bm, gth_bm) = ((ndarray)np_gtx[b, m, 0], (ndarray)np_gty[b, m, 0], (ndarray)np_gtw[b, m, 0], (ndarray)np_gth[b, m, 0]);
// compute the location of the gt centers
var loc_x = Convert.ToInt32(gtx / orig_width * width);
var loc_y = Convert.ToInt32(gty / orig_height * height);
// write back to targets
var index = _offsets[nlayer] + loc_y * width + loc_x;
center_targets[b, index, match, 0] = gtx_bm / orig_width * width - loc_x;
center_targets[b, index, match, 1] = gty_bm / orig_height * height - loc_y;
scale_targets[b, index, match, 0] = np.log(np.maximum(gtw_bm, 1) / np_anchors[match, 0]);
scale_targets[b, index, match, 1] = np.log(np.maximum(gth_bm, 1) / np_anchors[match, 1]);
weights[b, index, match, ":"] = 2 - gtw * gth / orig_width / orig_height;
objectness[b, index, match, 0] = np_gt_mixratios != null ? np_gt_mixratios[b, m, 0] : 1;
class_targets[b, index, match, ":"] = 0;
class_targets[b, index, match, Convert.ToInt32(np_gt_ids[b, m, 0])] = 1;
}
}
// since some stages won't see partial anchors, so we have to slice the correct targets
objectness = this.Slice(objectness, num_anchors, num_offsets);
center_targets = this.Slice(center_targets, num_anchors, num_offsets);
scale_targets = this.Slice(scale_targets, num_anchors, num_offsets);
weights = this.Slice(weights, num_anchors, num_offsets);
class_targets = this.Slice(class_targets, num_anchors, num_offsets);
}
return(new NDArrayOrSymbol(objectness, center_targets, scale_targets, weights, class_targets));
}