fastreid.layers.arc_softmax.ArcSoftmax Class Reference

Inheritance diagram for fastreid.layers.arc_softmax.ArcSoftmax:

Public Member Functions
	__init__ (self, cfg, in_feat, num_classes)
	forward (self, features, targets)
	extra_repr (self)

Public Attributes
	in_feat
	s
	m
	cos_m
	sin_m
	threshold
	mm
	weight
	t

Protected Attributes
	_num_classes

Detailed Description

Definition at line 15 of file arc_softmax.py.

Constructor & Destructor Documentation

__init__()

fastreid.layers.arc_softmax.ArcSoftmax.__init__	(		self,
			cfg,
			in_feat,
			num_classes )

Definition at line 16 of file arc_softmax.py.

    def __init__(self, cfg, in_feat, num_classes):
        super().__init__()
        self.in_feat = in_feat
        self._num_classes = num_classes
        self.s = cfg.MODEL.HEADS.SCALE
        self.m = cfg.MODEL.HEADS.MARGIN
 
        self.cos_m = math.cos(self.m)
        self.sin_m = math.sin(self.m)
        self.threshold = math.cos(math.pi - self.m)
        self.mm = math.sin(math.pi - self.m) * self.m
 
        self.weight = Parameter(torch.Tensor(num_classes, in_feat))
        nn.init.xavier_uniform_(self.weight)
        self.register_buffer('t', torch.zeros(1))
 

Member Function Documentation

extra_repr()

fastreid.layers.arc_softmax.ArcSoftmax.extra_repr

(

self

)

Definition at line 52 of file arc_softmax.py.

    def extra_repr(self):
        return 'in_features={}, num_classes={}, scale={}, margin={}'.format(
            self.in_feat, self._num_classes, self.s, self.m
        )

forward()

fastreid.layers.arc_softmax.ArcSoftmax.forward	(		self,
			features,
			targets )

Definition at line 32 of file arc_softmax.py.

    def forward(self, features, targets):
        # get cos(theta)
        cos_theta = F.linear(F.normalize(features), F.normalize(self.weight))
        cos_theta = cos_theta.clamp(-1, 1)  # for numerical stability
 
        target_logit = cos_theta[torch.arange(0, features.size(0)), targets].view(-1, 1)
 
        sin_theta = torch.sqrt(1.0 - torch.pow(target_logit, 2))
        cos_theta_m = target_logit * self.cos_m - sin_theta * self.sin_m  # cos(target+margin)
        mask = cos_theta > cos_theta_m
        final_target_logit = torch.where(target_logit > self.threshold, cos_theta_m, target_logit - self.mm)
 
        hard_example = cos_theta[mask]
        with torch.no_grad():
            self.t = target_logit.mean() * 0.01 + (1 - 0.01) * self.t
        cos_theta[mask] = hard_example * (self.t + hard_example)
        cos_theta.scatter_(1, targets.view(-1, 1).long(), final_target_logit)
        pred_class_logits = cos_theta * self.s
        return pred_class_logits
 

Member Data Documentation

_num_classes

fastreid.layers.arc_softmax.ArcSoftmax._num_classes

protected

Definition at line 19 of file arc_softmax.py.

cos_m

fastreid.layers.arc_softmax.ArcSoftmax.cos_m

Definition at line 23 of file arc_softmax.py.

in_feat

fastreid.layers.arc_softmax.ArcSoftmax.in_feat

Definition at line 18 of file arc_softmax.py.

m

fastreid.layers.arc_softmax.ArcSoftmax.m

Definition at line 21 of file arc_softmax.py.

mm

fastreid.layers.arc_softmax.ArcSoftmax.mm

Definition at line 26 of file arc_softmax.py.

s

fastreid.layers.arc_softmax.ArcSoftmax.s

Definition at line 20 of file arc_softmax.py.

sin_m

fastreid.layers.arc_softmax.ArcSoftmax.sin_m

Definition at line 24 of file arc_softmax.py.

t

fastreid.layers.arc_softmax.ArcSoftmax.t

Definition at line 46 of file arc_softmax.py.

threshold

fastreid.layers.arc_softmax.ArcSoftmax.threshold

Definition at line 25 of file arc_softmax.py.

weight

fastreid.layers.arc_softmax.ArcSoftmax.weight

Definition at line 28 of file arc_softmax.py.

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The documentation for this class was generated from the following file:

• smreid/fastreid/layers/arc_softmax.py