operator design #2555
operator design #2555
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jacquesqiao
assigned reyoung, JiayiFeng, QiJune and jacquesqiao and unassigned reyoung, JiayiFeng and QiJune
doc/design/operator.md
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| namespace framework { | ||
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| template <class DeviceContext> | ||
| class Operator { |
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我们的Operator需要几层来去定义呢？
caffe2的做法是三层：
第一层是OperatorBase，用来做类型擦除
class OperatorBase
第二层是模板类Operator
template <typename Context>
class Operator
第三层是具体的实现
template <typename T, typename Context>
class ReluOp final : Operator<Context>
之所以Caffe2是三层设计，因为在Operator里面有一个成员变量device_context_，但目前看起来这个变量并没有什么作用。
或许在这里只需要两层设计：
第一层，OperatorBase作为类型擦除
class OperatorBase {
bool Run(Scope* scope) final {
return RunOnDevice();
}
virtual bool RunOnDevice() = 0;
protected:
vector<string*> inputs_;
vector<string*> outputs_;
};
第二层为具体的实现：
template <typename T, typename Context>
class ReluOp : final OperatorBase {
};
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Context 这个概念是不是需要专门看一下，来帮助我们理解如何正确的设计Op
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是的，我觉得需要再看一下
如果我们需要的仅仅是表示一个Op是CPU/GPU设备上，那么简单的 class Device就行了；
如果需要在不同设备上有些特殊操作之类的，那么可能会需要一个略为复杂的class Context
doc/design/operator.md
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| }; | ||
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| // Operator is the class your should derive when implement a new Operator. | ||
| template <typename T> |
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Maybe rename T-> DeviceContext is better.
doc/design/operator.md
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| explicit Operator(const OperatorDesc& desc): OperatorBase(desc) {} | ||
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| // This function will | ||
| Error Run(Scope* scope, T* context) const final {} |
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Please give a pseudo implementation here
doc/design/operator.md
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| Error Run(Scope* scope, T* context) const final {} | ||
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| // when implement an Op, your should implement this function. | ||
| virtual Error Run(std::vector<Variable> inputs, |
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const std::vector<const Variable*>& inputs, const std::vector<Variable*>& outputs
| `OperatorBase` cantains the base element of an Operator, but without any specialized information. The reason is that Net can treat all Ops as OperatorBase and donot need to consider the type or context of these ops. It can just call run() of Op: | ||
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| ```cpp | ||
| class Net { |
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Net => NetworkBase for consistent to Network design
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| #### `OperatorBase` | ||
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| `OperatorBase` cantains the base element of an Operator, but without any specialized information. The reason is that Net can treat all Ops as OperatorBase and donot need to consider the type or context of these ops. It can just call run() of Op: |
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contains --> is a base class of an Operator
base element --> base class
cantains --> contains
specialized --> specific
The reason is that --> because
Net --> NetworkBase
donot --> do not
run --> Run
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| `Operator` has a template parameter `DeviceContext`. DeviceContext is used to specify on which device this op will run. Each Op will implement multi Op according to different Context. | ||
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| #### We design the Operator class with tree layer. |
| if (scale_ <= 0.0f) { | ||
| return Error("Scale of cosine op should be larger than 0.0"); | ||
| } | ||
| return Error(); // OK; |
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rename Error -> Status better ?
It's wired that Error() means ok, and Error(xxx) means a real error.
refs:
Design doc for operator attribute(#2606)