From 04ad9b6b02f0ca69c6b8b879397906edf1fec61f Mon Sep 17 00:00:00 2001 From: Yu Yang Date: Thu, 22 Jun 2017 15:10:37 +0800 Subject: [PATCH 1/4] Add Scope Parent & Local section --- doc/design/scope.md | 31 +++++++++++++++++++++++++++---- 1 file changed, 27 insertions(+), 4 deletions(-) diff --git a/doc/design/scope.md b/doc/design/scope.md index e73d3c231c..3ebbd26338 100644 --- a/doc/design/scope.md +++ b/doc/design/scope.md @@ -17,11 +17,34 @@ * 每一个Scope析构的时候，会同时析构variable * 只能通过Scope创建Vairable。 * 只能通过Scope获取Variable。 -## Scope 可以被继承或者叫共享 -解释下Scope如何被共享，如何查找Variable的算法。 - * Scope永远从本地寻找Variable，找不到会从他的父亲Scope寻找Variable - * 嵌套深度不做要求。 +## Parent scope and local scope + +Just like [scope](https://en.wikipedia.org/wiki/Scope_(computer_science)) in programming languages, `Scope` in the neural network also can be local. There are two attributes about local scope. + +* We can create local variables in a local scope, and when that local scope are destroyed, all local variables should also be destroyed. +* Variables in a parent scope can be retrieved from that parent scope's local scope, i.e., when user get a variable from a scope, it will search this variable in current scope firstly. If there is no such variable in local scope, `scope` will keep searching from its parent, until the variable is found or there is no parent. + +```cpp +class Scope { +public: + Scope(const std::shared_ptr& scope): parent_(scope) {} + + Variable* Get(const std::string& name) const { + Variable* var = GetVarLocally(name); + if (var != nullptr) { + return var; + } else if (parent_ != nullptr) { + return parent_->Get(name); + } else { + return nullptr; + } + } + +private: + std::shared_ptr parent_ {nullptr}; +}; +``` # 接口实现 From 581e4c1cbd2208896dbbc6facef4099a607bfc8c Mon Sep 17 00:00:00 2001 From: Yu Yang Date: Thu, 22 Jun 2017 15:27:16 +0800 Subject: [PATCH 2/4] Parent & local scope done --- doc/design/scope.md | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/doc/design/scope.md b/doc/design/scope.md index 3ebbd26338..27ceed961f 100644 --- a/doc/design/scope.md +++ b/doc/design/scope.md @@ -20,10 +20,10 @@ ## Parent scope and local scope -Just like [scope](https://en.wikipedia.org/wiki/Scope_(computer_science)) in programming languages, `Scope` in the neural network also can be local. There are two attributes about local scope. +Just like [scope](https://en.wikipedia.org/wiki/Scope_(computer_science)) in programming languages, `Scope` in the neural network also can be local. There are two attributes about local scope. -* We can create local variables in a local scope, and when that local scope are destroyed, all local variables should also be destroyed. -* Variables in a parent scope can be retrieved from that parent scope's local scope, i.e., when user get a variable from a scope, it will search this variable in current scope firstly. If there is no such variable in local scope, `scope` will keep searching from its parent, until the variable is found or there is no parent. +1. We can create local variables in a local scope, and when that local scope are destroyed, all local variables should also be destroyed. +2. Variables in a parent scope can be retrieved from that parent scope's local scope, i.e., when user get a variable from a scope, it will search this variable in current scope firstly. If there is no such variable in local scope, `scope` will keep searching from its parent, until the variable is found or there is no parent. ```cpp class Scope { @@ -46,6 +46,10 @@ private: }; ``` +In `Scope` class, there is a private data member called `parent_`. `parent_` is a smart pointer to its parent scope. When user `Get` a variable by its `name`, the `name` will be searched locally inside the current scope. If the variable cannot be found locally and parent scope is not a `nullptr`, the variable will be searched inside that parent scope. `parent_` pointer's default value is `nullptr`. It means that the scope is a global scope when `parent_` is nullptr. + +A local scope is very useful when we implement Recurrent Neural Network. Each timestep of an RNN should be a `Net`. Each `Net` of timestep (`StepNet` for short) should use an independent local scope. Just like each variable in a while loop is inside a local scope in programming languages. By using a single `StepNet` and changing local scope, we can implement an RNN easily. + # 接口实现 # 各个接口是啥意思，为啥这么设计 From 0b70361a0ee71ed04ca6925a25bbdd3e434c2bfe Mon Sep 17 00:00:00 2001 From: Yu Yang Date: Thu, 22 Jun 2017 15:35:00 +0800 Subject: [PATCH 3/4] Refining english --- doc/design/scope.md | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/doc/design/scope.md b/doc/design/scope.md index 27ceed961f..341ec16d79 100644 --- a/doc/design/scope.md +++ b/doc/design/scope.md @@ -20,10 +20,10 @@ ## Parent scope and local scope -Just like [scope](https://en.wikipedia.org/wiki/Scope_(computer_science)) in programming languages, `Scope` in the neural network also can be local. There are two attributes about local scope. +Just like [scope](https://en.wikipedia.org/wiki/Scope_(computer_science)) in programming languages, `Scope` in the neural network can also be local. There are two attributes about local scope. -1. We can create local variables in a local scope, and when that local scope are destroyed, all local variables should also be destroyed. -2. Variables in a parent scope can be retrieved from that parent scope's local scope, i.e., when user get a variable from a scope, it will search this variable in current scope firstly. If there is no such variable in local scope, `scope` will keep searching from its parent, until the variable is found or there is no parent. +1. We can create local variables in a local scope. When that local scope are destroyed, all local variables should also be destroyed. +2. Variables in a parent scope can be retrieved from that parent scope's local scopes, i.e., when user get a variable from a scope, it will try to search this variable in current scope. If there is no such variable in the local scope, `scope` will keep searching from its parent, until the variable is found or there is no parent. ```cpp class Scope { @@ -46,9 +46,9 @@ private: }; ``` -In `Scope` class, there is a private data member called `parent_`. `parent_` is a smart pointer to its parent scope. When user `Get` a variable by its `name`, the `name` will be searched locally inside the current scope. If the variable cannot be found locally and parent scope is not a `nullptr`, the variable will be searched inside that parent scope. `parent_` pointer's default value is `nullptr`. It means that the scope is a global scope when `parent_` is nullptr. +In `Scope` class, there is a private data member called `parent_`. `parent_` is a smart pointer to its parent scope. When user `Get` a variable by its `name`, the `name` will be searched inside the current scope. If the variable cannot be found locally and parent scope is not a `nullptr`, the variable will be searched inside that parent scope. `parent_` pointer's default value is `nullptr`. It means that the scope is a global scope when `parent_` is nullptr. -A local scope is very useful when we implement Recurrent Neural Network. Each timestep of an RNN should be a `Net`. Each `Net` of timestep (`StepNet` for short) should use an independent local scope. Just like each variable in a while loop is inside a local scope in programming languages. By using a single `StepNet` and changing local scope, we can implement an RNN easily. +A local scope is very useful when we implement Recurrent Neural Network. Each timestep of an RNN should be a `Net`. Each `Net` of timestep (`StepNet` for short) should use an independent local scope. Just like variables in a while loop is inside a local scope in programming languages. By using a single `StepNet` and changing local scope, we can implement an RNN easily. # 接口实现 From 76e2a3cd95236ab29fb1b5562d5aab52afa99470 Mon Sep 17 00:00:00 2001 From: Yu Yang Date: Thu, 22 Jun 2017 15:40:08 +0800 Subject: [PATCH 4/4] Refine English --- doc/design/scope.md | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/doc/design/scope.md b/doc/design/scope.md index 341ec16d79..695426b2f2 100644 --- a/doc/design/scope.md +++ b/doc/design/scope.md @@ -20,10 +20,10 @@ ## Parent scope and local scope -Just like [scope](https://en.wikipedia.org/wiki/Scope_(computer_science)) in programming languages, `Scope` in the neural network can also be local. There are two attributes about local scope. +Just like [scope](https://en.wikipedia.org/wiki/Scope_(computer_science)) in programming languages, `Scope` in the neural network can also be a local scope. There are two attributes about local scope. 1. We can create local variables in a local scope. When that local scope are destroyed, all local variables should also be destroyed. -2. Variables in a parent scope can be retrieved from that parent scope's local scopes, i.e., when user get a variable from a scope, it will try to search this variable in current scope. If there is no such variable in the local scope, `scope` will keep searching from its parent, until the variable is found or there is no parent. +2. Variables in a parent scope can be retrieved from local scopes of that parent scope, i.e., when user get a variable from a scope, it will try to search this variable in current scope. If there is no such variable in the local scope, `scope` will keep searching from its parent, until the variable is found or there is no parent. ```cpp class Scope {