vnpy/docs/cta_backtester.md
2019-05-08 22:18:56 +08:00

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# CTA回测模块
CTA回测模块是基于PyQt5和pyqtgraph的图形化回测工具。启动VN Trader后在菜单栏中点击“功能-> CTA回测”即可进入该图形化回测界面如下图。CTA回测模块主要实现3个功能历史行情数据的下载、策略回测、参数优化。
![](https://vnpy-community.oss-cn-shanghai.aliyuncs.com/forum_experience/yazhang/cta_backtester/cta_backtester.png)
 
## 加载启动
进入图形化回测界面“CTA回测”后会立刻完成初始化工作初始化回测引擎、初始化RQData客户端。
```
def init_engine(self):
""""""
self.write_log("初始化CTA回测引擎")
self.backtesting_engine = BacktestingEngine()
# Redirect log from backtesting engine outside.
self.backtesting_engine.output = self.write_log
self.write_log("策略文件加载完成")
self.init_rqdata()
def init_rqdata(self):
"""
Init RQData client.
"""
result = rqdata_client.init()
if result:
self.write_log("RQData数据接口初始化成功")
```
 
## 下载数据
在开始策略回测之前必须保证数据库内有充足的历史数据。故vnpy提供了历史数据一键下载的功能。
下载数据功能主要是基于RQData的get_price()函数实现的。
```
get_price(
order_book_ids, start_date='2013-01-04', end_date='2014-01-04',
frequency='1d', fields=None, adjust_type='pre', skip_suspended =False,
market='cn'
)
```
在使用前要保证RQData初始化完毕然后填写以下4个字段信息
- 本地代码:格式为合约品种+交易所如IF88.CFFEX、rb88.SHFE然后在底层通过RqdataClient的to_rq_symbol()函数转换成符合RQData格式对应RQData中get_price()函数的order_book_ids字段。
- K线周期可以填1m、60m、1d对应get_price()函数的frequency字段。
- 开始日期格式为yy/mm/dd如2017/4/21对应get_price()函数的start_date字段。点击窗口右侧箭头按钮可改变日期大小
- 结束日期格式为yy/mm/dd如2019/4/22对应get_price()函数的end_date字段。点击窗口右侧箭头按钮可改变日期大小
填写完字段信息后,点击下方“下载数据”按钮启动下载程序,下载成功如图所示。
![](https://vnpy-community.oss-cn-shanghai.aliyuncs.com/forum_experience/yazhang/cta_backtester/data_loader.png)
 
## 策略回测
下载完历史数据后,需要配置以下字段:交易策略、手续费率、交易滑点、合约乘数、价格跳动、回测资金。
这些字段主要对应BacktesterEngine类的run_backtesting函数。
```
def run_backtesting(
self, class_name: str, vt_symbol: str, interval: str, start: datetime,
end: datetime, rate: float, slippage: float, size: int, pricetick: float,
capital: int, setting: dict
)
```
点击下方的“开始回测”按钮可以开始回测:
首先会弹出如图所示的参数配置窗口用于调整策略参数。该设置对应的是run_backtesting()函数的setting字典。
![](https://vnpy-community.oss-cn-shanghai.aliyuncs.com/forum_experience/yazhang/cta_backtester/parameter_setting.png)
点击“确认”按钮后开始运行回测,同时日志界面会输出相关信息,如图。
![](https://vnpy-community.oss-cn-shanghai.aliyuncs.com/forum_experience/yazhang/cta_backtester/backtesting_log.png)
回测完成后会显示统计数字图表。
 
### 统计数据
用于显示回测完成后的相关统计数值, 如结束资金、总收益率、夏普比率、收益回撤比。
![](https://vnpy-community.oss-cn-shanghai.aliyuncs.com/forum_experience/yazhang/cta_backtester/show_result.png)
 
### 图表分析
以下四个图分别是代表账号净值、净值回撤、每日盈亏、盈亏分布。
![](https://vnpy-community.oss-cn-shanghai.aliyuncs.com/forum_experience/yazhang/cta_backtester/show_result_chat.png)
 
## 参数优化
vnpy提供2种参数优化的解决方案穷举算法、遗传算法
 
### 穷举算法
穷举算法原理:
- 输入需要优化的参数名、优化区间、优化步进,以及优化目标。
```
def add_parameter(
self, name: str, start: float, end: float = None, step: float = None
):
""""""
if not end and not step:
self.params[name] = [start]
return
if start >= end:
print("参数优化起始点必须小于终止点")
return
if step <= 0:
print("参数优化步进必须大于0")
return
value = start
value_list = []
while value <= end:
value_list.append(value)
value += step
self.params[name] = value_list
def set_target(self, target_name: str):
""""""
self.target_name = target_name
```
&nbsp;
- 形成全局参数组合, 数据结构为[{key: value, key: value}, {key: value, key: value}]。
```
def generate_setting(self):
""""""
keys = self.params.keys()
values = self.params.values()
products = list(product(*values))
settings = []
for p in products:
setting = dict(zip(keys, p))
settings.append(setting)
return settings
```
&nbsp;
- 遍历全局中的每一个参数组合:遍历的过程即运行一次策略回测,并且返回优化目标数值;然后根据目标数值排序,输出优化结果。
```
def run_optimization(self, optimization_setting: OptimizationSetting, output=True):
""""""
# Get optimization setting and target
settings = optimization_setting.generate_setting()
target_name = optimization_setting.target_name
if not settings:
self.output("优化参数组合为空,请检查")
return
if not target_name:
self.output("优化目标未设置,请检查")
return
# Use multiprocessing pool for running backtesting with different setting
pool = multiprocessing.Pool(multiprocessing.cpu_count())
results = []
for setting in settings:
result = (pool.apply_async(optimize, (
target_name,
self.strategy_class,
setting,
self.vt_symbol,
self.interval,
self.start,
self.rate,
self.slippage,
self.size,
self.pricetick,
self.capital,
self.end,
self.mode
)))
results.append(result)
pool.close()
pool.join()
# Sort results and output
result_values = [result.get() for result in results]
result_values.sort(reverse=True, key=lambda result: result[1])
if output:
for value in result_values:
msg = f"参数:{value[0]}, 目标:{value[1]}"
self.output(msg)
return result_values
```
注意可以使用multiprocessing库来创建多进程实现并行优化。例如若用户计算机是2核优化时间为原来1/2若计算机是10核优化时间为原来1/10。
&nbsp;
穷举算法操作:
- 点击“参数优化”按钮,会弹出“优化参数配置”窗口,用于设置优化目标(如最大化夏普比率、最大化收益回撤比)和设置需要优化的参数以及优化区间,如图。
![](https://vnpy-community.oss-cn-shanghai.aliyuncs.com/forum_experience/yazhang/cta_backtester/optimize_setting.png)
- 设置好需要优化的参数后点击“优化参数配置”窗口下方的“确认”按钮开始进行调用CPU多核进行多进程并行优化同时日志会输出相关信息。
![](https://vnpy-community.oss-cn-shanghai.aliyuncs.com/forum_experience/yazhang/cta_backtester/optimize_log.png)
- 点击“优化结果”按钮可以看出优化结果,如图的参数组合是基于目标数值(夏普比率)由高到低的顺序排列的。
![](https://vnpy-community.oss-cn-shanghai.aliyuncs.com/forum_experience/yazhang/cta_backtester/optimize_result.png)
&nbsp;
### 遗传算法
遗传算法原理:
- 输入需要优化的参数名、优化区间、优化步进,以及优化目标;
- 形成全局参数组合,该组合的数据结构是列表内镶嵌元组,即[[(key, value), (key, value)] , [(key, value), (key,value)]],与穷举算法的全局参数组合的数据结构不同。这样做的目的是有利于参数间进行交叉互换和变异。
```
def generate_setting_ga(self):
""""""
settings_ga = []
settings = self.generate_setting()
for d in settings:
param = [tuple(i) for i in d.items()]
settings_ga.append(param)
return settings_ga
```
&nbsp;
- 形成个体调用random()函数随机从全局参数组合中获取参数。
```
def generate_parameter():
""""""
return random.choice(settings)
```
&nbsp;
- 定义个体变异规则: 即发生变异时,旧的个体完全被新的个体替代。
```
def mutate_individual(individual, indpb):
""""""
size = len(individual)
paramlist = generate_parameter()
for i in range(size):
if random.random() < indpb:
individual[i] = paramlist[i]
return individual,
```
&nbsp;
- 定义评估函数:入参的是个体,即[(key, value), (key, value)]形式的参数组合然后通过dict()转化成setting字典然后运行回测输出目标优化数值如夏普比率、收益回撤比。(注意,修饰器@lru_cache作用是缓存计算结果避免遇到相同的输入重复计算大大降低运行遗传算法的时间)
```
@lru_cache(maxsize=1000000)
def _ga_optimize(parameter_values: tuple):
""""""
setting = dict(parameter_values)
result = optimize(
ga_target_name,
ga_strategy_class,
setting,
ga_vt_symbol,
ga_interval,
ga_start,
ga_rate,
ga_slippage,
ga_size,
ga_pricetick,
ga_capital,
ga_end,
ga_mode
)
return (result[1],)
def ga_optimize(parameter_values: list):
""""""
return _ga_optimize(tuple(parameter_values))
```
&nbsp;
- 运行遗传算法调用deap库的算法引擎来运行遗传算法其具体流程如下。
1先定义优化方向如夏普比率最大化
2然后随机从全局参数组合获取个体并形成族群
3对族群内所有个体进行评估即运行回测并且剔除表现不好个体
4剩下的个体会进行交叉或者变异通过评估和筛选后形成新的族群到此为止是完整的一次种群迭代过程
5多次迭代后种群内差异性减少整体适应性提高最终输出建议结果。该结果为帕累托解集可以是1个或者多个参数组合。
注意:由于用到了@lru_cache, 迭代中后期的速度回提高非常多,因为很多重复的输入都避免了再次的回测,直接在内存中查询并且返回计算结果。
```
from deap import creator, base, tools, algorithms
creator.create("FitnessMax", base.Fitness, weights=(1.0,))
creator.create("Individual", list, fitness=creator.FitnessMax)
......
# Set up genetic algorithem
toolbox = base.Toolbox()
toolbox.register("individual", tools.initIterate, creator.Individual, generate_parameter)
toolbox.register("population", tools.initRepeat, list, toolbox.individual)
toolbox.register("mate", tools.cxTwoPoint)
toolbox.register("mutate", mutate_individual, indpb=1)
toolbox.register("evaluate", ga_optimize)
toolbox.register("select", tools.selNSGA2)
total_size = len(settings)
pop_size = population_size # number of individuals in each generation
lambda_ = pop_size # number of children to produce at each generation
mu = int(pop_size * 0.8) # number of individuals to select for the next generation
cxpb = 0.95 # probability that an offspring is produced by crossover
mutpb = 1 - cxpb # probability that an offspring is produced by mutation
ngen = ngen_size # number of generation
pop = toolbox.population(pop_size)
hof = tools.ParetoFront() # end result of pareto front
stats = tools.Statistics(lambda ind: ind.fitness.values)
np.set_printoptions(suppress=True)
stats.register("mean", np.mean, axis=0)
stats.register("std", np.std, axis=0)
stats.register("min", np.min, axis=0)
stats.register("max", np.max, axis=0)
algorithms.eaMuPlusLambda(
pop,
toolbox,
mu,
lambda_,
cxpb,
mutpb,
ngen,
stats,
halloffame=hof
)
# Return result list
results = []
for parameter_values in hof:
setting = dict(parameter_values)
target_value = ga_optimize(parameter_values)[0]
results.append((setting, target_value, {}))
return results
```