测量快速执行的测试代码
对于执行速度太快以至于 MATLAB® 不能准确测量的性能测试,将通过假设失败将其滤除。使用 keepMeasuring
方法,测试框架可以通过自动确定代码迭代次数并测量平均性能来显著加快代码测量速度。
在您的当前工作文件夹中创建一个基于类的测试,PreallocationTest.m
,用于对不同的预分配方法进行比较。由于测试方法中包括鉴定,因此可以使用 startMeasuring
和 stopMeasuring
方法来定义要测量的代码的边界。
classdef PreallocationTest < matlab.perftest.TestCase methods(Test) function testOnes(testCase) testCase.startMeasuring x = ones(1,1e5); testCase.stopMeasuring testCase.verifyEqual(size(x),[1 1e5]) end function testIndexingWithVariable(testCase) import matlab.unittest.constraints.IsSameSetAs testCase.startMeasuring id = 1:1e5; x(id) = 1; testCase.stopMeasuring testCase.verifyThat(x,IsSameSetAs(1)) end function testIndexingOnLHS(testCase) import matlab.unittest.constraints.EveryElementOf import matlab.unittest.constraints.IsEqualTo testCase.startMeasuring x(1:1e5) = 1; testCase.stopMeasuring testCase.verifyThat(EveryElementOf(x),IsEqualTo(1)) end function testForLoop(testCase) testCase.startMeasuring for i=1:1e5 x(i) = 1; end testCase.stopMeasuring testCase.verifyNumElements(x,1e5) end end end
运行 PreallocationTest
作为性能测试。滤除两个测试,因为测量结果太接近框架的精度。
results = runperf('PreallocationTest');
Running PreallocationTest ........ ================================================================================ PreallocationTest/testOnes was filtered. Test Diagnostic: The MeasuredTime should not be too close to the precision of the framework. Details ================================================================================ .. .......... .... ================================================================================ PreallocationTest/testIndexingOnLHS was filtered. Test Diagnostic: The MeasuredTime should not be too close to the precision of the framework. Details ================================================================================ ...... .. Done PreallocationTest __________ Failure Summary: Name Failed Incomplete Reason(s) ================================================================================== PreallocationTest/testOnes X Filtered by assumption. ---------------------------------------------------------------------------------- PreallocationTest/testIndexingOnLHS X Filtered by assumption.
要指示框架自动遍历已测量的代码并计算测量结果平均值,请修改 PreallocationTest
以使用 keepMeasuring-while
循环,而不是使用 startMeasuring
和 stopMeasuring
。
classdef PreallocationTest < matlab.perftest.TestCase methods(Test) function testOnes(testCase) while(testCase.keepMeasuring) x = ones(1,1e5); end testCase.verifyEqual(size(x),[1 1e5]) end function testIndexingWithVariable(testCase) import matlab.unittest.constraints.IsSameSetAs while(testCase.keepMeasuring) id = 1:1e5; x(id) = 1; end testCase.verifyThat(x,IsSameSetAs(1)) end function testIndexingOnLHS(testCase) import matlab.unittest.constraints.EveryElementOf import matlab.unittest.constraints.IsEqualTo while(testCase.keepMeasuring) x(1:1e5) = 1; end testCase.verifyThat(EveryElementOf(x),IsEqualTo(1)) end function testForLoop(testCase) while(testCase.keepMeasuring) for i=1:1e5 x(i) = 1; end end testCase.verifyNumElements(x,1e5) end end end
重新运行测试。所有测试全部完成。
results = runperf('PreallocationTest');
Running PreallocationTest .......... .......... .......... .. Done PreallocationTest __________
查看结果。
sampleSummary(results)
ans = 4×7 table Name SampleSize Mean StandardDeviation Min Median Max __________________________________________ __________ __________ _________________ __________ __________ __________ PreallocationTest/testOnes 4 3.0804e-05 1.8337e-07 3.0577e-05 3.0843e-05 3.0953e-05 PreallocationTest/testIndexingWithVariable 4 0.00044536 1.7788e-05 0.00042912 0.00044396 0.00046441 PreallocationTest/testIndexingOnLHS 4 5.6352e-05 1.8863e-06 5.5108e-05 5.5598e-05 5.9102e-05 PreallocationTest/testForLoop 4 0.0097656 0.00018202 0.0096181 0.0097065 0.010031