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Mathematica: Evaluation order during numerical optimisation of black box functions

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问题 I am attempting to perform a numerical optimisation of a "black box" function in Mathematica. Schematically it goes like this: NMinimize[{comb[x,y,z], x > 0}, {x,y,z}] where comb[x,y,z] is defined similarly to this: comb[x_,y_,z_] := Module[{}, Print[x,y,z]; M = FindMaximum[SkewNormal[a,x,y,z], {a,x}] // First; val = f[x,y,z,M]; Return[val]; ]; However, all of the minimisation functions I have tried seem to not immediately provide comb[x,y,z] with numerical values, and it ends up trying to

Equivalence Class Testing vs. Boundary Value Testing

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问题 I understand how equivalence testing works. How is it the same or different from boundary value testing? 回答1: Equivalence Class Testing EC Testing is when you have a number of test items (e.g. values) that you want to test but because of cost (time/money) you do not have time to test them all. Therefore you group the test item into class where all items in each class are suppose to behave exactly the same. The theory is that you only need to test one of each item to make sure the system works

Should I use “glass box” testing when it leads to fewer tests?

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问题 For example, I'm writing tests against a CsvReader. It's a simple class that enumerates and splits rows of text. Its only raison d'être is ignoring commas within quotes. It's less than a page. By "black box" testing the class, I've checked things like What if the file doesn't exist? What if I don't have permission on the file? What if the file has non-Windows line-breaks? But in fact, all of these things are the StreamReader's business. My class works without doing anything about these cases.

Mathematica: Evaluation order during numerical optimisation of black box functions

阅读更多关于 Mathematica: Evaluation order during numerical optimisation of black box functions

I am attempting to perform a numerical optimisation of a "black box" function in Mathematica. Schematically it goes like this: NMinimize[{comb[x,y,z], x > 0}, {x,y,z}] where comb[x,y,z] is defined similarly to this: comb[x_,y_,z_] := Module[{}, Print[x,y,z]; M = FindMaximum[SkewNormal[a,x,y,z], {a,x}] // First; val = f[x,y,z,M]; Return[val]; ]; However, all of the minimisation functions I have tried seem to not immediately provide comb[x,y,z] with numerical values, and it ends up trying to evaluate the FindMaximum with symbolic values for x,y,z (which is easily verified because the Print[x,y,z

Entity Framework SaveChanges - Customize Behavior?

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问题 So you instantiate an EF context, push objects in or pull objects out, it tracks the complete state of the object changes (if change tracking on). Up until this point the developer has been responsible for making these modifications. But once SaveChanges is called, all of these records are submitted in bulk and the developer is disenfranchised from the final result, save an error message on error or a successful call on completion. Is there a way to customize the SaveChanges process so that

Should QA test from a strictly black-box perspective?

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Assuming that unit tests are handled by development, is there any reason for QA to have knowledge of the details of how a product works? By which I mean, do they need to know what's going on in the background and should they test segments of a product without using the normal UI? For example, would it make sense for a tester to go into a database and manually change values to see what will happen? EDIT: Let's assume that we're working with an application to be used by non-developers, we're not working on something with an API attached. It depends on the approach and the kind of software you

Should QA test from a strictly black-box perspective?

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问题 Assuming that unit tests are handled by development, is there any reason for QA to have knowledge of the details of how a product works? By which I mean, do they need to know what's going on in the background and should they test segments of a product without using the normal UI? For example, would it make sense for a tester to go into a database and manually change values to see what will happen? EDIT: Let's assume that we're working with an application to be used by non-developers, we're

What's wrong with “magic”?

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I'm trying to decide whether to use a Rails or a Django guru to create a web app for me. I've been recommended to use Django because it uses less "magic". From my perspective however, the "magic" of Rails seems like a good thing since it could make development more concise for my contractor resulting in fewer billable hours at my expense. I understand the advantage of Django might be greater fine-grained control but how will I know if I need this control? Is there an inherent problem with "magic"? Well, consider a couple bits of Rails "magic": when you write a controller class, its methods

What's wrong with “magic”?

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问题 I'm trying to decide whether to use a Rails or a Django guru to create a web app for me. I've been recommended to use Django because it uses less "magic". From my perspective however, the "magic" of Rails seems like a good thing since it could make development more concise for my contractor resulting in fewer billable hours at my expense. I understand the advantage of Django might be greater fine-grained control but how will I know if I need this control? Is there an inherent problem with

Black box vs White box Testing

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Which type of testing would you say should be the emphasis (for testers/QAs), and why? A quick set of definitions from wikipedia: Black box testing takes an external perspective of the test object to derive test cases. These tests can be functional or non-functional, though usually functional. The test designer selects valid and invalid input and determines the correct output. There is no knowledge of the test object's internal structure. White box testing uses an internal perspective of the system to design test cases based on internal structure. It requires programming skills to identify all