Add a post-processor to compute the relative difference between 2 post-processors

[joshuahansel]

Rationale

It is useful to be to able to test that 2 post-processor values are relatively equal; this can be achieved by computing the relative difference between them and comparing to a tolerance. For instance, a test might output this relative difference value to a CSV file and then use the CSVDiff tester with abs_zero = my_relative_tol and rel_tol = 0.

Description

This adds a post-processor that computes the relative difference between 2 post-processor values.

Impact

This only adds a new post-processor; it does not affect any existing code.

[mangerij]

We have this. Look up PercentDifference post processor

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On Wed, Oct 25, 2017 at 9:55 PM joshuahansel ***@***.***> wrote: Rationale It is useful to be to able to test that 2 post-processor values are relatively equal; this can be achieved by computing the relative difference between them and comparing to a tolerance. For instance, a test might output this relative difference value to a CSV file and then use the CSVDiff tester with abs_zero = my_relative_tol and rel_tol = 0. Description This adds a post-processor that computes the relative difference between 2 post-processor values. Impact This only adds a new post-processor; it does not affect any existing code. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#10148>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AHPulGKoQitDTdprXaIk3CXORfQsI-z1ks5sv5IRgaJpZM4QGkST> .

[joshuahansel]

I do not see any PercentDifference post-processor. Could you tell me where this is located? The closest thing I see is PercentChangePostprocessor, but this is measuring the percent difference of a single post-processor between time steps, whereas I'm wanting to compute the percent difference between 2 post-processors for a given time level.

[mangerij]

My apologies. I read your PR wrong :) Carry on MOOSing!

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On Wed, Oct 25, 2017 at 10:08 PM joshuahansel ***@***.***> wrote: I do not see any PercentDifference post-processor. Could you tell me where this is located? The closest thing I see is PercentChangePostprocessor, but this is measuring the percent difference of a single post-processor between time steps, whereas I'm wanting to compute the percent difference between 2 post-processors for a given time level. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#10148 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AHPulC4n4OaAyrx4yWDI-ZFA1sqGzvxOks5sv5UwgaJpZM4QGkST> .