Replies posted by Richard Stegeman

8 Replies

W
WRuijsscherExplorer
asked in AIMMS Developer

Question regarding the union of sets

I just create a new topic on the suggested set construction. Perhaps interesting to read.Filling a set via the union of its subsets | AIMMS Community

6
Richard Stegeman
Administrator
11 months ago
Richard Stegeman
Administrator
Richard StegemanAdministrator

Cases and runtime libraries

@sandervlot  I forgot to mention that if you do not want to include a runtime library in the saving of a case, then you should set the ‘NoSave’ property on the library when creating it. Like this:me::SetAttribute(myLib, 'Property', "NoSave");Unfortunately this does not always help when you read back an older case file that has the library already in. Especially if the runtime library is not yet present during case read (because AIMMS then doesn’t know about the ‘NoSave’ property).If from now on you will just work with 4.77, you can forget about the above.  

7682
Richard Stegeman
Administrator
1 year ago
B
bjorn94Newcomer
asked in AIMMS Developer

Why does the order of my set change?

Yes indeed, many of the more experienced AIMMS users work-around this problem by not using the fixed elements but instead use the StringToElement function. This moves the element-name-look-up from compile time to execution time, and that is what we also try to achieve in the current change that we make.  

5
Richard Stegeman
Administrator
1 year ago
B
bjorn94Newcomer
asked in AIMMS Developer

Why does the order of my set change?

This is indeed a rather unexpected ‘feature’ in AIMMS. Fixed quoted elements in the model text can have an effect on the ordering of elements in a set. Like in a statement elemParam := ‘elem1’;  or param(‘elem2’) := 3;If you really want a certain order in your set then use the order by attribute of the set. If you set this to ‘User’ then the assignments to the set will determine the set order (independent of any element being referenced somewhere else in the model text).In your example, I think that you can also make the set a subset of Integers. The problem with the ordering will then not be there.Perhaps good to know: at the moment we are working on this part of the compiler in AIMMS and we hope that this strange effect of fixed elements on the order of a set will be gone in the very near future. The ordering of the root sets (not a subset) in AIMMS will then by default behave like the ‘order by user’. 

5
Richard Stegeman
Administrator
1 year ago
afattahi
afattahiEnthusiast
asked in AIMMS Developer

How can I disable warnings of the Excel library (AXLL)

The recommended way to use the axll library is by placing all function calls in a block-onerror-endblock scope. In the onerror clause you can then catch each error or warning and decide what to with it. In this situation, check whether you are dealing with a warning (instead of error) and then call errh::markashandled() to make sure it is not propagated further.

2
Gertjan
AIMMSian
2 years ago
R
AIMMS Partner
RichardAIMMS Partner
posted in AIMMS Developer

.nch (namechange) file and version control

The .nch file is used in several parts of AIMMS: Indeed: for cases. The most relevant now-a-days where most applications are WebUI based. Via the .nch file AIMMS knows how to map old names that are stored in a case onto the new names in the model. In the WinUI, for all references to identifiers stored in pages and user menus. Sometimes for libraries, which were readonly at the time the name change was done. The best advice for handling the .nch file when multiple developers are working on the same model is: Before committing: do a ‘commit namechanges’ in your model. This assures that WinUI and all (non-readonly) libraries are up-to-date with the latest namechanges.  Check whether new entries in the name change file are relevant for any cases that may exist at the users of your model. For example, if the name changes only refer to newly created identifiers they are kind of redundant after the ‘commit namechanges’ command. If you have a conflict: try to preserve the time stamp order. Reg

4
sandervlot
AIMMS Partner
2 years ago
S
Stephen_PowickNewcomer
asked in AIMMS Developer

Error - A definition cannot as a side effect change another identifier

This is indeed no longer supported in AIMMS. A definition of an identifier is not allowed to change any other identifier. In earlier AIMMS versions the error was not given while it should, and thus the result could be undefined.  Just wondering why the definition needs the StringToElement. Is the following not doing the same? { (tpehis,pe) | FormatString("%e",pe) = SubString(FormatString("%e",tpehis),1,4) + "-" + SubString(FormatString("%e",tpehis),5,6) ,1)};

2
Richard Stegeman
Administrator
2 years ago
R
AIMMS Partner
RichardAIMMS Partner
asked in AIMMS Developer

How many rows to read from an excel file (axll)?

Somehow, we never got this question before. It does indeed sound like a very useful addition to the axll library. I checked the documentation of the third party library that AIMMS is using to implement the axll library and there are indeed functions to retrieve this information. We will add the following functions in one of the upcoming releases of AIMMS:  getLastUsedRow getLastUsedColumn and just to be complete: getFirstUsedRow getFirstUsedColumn (Update: released as of AIMMS 4.70.4!)

6
Mischa
AIMMSian
2 years ago
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