## Syntax help with Example 5.6 Migration to OPTMODEL: Generalized Networks

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# Syntax help with Example 5.6 Migration to OPTMODEL: Generalized Networks

Hello,

where can I find documentation regarding the "()"-brackets as in the node balancing restriction of example 5.6 (SAS/OR(R) 9.3 User's Guide: Mathematical Programming)?

con balance {i in NODES}:

sum {<(i),j> in ARCS} Flow[i,j]

- sum {<j,(i)> in ARCS} Flow[j,i]

= _sd_;

Why this is necessary is quite clear; but can't find anything on this optmodel syntax.

Thanks & kind regards

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Solution
‎04-10-2015 09:45 AM
SAS Employee
Posts: 538

## Re: Syntax help with Example 5.6 Migration to OPTMODEL: Generalized Networks

It is discussed in the "More on Index Sets" section of the PROC OPTMODEL documentation:

SAS/OR(R) 13.2 User's Guide: Mathematical Programming

SAS/OR(R) 13.2 User's Guide: Mathematical Programming Examples

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Solution
‎04-10-2015 09:45 AM
SAS Employee
Posts: 538

## Re: Syntax help with Example 5.6 Migration to OPTMODEL: Generalized Networks

It is discussed in the "More on Index Sets" section of the PROC OPTMODEL documentation:

SAS/OR(R) 13.2 User's Guide: Mathematical Programming

SAS/OR(R) 13.2 User's Guide: Mathematical Programming Examples

SAS Employee
Posts: 37

## Re: Syntax help with Example 5.6 Migration to OPTMODEL: Generalized Networks

It is a shorthand for the slice operator, often used to make this very common pattern:

sum{<i,j> in FOO: i = something} x[i,j]

shorter, as in:

sum{<(something),j> in FOO} x[something,j]

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