using dvar int in cumulFunction

Question

I have defined variables Itvs[units][activities][results] as intervals and resAlloc as an integer. The value of resAlloc influences the size of each interval in Itvs. However, when attempting to calculate the total resources allocated to each day using cumulFunction-pulse, I encounter a limitation because resAlloc is declared as a decision variable (dvar), which cannot be directly processed in this context.

int reqRes [u in units][i in activities][r in resources] = sum (t in unitTypes) unitConfig [u][t] * resInAct [t][i][r];
 
 dvar interval resItvs [units][activities][resources] optional;
 dvar int+ allocRes [units][activities][resources];
 
 
 dexpr int resDuration [u in units][i in activities][r in resources] = (reqRes[u][i][r] != 0) ? reqRes[u][i][r] div allocRes[u][i][r]: 0;
 cumulFunction resUsage [r in resources] = 
    sum(u in units, i in activities) pulse(resItvs[u][i][r], allocRes[u][i][r]);

I aim to utilize a cumulative function resUsage that adheres to the constraints imposed by resource availability.

forall (r in resources) resUsage [u] <= resAvail [r]

There might be alternative methods available apart from using pulse or cumulFunction. Thanks.

Alex Fleischer · Accepted Answer · 2024-05-07 12:03:32Z

0

You can use alternative to do the multiplication.

using CP;

range r=1..5;

dvar interval it;



dvar interval it_alternatives[r] optional;
cumulFunction c=sum(i in r)pulse(it_alternatives[i],10*i);

dvar int x in r;

maximize x;

subject to
{
 alternative(it,it_alternatives);
 startOf(it)==2;
 endOf(it)==4;
 c<=30;
 x==sum(i in r) (i*presenceOf(it_alternatives[i]));
}

int v[i in 0..5]=cumulFunctionValue(c,i);
execute
{
  writeln(v);
  writeln(x);
}

gives

[0 0 30 30 0 0]
3

answered May 7, 2024 at 12:03

Alex Fleischer

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