Originally posted by: deepalcoholic

.mod file
int n = 10;
range s = 1..n;
int a[s] = 0,10,20,30,40,0,60,70,80,90;

{int} b = {w|w in s:a[w]^2 <= 10000};

execute
{
writeln(b);
}

When I run the mode file above, the b set I get is empty?
But when I replace {int} b = {w|w in s:a[w]^2 <= 10000}; by
{int} b = {w|w in s:a[w]^2 >= 100}; the "b" set I get is not empty.
I need help to solve the above problem?
Thank you!
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Hi

for b I get

{1 2 3 4 5 6 7 8 9 10}

Which version do you use?

Regards
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Originally posted by: deepalcoholic

i use 12.3 academic
what version do u use?
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Hi

I also use CPLEX 12.3
Can you attach a screenshot?
We should have the same results.

Regards
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Originally posted by: deepalcoholic

hi,this is my test
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Originally posted by: deepalcoholic

Hi,this is my result
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Originally posted by: SystemAdmin

Hi,

the code

int n = 10;
range s = 1..n;
int a[s] = [0,10,20,30,40,0,60,70,80,90];
 
{int} b = {w|w in s:a[w]^2 <= 10000};
{int} c = {w|w in s:a[w]*a[w] <= 10000};
 
execute
{
writeln("b=",b);
writeln("c=",c);
}

results in

b= {}
c= {1 2 3 4 5 6 7 8 9 10}

As far as I remember the operator '^2' does not correspond
to the expected 'squared' operator, but to some bit-operation
('exclusive or').

Regards
Norbert
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Originally posted by: SystemAdmin

Hi,

the code

int n = 10;
range s = 1..n;
int a[s] = [0,10,20,30,40,0,60,70,80,90];
 
{int} b = {w|w in s:a[w]^2 <= 10000};
{int} c = {w|w in s:a[w]*a[w] <= 10000};
 
execute
{
writeln("b=",b);
writeln("c=",c);
}

results in

b= {}
c= {1 2 3 4 5 6 7 8 9 10}

As far as I remember the operator '^2' does not correspond
to the expected 'squared' operator, but to some bit-operation
('exclusive or').

Regards
Norbert
#DecisionOptimization
#OPLusingCPLEXOptimizer

Originally posted by: deepalcoholic

Thank you for your answer.

but AlexFleischer said he can get the result using ^,I don't know why?

not just ^,but also the function pow() and sqrt() doesn't work either
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Originally posted by: SystemAdmin

The behaviour of '^2' is somewhat expected from the javascript definition.

But I agree - the behaviour of pow() is strange ...

{int} d = {w|w in s: pow(a[w],2) <= 10000};
float x = pow(a[2],2);
 
execute
{
  writeln("x = ", x);
  writeln("d=",d);
}

results in

x = 100
d= {}

Regards
Norbert
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Originally posted by: SystemAdmin

It must be a problem with the evaluation of the condition for which the set is constructed, as the following code works:

float powa[w in s] = pow(a[w],2);
{int} e = {w|w in s: powa[w] <= 10000.0};
execute
{
  writeln("powa = ", powa);
  writeln("e=",e);
}

results in

powa =  [0 100 400 900 1600 0 3600 4900 6400 8100]
e= {1 2 3 4 5 6 7 8 9 10}

Regards
Norbert
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Originally posted by: SystemAdmin

Thank you for bringing this to our notice. I have let the developers know about the behavior. In the meanwhile, please continue to use the format that works.
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