Originally posted by: SecretName

Dear community, 

I'm trying to insert an exponential function into my model, but cplex doesn't solve it correctly. 

If I insert, for instance, x=3E2 it returns 300; if I insert x=3^2 it returns 1. 

What am I doing wrong? 

Furthermore, is Cplex able to calculate with negative exponents, which it uses from the dat.file? 

Thank you for your help in advance. 

Hi,

do you use a 32 or 64 bits cplex version ?

On my laptop

float x=3e2;
float x2=3^2;
float x3=2;

float y=exp(x);
float y2=exp(x2);
float y3=exp(x3);

float z=ln(y);
float z2=ln(y2);
float z3=ln(y3);

execute
{
y;
y2;
z;
z2;
z3;
writeln(z," ",z2," ",z3);
}

gives

300 9 2

which looks fine

regards

Originally posted by: SecretName

Hi Alex, 

Thanks for your quick answer. I use the 64 bit version. 

Another question: is it possible to use exp() if the variable has an array? 

Example:

float price[product]=...; (data from the dat.file)

float x=exp(price);

Thank you in advance!

Hi

float x[1..3]=[3e2,9,2];
    
    float y[i in 1..3]=exp(x[i]);

    float z[i in 1..3]=ln(y[i]);
     
     

    execute
    {
   
    writeln(z);
    }

gives

[300 9 2]

regards