/* package whatever; // don't place package name! */
import java.util.*;
import java.lang.*;
import java.math.*;
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
{
double A= -0.5,B=-0.4,C=7, X0=0.3, Y0=0.2;
double X0Y0
= Math.
pow(X0
-A,
2) + Math.
pow(Y0
-B,
2) + C
*Math.
exp(-(Math.
pow(X0
+A,
2))-Math.
pow(Y0
+B,
2)); double X1Y0
= Math.
pow(X0
+0.1-A,
2) + Math.
pow(Y0
-B,
2) + C
*Math.
exp(-(Math.
pow(X0
+0.1+A,
2))-Math.
pow(Y0
+B,
2)); double X0Y1
= Math.
pow(X0
-A,
2) + Math.
pow(Y0
+0.1-B,
2) + C
*Math.
exp(-(Math.
pow(X0
+A,
2))-Math.
pow(Y0
+0.1+B,
2));
double gx=(X1Y0-X0Y0)/0.1;
double gy=(X0Y1-X0Y0)/0.1;
double rez
=Math.
atan2(gy, gx
);
}
}
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