## Pass Variables from Java to MATLAB

### Ways to Pass Variables

You can pass Java® variables to MATLAB® using these methods:

• Pass the variables as function arguments in calls to the `MatlabEngine` `feval` and `fevalAsync` methods. Variables passed as arguments to function calls are not stored in the MATLAB base workspace.

• Put the variables in the MATLAB base workspace using the `MatlabEngine` `putVairable` and `putVariableAsync` methods.

For information on type conversions, see Java Data Type Conversions.

### Pass Function Arguments

This example code passes the coefficients of a polynomial, ${x}^{2}-x-6$, to the MATLAB `roots` function.

• Define a double array `p` to pass as an argument for the MATLAB `roots` function.

• Define a double array `r` to accept the returned values.

```import com.mathworks.engine.*; public class javaPassArg{ public static void main(String[] args) throws Exception{ MatlabEngine eng = MatlabEngine.startMatlab(); double[] p = {1.0, -1.0, -6.0}; double[] r = eng.feval("roots", p); for (double e: r) { System.out.println(e); } eng.close(); } }```

### Put Variables in the MATLAB Workspace

This example code puts variables in the MATLAB workspace and uses those variables as arguments in a MATLAB call to the MATLAB `complex` function. The MATLAB `who` command lists the workspace variables.

```import com.mathworks.engine.*; import java.util.Arrays; public class javaPutVar { public static void main(String[] args) throws Exception { MatlabEngine eng = MatlabEngine.startMatlab(); eng.putVariable("x", 7.0); eng.putVariable("y", 3.0); eng.eval("z = complex(x, y);"); String[] w = eng.feval("who"); System.out.println("MATLAB workspace variables " + Arrays.toString(w)); eng.close(); } }```

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