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Evaluating MATLAB Statements

You can evaluate MATLAB^® statements from Java^® using the MatlabEngine eval and evalAsync methods. These methods are similar to the MATLAB eval function. However, the eval and evalAsync methods do not return the results of evaluating the MATLAB statement.

You can also use the MatlabEngine feval and fevalAsync methods to call MATLAB functions. These methods enable you to pass variables to the MATLAB workspace and return values to Java.

The input arguments named in the string must exist in the MATLAB workspace. You can assign the results of the evaluation to variables within the statement string. The variable names that you assign in the statement are created in the MATLAB base workspace. MATLAB does not require you to initialize the variables created in the expression.

To return the variables created in the MATLAB workspace, use the MatlabEngine getVariable or getVariableAsync methods.

Evaluate Mathematical Function in MATLAB

This example code evaluates a mathematical function over a specified domain using two MATLAB statements. The meshgrid function creates MATLAB variables X, Y, and Z in the MATLAB workspace. These variables are used by the mathematical expression in the next call to evalAsync.

The MatlabEngine getVariable method returns the result of the evaluation to Java.

import com.mathworks.engine.*;

public class javaEvalFunc {
    public static void main(String[] args) throws Exception {
        MatlabEngine eng = MatlabEngine.startMatlab();
        eng.evalAsync("[X, Y] = meshgrid(-2:0.2:2);");
        eng.evalAsync("Z = X .* exp(-X.^2 - Y.^2);");
        Object[] Z = eng.getVariable("Z");
        eng.close();
        }
}