Example Customizing Equations - Revision history

Peter at 00:52, 19 May 2017

2017-05-19T00:52:13Z

Peter at 01:00, 10 August 2015

2015-08-10T01:00:59Z

Peter at 02:47, 1 April 2015

2015-04-01T02:47:36Z

Peter: Created page with "While Equations provides many of the most common functions used in Linear Algebra, there are many it does not provide. The following example demonstrates how to add your own..."

2015-03-22T06:16:12Z

Created page with "While Equations provides many of the most common functions used in Linear Algebra, there are many it does not provide. The following example demonstrates how to add your own..."

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While Equations provides many of the most common functions used in Linear Algebra, there are many it does not provide. The following example demonstrates how to add your own functions to Equations allowing you to extend its capabilities.

Code on GitHub:
* [https://github.com/lessthanoptimal/ejml/blob/master/examples/src/org/ejml/example/EquationCustomFunction.java EquationCustomFunction]

== Example ==

<syntaxhighlight lang="java">
/**
* Demonstration on how to create and use a custom function in Equation. A custom function must implement
* ManagerFunctions.Input1 or ManagerFunctions.InputN, depending on the number of inputs it takes.
*
* @author Peter Abeles
*/
public class EquationCustomFunction {

public static void main(String[] args) {
Random rand = new Random(234);

Equation eq = new Equation();
eq.getFunctions().add("multTransA",createMultTransA());

SimpleMatrix A = new SimpleMatrix(1,1); // will be resized
SimpleMatrix B = SimpleMatrix.random(3,4,-1,1,rand);
SimpleMatrix C = SimpleMatrix.random(3,4,-1,1,rand);

eq.alias(A,"A",B,"B",C,"C");

eq.process("A=multTransA(B,C)");

System.out.println("Found");
System.out.println(A);
System.out.println("Expected");
B.transpose().mult(C).print();
}

/**
* Create the function. Be sure to handle all possible input types and combinations correctly and provide
* meaningful error messages. The output matrix should be resized to fit the inputs.
*/
public static ManagerFunctions.InputN createMultTransA() {
return new ManagerFunctions.InputN() {
@Override
public Operation.Info create(List<Variable> inputs, ManagerTempVariables manager ) {
if( inputs.size() != 2 )
throw new RuntimeException("Two inputs required");

final Variable varA = inputs.get(0);
final Variable varB = inputs.get(1);

Operation.Info ret = new Operation.Info();

if( varA instanceof VariableMatrix && varB instanceof VariableMatrix ) {

// The output matrix or scalar variable must be created with the provided manager
final VariableMatrix output = manager.createMatrix();
ret.output = output;
ret.op = new Operation("multTransA-mm") {
@Override
public void process() {
DenseMatrix64F mA = ((VariableMatrix)varA).matrix;
DenseMatrix64F mB = ((VariableMatrix)varB).matrix;
output.matrix.reshape(mA.numCols,mB.numCols);

CommonOps.multTransA(mA,mB,output.matrix);
}
};
} else {
throw new IllegalArgumentException("Expected both inputs to be a matrix");
}

return ret;
}
};
}
}
</syntaxhighlight>

@@ Line 2: / Line 2: @@
 External Resources:
-* [https://github.com/lessthanoptimal/ejml/blob/v0.27/examples/src/org/ejml/example/EquationCustomFunction.java EquationCustomFunction.java source code]
+* [https://github.com/lessthanoptimal/ejml/blob/v0.31/examples/src/org/ejml/example/EquationCustomFunction.java EquationCustomFunction.java source code]
 * <disqus>Discuss this example</disqus>
@@ Line 23: / Line 23: @@
          SimpleMatrix A = new SimpleMatrix(1,1); // will be resized
-         SimpleMatrix B = SimpleMatrix.random(3,4,-1,1,rand);
+         SimpleMatrix B = SimpleMatrix.random64(3,4,-1,1,rand);
-         SimpleMatrix C = SimpleMatrix.random(3,4,-1,1,rand);
+         SimpleMatrix C = SimpleMatrix.random64(3,4,-1,1,rand);
          eq.alias(A,"A",B,"B",C,"C");
@@ Line 60: / Line 60: @@
                          @Override
                          public void process() {
-                             DenseMatrix64F mA = ((VariableMatrix)varA).matrix;
+                             DMatrixRMaj mA = ((VariableMatrix)varA).matrix;
-                             DenseMatrix64F mB = ((VariableMatrix)varB).matrix;
+                             DMatrixRMaj mB = ((VariableMatrix)varB).matrix;
                              output.matrix.reshape(mA.numCols,mB.numCols);
-                             CommonOps.multTransA(mA,mB,output.matrix);
+                             CommonOps_DDRM.multTransA(mA,mB,output.matrix);
+                         }
                      };

@@ Line 1: / Line 1: @@
 While Equations provides many of the most common functions used in Linear Algebra, there are many it does not provide.  The following example demonstrates how to add your own functions to Equations allowing you to extend its capabilities.
-Code on GitHub:
+External Resources:
-* [https://github.com/lessthanoptimal/ejml/blob/v0.27/examples/src/org/ejml/example/EquationCustomFunction.java EquationCustomFunction]
+* [https://github.com/lessthanoptimal/ejml/blob/v0.27/examples/src/org/ejml/example/EquationCustomFunction.java EquationCustomFunction.java source code]
 == Example ==