Relational and Logical Operators

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This example shows how to implement relational and logical operators by using Simulink® blocks, Stateflow® Charts, and MATLAB® Function blocks.

Modeling Pattern for Relational or Logical Operators — Simulink Blocks

To include a logical operation in your model, use the Logical Operator block from the Logic and Bit Operations library.

1. Open example model ex_data_type_SL.

The Logical Operator block performs an OR operation in the model. To change the operation, double-click the block and set the Operator field to any of the operations in the menu.

You can implement relational operators by replacing the Logical Operator block with a Relational Operator block.

2. To build the model and generate code, press Ctrl+B.

The code implementing the logical operator OR is in the ex_logical_SL_step function in ex_logical_SL.c.

/* Exported block signals */
boolean_T u1;                          /* '<Root>/u1' */
boolean_T u2;                          /* '<Root>/u2' */
boolean_T y1;                          /* '<Root>/y1' */

/* Model step function */
void ex_logical_SL_step(void)
{
  /* Outport: '<Root>/y1' incorporates:
   *  Inport: '<Root>/u1'
   *  Inport: '<Root>/u2'
   *  Logic: '<Root>/Logical Operator'
   */
  y1 = (u1 || u2);
}

Modeling Pattern for Relational and Logical Operators — Stateflow Chart

1. Open example model ex_data_type_SF.

In the Stateflow chart, the relational or logical operation actions are on the transition from one junction to another. Relational statements specify conditions to conditionally allow a transition. In that case, the statements are within square brackets.

2. To build the model and generate code, press Ctrl+B.

The code implementing the logical operator OR is in the ex_logical_SF_step function in ex_logical_SF.c.

/* Exported block signals */
boolean_T u1;                          /* '<Root>/u1' */
boolean_T u2;                          /* '<Root>/u2' */
boolean_T y1;                          /* '<Root>/Logical Operator' */

/* Model step function */
void ex_logical_SF_step(void)
{
  /* Chart: '<Root>/Logical Operator' incorporates:
   *  Inport: '<Root>/u1'
   *  Inport: '<Root>/u2'
   */
  y1 = (u1 || u2);
}

Modeling Pattern for Relational and Logical Operators — MATLAB Function Block

This example shows the MATLAB Function block method for incorporating operators into the generated code by using a relational operator.

1. Open example model ex_logical_ML.

2. The MATLAB Function Block contains this function:

function y1 = fcn(u1, u2)
y1 = u1 > u2; 
end

3. To build the model and generate code, press Ctrl+B.

The generated code appears in ex_data_type_ML.c:

/* Exported block signals */
real_T u1;                             /* '<Root>/u1' */
real_T u2;                             /* '<Root>/u2' */
boolean_T y;                           /* '<Root>/MATLAB Function' */

/* Model step function */
void ex_logical_ML_step(void)
{
  /* MATLAB Function: '<Root>/MATLAB Function' incorporates:
   *  Inport: '<Root>/u1'
   *  Inport: '<Root>/u2'
   */
  y = (u1 > u2);
}

See Also