WOLFRAM SYSTEM MODELER
regStepApproximation of a general step, such that the characteristic is continuous and differentiable |
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Wolfram Language
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SystemModel["Modelica.Fluid.Utilities.regStep"]
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Information
This information is part of the Modelica Standard Library maintained by the Modelica Association.
This function is used to approximate the equation
y = if x > 0 then y1 else y2;
by a smooth characteristic, so that the expression is continuous and differentiable:
y = smooth(1, if x > x_small then y1 else
if x < -x_small then y2 else f(y1, y2));
In the region -x_small < x < x_small a 2nd order polynomial is used for a smooth transition from y1 to y2.
Syntax
y = regStep(x, y1, y2, x_small)
Inputs (4)
| x |
Type: Real Description: Abscissa value |
|---|---|
| y1 |
Type: Real Description: Ordinate value for x > 0 |
| y2 |
Type: Real Description: Ordinate value for x < 0 |
| x_small |
Default Value: 1e-5 Type: Real Description: Approximation of step for -x_small <= x <= x_small; x_small >= 0 required |
Outputs (1)
| y |
Type: Real Description: Ordinate value to approximate y = if x > 0 then y1 else y2 |
|---|
Revisions
- April 29, 2008
by Martin Otter:
Designed and implemented. - August 12, 2008
by Michael Sielemann:
Minor modification to cover the limit casex_small -> 0without division by zero.