Avoid discontinuities

[HansOlsson]

Closes #3548
The idea is that it often makes sense to have continuous input signals, and Sine, Cosine, and Sinc-blocks didn't guarantee that.

That is now possible on a flag.

[henrikt-ma]

Seems OK now.

I suppose it is intentional to not force continuous to be evaluated?

[Harisankar-Allimangalath]

By making it continuous we mean it should be differentiable right, but even with the new flag addition and smooth function

• sine block would only be continuous at a phase of 90 an 270, with any offset and start time not 0.

• same is the case with cosine also it only works well if the phase is 0 or 180 with any offset and start time not 0

because for both cases at start time (if its not 0) there will be discontinuity, I did the cross checking in Dymola with a Der block (Modelica.Blocks.Continuous.Der) and it failed can you please cross verify the same @henrikt-ma @HansOlsson @beutlich

• The sinc modification was working fine.

[HansOlsson]

By making it continuous we mean it should be differentiable right

Unfortunately not for sine and cosine. (Well, at least not with a continuous derivative.)

The way to make the derivative continuous would be to modify the behavior before startTime to not be a constant signal, and I find that too disruptive.

model Unnamed
  Modelica.Blocks.Sources.Sine sine(
    f=0.1,
    phase=4.2411500823462,
    continuous=true,
    startTime=0.9)
    annotation (Placement(transformation(extent={{-68,-36},{-48,-16}})));
  Modelica.Blocks.Continuous.Der der1
    annotation (Placement(transformation(extent={{-16,-36},{4,-16}})));
  Modelica.Blocks.Sources.Sine sine1(
    f=0.1,
    phase=4.2411500823462,
    continuous=false,
    startTime=0.9)
    annotation (Placement(transformation(extent={{-64,30},{-44,50}})));
equation 
  connect(sine.y, der1.u)
    annotation (Line(points={{-47,-26},{-18,-26}}, color={0,0,127}));
  annotation (uses(Modelica(version="4.0.0")));
end Unnamed;

[Harisankar-Allimangalath]

@MartinOtter and @AHaumer can you please give your suggestion on how to proceed with this ticket .Thankyou