WOLFRAM SYSTEMMODELER

AutomaticSeed

Demonstrates noise with startTime and automatic local seed for UniformNoise

Diagram

Wolfram Language

In[1]:=
SystemModel["Modelica.Blocks.Examples.NoiseExamples.AutomaticSeed"]
Out[1]:=

Information

This information is part of the Modelica Standard Library maintained by the Modelica Association.

This example demonstrates manual and automatic seed selection of UniformNoise blocks, as well as starting the noise at startTime = 0.5 s with an output value of y = -1 before this time. All noise blocks in this example generate uniform noise in the band y_min=-1 .. y_max=3 with samplePeriod = 0.01 s.

The blocks automaticSeed1, automaticSeed2, automaticSeed3 use the default option to automatically initialize the pseudo random number generators of the respective block. As a result, different noise is generated, see next diagram:

The blocks manualSeed1, manualSeed2, manualSeed3 use manual selection of the local seed (useAutomaticLocalSeed = false). They use a fixedLocalSeed of 1, 2, and 3 respectively. Again, different noise is generated, see next diagram:

Try to set fixedLocalSeed = 1 in block manualSeed2. As a result, the blocks manualSeed1 and manualSeed2 will produce exactly the same noise.

Parameters (2)

startTime

Value: 0.5

Type: Time (s)

Description: Start time of noise

y_off

Value: -1.0

Type: Real

Description: Output of block before startTime

Outputs (3)

manualSeed1_y

Default Value: manualSeed1.y

Type: Real

manualSeed2_y

Default Value: manualSeed2.y

Type: Real

manualSeed3_y

Default Value: manualSeed3.y

Type: Real

Components (7)

globalSeed

Type: GlobalSeed

automaticSeed1

Type: UniformNoise

automaticSeed2

Type: UniformNoise

automaticSeed3

Type: UniformNoise

manualSeed1

Type: UniformNoise

manualSeed2

Type: UniformNoise

manualSeed3

Type: UniformNoise