Floyd, Digital Fundamentals, 10 th ed EET 2259 Unit 10 Clusters and Matrices Read Bishop, Sections...

Floyd, Digital Fundamentals, 10th ed

EET 2259 Unit 10Clusters and Matrices

Read Bishop, Sections 6.4 to 6.10.

Lab #10 and Homework #10 due next week.

Exam #2 next week.


Polymorphism

Polymorphism is a feature of functions in modern programming languages such as LabVIEW.

It lets a single function work on inputs of different dimensions and data types.

This allows one function to do the work that you’d need several different functions to do in older languages that don’t have polymorphism.

(Bishop, p. 310)


Polymorphism Example: Add

LabVIEW’s Add function is an example of a polymorphic function.

It can add a scalar plus a scalar, or a scalar plus an array, or an array plus an array.

In non-polymorphic languages, this would require several different functions.


Clusters

Recall that an array is a variable-sized collection of elements that are all of the same data type (such as numeric, string, or Boolean).

In contrast, a cluster is a fixed-sized collection of elements of mixed data types.

(Bishop, p. 313)


Usefulness of Clusters

Clusters are useful when you have a related group of elements of different data types that you want to associate with each other. Example: you might group a string containing a

person’s name together with an integer containing his/her age and a Boolean indicating his/her citizenship status.

Clusters often let you simplify block diagrams by reducing the number of wires on the diagram.

(Bishop, p. 314)


Creating a Cluster of Controls or Indicators

To create a cluster of controls or indicators:

1. Place a cluster shell on the front panel from the Controls >> Modern >> Array, Matrix & Cluster palette.

2. Place controls or indicators inside that cluster shell.

(Bishop, pp. 314-315)


Brown or Pink?

On the block diagram, cluster terminals and cluster wires are colored brown if all of the items in the cluster are numeric.

But the terminals and wires are colored pink if one or more of the items are non-numeric.


Order within a Cluster

Individual items within a cluster are referred to by the order in which they were placed in the cluster.

The first item placed in a cluster becomes element 0, the next item placed in the cluster becomes element 1, and so on.

To change the order, right-click a cluster’s border on the front panel and select Reorder Controls in Cluster.

(Bishop, p. 316)


Connecting Control Cluster to Indicator Cluster

You can wire a control cluster to an indicator cluster if they contain the same number of elements and if the data types of the corresponding elements match. Example: if a control cluster’s element 0 is a

string control and its element 1 is a numeric control, you could not wire it to an indicator cluster whose element 0 is a numeric indicator and whose element 1 is a string indicator.

(Bishop, p. 317)


Cluster Functions

LabVIEW provides several functions for working with clusters, including:

Unbundle Unbundle By Name Bundle Bundle By Name

These and others are on the Functions >> Programming >> Cluster & Variant palette.

(Bishop, p. 319)


Unbundle and Unbundle By Name

The Unbundle and Unbundle By Name functions are used to split a cluster into its individual objects.

(Bishop, p. 323)

Recommendation: Use Unbundle By Name instead of Unbundle.


Bundle

One use of the Bundle function is to assemble objects into a new cluster.


Bundle and Bundle By Name

Another use of the Bundle function is to change the value of elements in an existing cluster. The Bundle By Name function can also be used in this way.

Recommendation: Use Bundle By Name instead of Bundle.


Cluster Example: Displaying Multiple Plots on a Chart

Many LabVIEW indicators and functions have input terminals that can accept clusters.

Example: To display more than one plot on a waveform chart, bundle the data together using the Bundle function. (We’ll discuss charts in more detail next week.)

(Bishop, p. 351)


Matrices

A matrix is a two-dimensional array of numbers. (And a vector is a one-dimensional array of numbers.)

The branch of math called linear algebra studies rules and techniques for manipulating matrices and vectors.

Scientists and engineers use matrices and vectors to solve many types of problems.


Matrices in LabVIEW

LabVIEW has a matrix datatype that is basically a special case of the array datatype.

A matrix must be two-dimensional, and it can only hold numbers (real or complex).

LabVIEW does not have a special vector datatype: just use a 1-D array.


LabVIEW Matrix Functions

LabVIEW has a large collection of powerful functions that work on matrices and vectors.

See the Programming > Array > Matrix palette and the Mathematics > Linear Algebra palette.


Solving Systems of Linear Equations

As a simple example, matrices can be used to solve systems of linear equations, which arise in many applications.

Applications include the circuit-analysis techniques called mesh analysis and nodal analysis that you studied in DC Circuits (EET 1150).

Suppose we want to find the currents in the circuit on the next slide….

Principles of Electric Circuits: Conventional Current Version, 8eBy Thomas L. Floyd

© 2007 Pearson Education, Inc.Pearson Prentice Hall

Upper Saddle River, NJ 07458

Figure 9–14


Mesh Analysis

Mesh analysis (also called “loop analysis”) involves three steps:

1. Apply Kirchhoff’s Voltage Law (KVL) around each loop to set up a system of linear equations. LabVIEW can’t help with this step; you have to do it by hand.

2. Solve the system of linear equations. Doing this by hand can be tedious, but with LabVIEW it’s easy.

3. Interpret the results of Step 2.


Step 1. Applying KVL

In our circuit, applyingKVL to the three loops gives us the following system of equations:


Step 2. Solving the System of Equations in LabVIEW


Step 3. Interpreting the Results

To interpret the results we must recognize that in the original circuit,

This gives us the current through each resistor.

Floyd, Digital Fundamentals, 10 th ed EET 2259 Unit 10 Clusters and Matrices Read Bishop, Sections...

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