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EET 2259 Unit 10 Clusters 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. - PowerPoint PPT Presentation
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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.
Floyd, Digital Fundamentals, 10th ed
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)
Floyd, Digital Fundamentals, 10th ed
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.
Floyd, Digital Fundamentals, 10th ed
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)
Floyd, Digital Fundamentals, 10th ed
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)
Floyd, Digital Fundamentals, 10th ed
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)
Floyd, Digital Fundamentals, 10th ed
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.
Floyd, Digital Fundamentals, 10th ed
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)
Floyd, Digital Fundamentals, 10th ed
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)
Floyd, Digital Fundamentals, 10th ed
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)
Floyd, Digital Fundamentals, 10th ed
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.
Floyd, Digital Fundamentals, 10th ed
Bundle
One use of the Bundle function is to assemble objects into a new cluster.
Floyd, Digital Fundamentals, 10th ed
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.
Floyd, Digital Fundamentals, 10th ed
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)
Floyd, Digital Fundamentals, 10th ed
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.
Floyd, Digital Fundamentals, 10th ed
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.
Floyd, Digital Fundamentals, 10th ed
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.
Floyd, Digital Fundamentals, 10th ed
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
Floyd, Digital Fundamentals, 10th ed
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.
Floyd, Digital Fundamentals, 10th ed
Step 1. Applying KVL
In our circuit, applyingKVL to the three loops gives us the following system of equations:
Floyd, Digital Fundamentals, 10th ed
Step 2. Solving the System of Equations in LabVIEW
Floyd, Digital Fundamentals, 10th ed
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.