Difference between revisions of "Slices"

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This assignment has been replaced by [[Ranges]].
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<!--
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credit for this assignment: Finn Voichick and Dennis Cosgrove
 
credit for this assignment: Finn Voichick and Dennis Cosgrove
  
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This studio is about creating an easier way to split data so that it can be worked on in parallel. The splitting of the data is still done sequentially. That means at no point in this studio should you be using async() or finish().
 
This studio is about creating an easier way to split data so that it can be worked on in parallel. The splitting of the data is still done sequentially. That means at no point in this studio should you be using async() or finish().
  
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{{warning | Do NOT Copy The Data Into SubArrays}}
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=Code To Investigate=
 +
[https://www.cse.wustl.edu/~cosgroved/courses/cse231/current/apidocs/slice/core/IndexedRange.html class IndexedRange]
 +
:[https://www.cse.wustl.edu/~cosgroved/courses/cse231/current/apidocs/slice/core/IndexedRange.html#%3Cinit%3E(int,int,int) constructor].
  
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Our "Slices" will actually be a list of objects called "Slice". A Slice contains a couple things, one of them being the full, original data that is passed through at the start. It is important that the entire array is given to the Slice. Not a copy of the array, nor a shortened version of the array, but the ''entire'' thing.
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<pre>public IndexedRange(int sliceIndexId, int minInclusive, int maxExclusive)</pre>
  
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=class Slice<T>=
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This class has everything you need for [[Nucleobase_Counting#Coarsening_N-Way_Split|n-way split]] problems, specifically: [https://www.cse.wustl.edu/~cosgroved/courses/cse231/current/apidocs/slice/core/IndexedRange.html#getSliceIndexId() getSliceIndexId()], [https://www.cse.wustl.edu/~cosgroved/courses/cse231/current/apidocs/slice/core/IndexedRange.html#getMinInclusive() getMinInclusive()], and [https://www.cse.wustl.edu/~cosgroved/courses/cse231/current/apidocs/slice/core/IndexedRange.html#getMaxExclusive() getMaxExclusive()].
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use: [https://www.cse.wustl.edu/~cosgroved/courses/cse231/current/apidocs/slice/core/Slice.html class Slice]
 
  
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This class has everything you need for [[Nucleobase_Counting#Coarsening_N-Way_Split|n-way split]] problems, specifically: [https://www.cse.wustl.edu/~cosgroved/courses/cse231/current/apidocs/slice/core/Slice.html#getSliceIndexId-- getSliceIndexId()], [https://www.cse.wustl.edu/~cosgroved/courses/cse231/current/apidocs/slice/core/Slice.html#getMinInclusive-- getMinInclusive()], and [https://www.cse.wustl.edu/~cosgroved/courses/cse231/current/apidocs/slice/core/Slice.html#getMaxExclusive-- getMaxExclusive()].
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=Code to Implement=
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{{CodeToImplement|Slices|createNSlices|slices.studio}}
  
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[https://www.cse.wustl.edu/~cosgroved/courses/cse231/current/apidocs/slice/core/Slice.html#getOriginalUnslicedData-- getOriginalUnslicedData()] is not necessary until the [[K-MerCounting_Assignment|K-Mer Counting Lab]]
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==createNSlices==
  
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{{Sequential|public static List<IndexedRange> createNSlices(int minInclusive, int maxExclusive, int numSlices)}}
  
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=Code to Implement=
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Given a range [minInclusive, maxExclusive) and a number of slices to make, return a List of IndexedRanges. Understanding what a IndexedRange is and how it is used is important when writing this solution.  
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{{CodeToImplement|Slices|createNSlicesForArrayObject|slices.studio}}
 
  
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==createNSlicesForArrayObject==
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The goal is to have each slice's range be the entire array when put together, with no overlap. Some examples are giving below. Working through more examples can be a helpful way of figuring out what code to write if you get stuck.
  
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{{Sequential|private static <A> List<Slice<A>> createNSlicesForArrayObject(A data, int numSlices)}}
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{{ tip | In a slice, the minimum is inclusive and the maximum is exclusive.  This means for two slices next to each other, slice1.getMaxExclusive() is equal to slice2.getMinInclusive(). }}
  
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Given an Array (A) and a number of slices to make, return a List of object Slice. Make sure to read through the Javadocs for the Slice class (linked above) before writing any code. Understanding what a Slice is and how it is used is important when writing this solution.  
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==Strict Specification==
 +
We are overly strict about the specification of how the data '''must''' be sliced up.  This is to allow to accurately compare results intermediate results throughout the semester.
  
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Note that a Slice has a minimum and maximum value. This acts as the "range" that sections off a part of the original array. The goal is to have each slice's range be the entire array when put together, with no overlap. Some examples are giving below. Working through more examples can be a helpful way of figuring out what code to write if you get stuck.
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'''Example: array.length=8; numSlices=4'''
  
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{{ tip | Because we are working with something of type A, "data.length" is not possible. To get the size of "data", we will need to use the [https://docs.oracle.com/javase/8/docs/api/java/lang/reflect/Array.html#getLength-java.lang.Object- Array.getLength(Object)] method. }}
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{| class="wikitable"
 +
|A
 +
|A
 +
|B
 +
|B
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|C
 +
|C
 +
|D
 +
|D
 +
|}
  
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{{ tip | In a slice, the minimum is inclusive and the maximum is exclusive.  This means for two slices next to each other, slice1.getMaxExclusive() is equal to slice2.getMinInclusive(). }}
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{| class="wikitable"
 +
|-
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!Slice ID !! Min Inclusive !! Max Exclusive
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|-
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|0 || 0 || 2
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|-
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|1 || 2 || 4
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|-
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|2 || 4 || 6
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|-
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|3 || 6 || 8
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|}
  
  
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In order to support primitive arrays (e.g. byte[], int[], et cetera) and non-primitive arrays (e.g. Object[]) we provide all of the public methods, each which simply call the single method requiring implementation:
 
  
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<nowiki> public static <T> List<Slice<T[]>> createNSlices(T[] data, int numSlices) {
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'''Example: array.length=7; numSlices=4'''
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return createNSlicesForArrayObject(data, numSlices);
 
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}
 
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public static List<Slice<byte[]>> createNSlices(byte[] data, int numSlices) {
 
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return createNSlicesForArrayObject(data, numSlices);
 
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}
 
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public static List<Slice<char[]>> createNSlices(char[] data, int numSlices) {
 
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return createNSlicesForArrayObject(data, numSlices);
 
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}
 
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public static List<Slice<short[]>> createNSlices(short[] data, int numSlices) {
 
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return createNSlicesForArrayObject(data, numSlices);
 
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}
 
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public static List<Slice<int[]>> createNSlices(int[] data, int numSlices) {
 
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return createNSlicesForArrayObject(data, numSlices);
 
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}
 
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public static List<Slice<long[]>> createNSlices(long[] data, int numSlices) {
 
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return createNSlicesForArrayObject(data, numSlices);
 
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}
 
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public static List<Slice<float[]>> createNSlices(float[] data, int numSlices) {
 
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return createNSlicesForArrayObject(data, numSlices);
 
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}
 
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public static List<Slice<double[]>> createNSlices(double[] data, int numSlices) {
 
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return createNSlicesForArrayObject(data, numSlices);
 
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}</nowiki>
 
  
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=Strict Specification=
 
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We are overly strict about the specification of how the data '''must''' be sliced up.  This is to allow to accurately compare results intermediate results throughout the semester.
 
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==Example: array.length=7; numSlices=4==
 
 
Distribute the remainder 1 each to the lower end slices (the first few slices or the lower index slices).
 
Distribute the remainder 1 each to the lower end slices (the first few slices or the lower index slices).
  
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|C
 
|C
 
|D
 
|D
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|}
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{| class="wikitable"
 +
|-
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!Slice ID !! Min Inclusive !! Max Exclusive
 +
|-
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|0 || 0 || 2
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|-
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|1 || 2 || 4
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|-
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|2 || 4 || 6
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|-
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|3 || 6 || 7
 
|}
 
|}
  
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|D
 
|D
 
</s>
 
</s>
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Giving all the remainder to one slice defeats the purpose of balancing the workload!
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==Convenience Methods==
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 +
In order to support primitive arrays (e.g. byte[], int[], et cetera) and non-primitive arrays (e.g. Object[]) we provide all of the public methods, each which simply call the single method requiring implementation:
 +
 +
<nowiki> public static <C> List<IndexedRange> createNSlices(C[] data, int numSlices) {
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return createNSlices(0, data.length, numSlices);
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}
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public static List<IndexedRange> createNSlices(byte[] data, int numSlices) {
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return createNSlices(0, data.length, numSlices);
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}
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public static List<IndexedRange> createNSlices(char[] data, int numSlices) {
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return createNSlices(0, data.length, numSlices);
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}
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public static List<IndexedRange> createNSlices(short[] data, int numSlices) {
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return createNSlices(0, data.length, numSlices);
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}
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public static List<IndexedRange> createNSlices(int[] data, int numSlices) {
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return createNSlices(0, data.length, numSlices);
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}
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public static List<IndexedRange> createNSlices(long[] data, int numSlices) {
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return createNSlices(0, data.length, numSlices);
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}
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public static List<IndexedRange> createNSlices(float[] data, int numSlices) {
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return createNSlices(0, data.length, numSlices);
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}
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public static List<IndexedRange> createNSlices(double[] data, int numSlices) {
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return createNSlices(0, data.length, numSlices);
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}</nowiki>
  
 
=Testing Your Solution=
 
=Testing Your Solution=
 
==Correctness==
 
==Correctness==
 
{{TestSuite|SlicesTestSuite|slice.studio}}
 
{{TestSuite|SlicesTestSuite|slice.studio}}
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=Pledge, Acknowledgments, Citations=
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{{Pledge|studio-slices}}
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-->

Latest revision as of 21:56, 30 November 2022

This assignment has been replaced by Ranges.

Retrieved from "http://classes.engineering.wustl.edu/cse231/core/index.php?title=Slices&oldid=4155"