Problem 1852. Repeat middle rows and columns of an array

Created by Matthew Eicholtz

Solve Later

{"relationships":[{"relationshipType":"http://schemas.mathworks.com/matlab/code/2013/relationships/document","targetMode":"","relationshipId":"rId1","target":"/matlab/document.xml"},{"relationshipType":"http://schemas.mathworks.com/matlab/code/2013/relationships/output","targetMode":"","relationshipId":"rId2","target":"/matlab/output.xml"}],"parts":[{"partUri":"/matlab/document.xml","relationship":[],"contentType":"application/vnd.mathworks.matlab.code.document+xml","content":"<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<w:document xmlns:w=\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\"><w:body><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>Given an MxN numeric array (A), return an array (B) in which the middle rows and columns have each been repeated once. It may be easier to think of this problem as two operations: (1) repeat the middle rows, and then (2) repeat the middle columns.</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>The motivation for this problem is to create an array that, when used in</w:t></w:r><w:r><w:t> </w:t></w:r><w:r><w:rPr><w:i/></w:rPr><w:t>blockproc(B,[2 2],fun)</w:t></w:r><w:r><w:t>, effectively incorporates a sliding window with 50% overlap. (NOTE: yes,</w:t></w:r><w:r><w:t> </w:t></w:r><w:r><w:rPr><w:i/></w:rPr><w:t>nlfilter</w:t></w:r><w:r><w:t> will work on array A, but it requires that the processing output be a scalar, whereas</w:t></w:r><w:r><w:t> </w:t></w:r><w:r><w:rPr><w:i/></w:rPr><w:t>blockproc</w:t></w:r><w:r><w:t> does not)</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>You may assume that M&gt;1, N&gt;1 (i.e. no scalars or vectors).</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:rPr><w:b/></w:rPr><w:t>Example</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>If</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"code\"/></w:pPr><w:r><w:t><![CDATA[A = [1  2  3  4\n     5  6  7  8\n     9  10 11 12\n     13 14 15 16]]]></w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>Then</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"code\"/></w:pPr><w:r><w:t><![CDATA[B = [1  2  2  3  3  4\n     5  6  6  7  7  8\n     5  6  6  7  7  8\n     9  10 10 11 11 12\n     9  10 10 11 11 12\n     13 14 14 15 15 16]]]></w:t></w:r></w:p></w:body></w:document>"},{"partUri":"/matlab/output.xml","contentType":"text/xml","content":"<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\" ?><embeddedOutputs><metaData><evaluationState>manual</evaluationState><layoutState>code</layoutState><outputStatus>ready</outputStatus></metaData><outputArray type=\"array\"/><regionArray type=\"array\"/></embeddedOutputs>"}]}

Solve

Solution Stats

81 Solutions
31 Solvers

Last Solution submitted on Jun 02, 2021

Last 200 Solutions

Problem Comments

Solution Comments

Solution 312706

2 Comments

2 Comments

Swapnali Gujar on 3 Sep 2013

lovely !

Jan Orwat on 10 Sep 2013

doesn't it work only for square matrices? :P

Problem Recent Solvers31

Problem Tags

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Problem 1852. Repeat middle rows and columns of an array

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers31

Suggested Problems

More from this Author44

Problem Tags

Community Treasure Hunt

Problem 1852. Repeat middle rows and columns of an array

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers31

Suggested Problems

More from this Author44

Problem Tags

Community Treasure Hunt

Players