Problem 647. Getting the absolute index from a matrix

Created by Doug Hull

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>This is a basic MATLAB operation. It is for instructional purposes.</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>---</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>You may already know how to get the</w:t></w:r><w:r><w:t> </w:t></w:r><w:hyperlink w:docLocation=\"http://www.mathworks.com/matlabcentral/cody/problems/646-getting-the-row-and-column-location-from-a-matrix\"><w:r><w:t>row and column index from a matrix</w:t></w:r></w:hyperlink><w:r><w:t>, and the</w:t></w:r><w:r><w:t> </w:t></w:r><w:hyperlink w:docLocation=\"http://www.mathworks.com/matlabcentral/cody/problems/640-do-a-binary-comparison-on-a-vector\"><w:r><w:t>logical indexing</w:t></w:r></w:hyperlink><w:r><w:t> technique but there is another way to reference specific elements in a matrix.</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>Absolute indexing refers to specific elements with a single scalar rather than two (row and column). The upper left entry is value 1, the lower right is the highest value. MATLAB is column major, so you count down the rows in a specific column first, moving right as needed until you reach the end.</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:hyperlink w:docLocation=\"http://www.mathworks.com/matlabcentral/cody/problems/645-getting-the-indices-from-a-vector\"><w:r><w:t>Indexing into a vector</w:t></w:r></w:hyperlink><w:r><w:t> is really using this kind of indexing, but it is more natural feeling.</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>Use</w:t></w:r><w:r><w:t> </w:t></w:r><w:hyperlink w:docLocation=\"http://www.mathworks.com/help/techdoc/ref/find.html\"><w:r><w:t>Find</w:t></w:r></w:hyperlink><w:r><w:t>.</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>Given a matrix M, return the absolute indices where M is greater than scalar, LB (Lower Bound) and less than UB (Upper Bound). (See</w:t></w:r><w:r><w:t> </w:t></w:r><w:hyperlink w:docLocation=\"http://www.mathworks.com/matlabcentral/cody/problems/640-do-a-binary-comparison-on-a-vector\"><w:r><w:t>Binary comparison</w:t></w:r></w:hyperlink><w:r><w:t> to satisfy two conditions)</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>"}]}

This is a basic MATLAB operation. It is for instructional purposes.---You may already know how to get the <a href="http://www.mathworks.com/matlabcentral/cody/problems/646-getting-the-row-and-column-location-from-a-matrix">row and column index from a matrix</a>, and the <a href="http://www.mathworks.com/matlabcentral/cody/problems/640-do-a-binary-comparison-on-a-vector">logical indexing</a> technique but there is another way to reference specific elements in a matrix.Absolute indexing refers to specific elements with a single scalar rather than two (row and column). The upper left entry is value 1, the lower right is the highest value. MATLAB is column major, so you count down the rows in a specific column first, moving right as needed until you reach the end.<a href="http://www.mathworks.com/matlabcentral/cody/problems/645-getting-the-indices-from-a-vector">Indexing into a vector</a> is really using this kind of indexing, but it is more natural feeling.Use <a href="http://www.mathworks.com/help/techdoc/ref/find.html">Find</a>.Given a matrix M, return the absolute indices where M is greater than scalar, LB (Lower Bound) and less than UB (Upper Bound). (See <a href="http://www.mathworks.com/matlabcentral/cody/problems/640-do-a-binary-comparison-on-a-vector">Binary comparison</a> to satisfy two conditions)

Solve

Solution Stats

276 Solutions
202 Solvers

Last Solution submitted on Aug 10, 2020

Last 200 Solutions

Problem Comments

1 Comment

1 Comment

Informaton on 29 May 2017

The test suite gives an answer.

Problem Recent Solvers202

Problem Tags

indexing ml101

Problem 647. Getting the absolute index from a matrix

Solution Stats

Last 200 Solutions

Problem Comments

Problem Recent Solvers202

Suggested Problems

More from this Author52

Problem Tags

Problem 647. Getting the absolute index from a matrix

Solution Stats

Last 200 Solutions

Problem Comments

Problem Recent Solvers202

Suggested Problems

More from this Author52

Problem Tags

Players