Mdthbs

Why is a mixture of two normally distributed variables only bimodal if their means differ by at least two times the common standard deviation?

How do I explain that I don't want to maintain old projects?

Can a landlord force all residents to use the landlord's in-house debit card accounts?

Tesco's Burger Relish Best Before End date number

Converting {"type":"MultiLineString","coordinates":[[[x1,y1],[x2,y2]]]} to geography column using PostGIS?

What factors could lead to bishops establishing monastic armies?

Computer name naming convention for security

Why do airports remove/realign runways?

Blocks from @ jafe

When do flights get cancelled due to fog?

Why do people prefer metropolitan areas, considering monsters and villains?

How to "add vert" in blender 2.8?

Is it okay to use open source code to do an interview task?

How do ballistic trajectories work in a ring world?

Category-theoretic treatment of diffs, patches and merging?

How to convert diagonal matrix to rectangular matrix

What is the average number of draws it takes before you can not draw any more cards from the Deck of Many Things?

Write a function

US citizen traveling with Peruvian passport

Is there an In-Universe reason why Thor and the Asgardians think Rocket is a rabbit?

Gaining Proficiency in Vehicles (water)

How to understand flavors and when to use combination of them?

Draw a diagram with rectangles

Deck of Cards with Shuffle and Sort functionality

How to convert diagonal matrix to rectangular matrix

Is there a built in function to obtain the back diagonal of a matrix?How to select all elements above the main diagonal of matrix?Diagonal times dense matrix, high precisionHow to extract the list of all matrices from a Block Diagonal Matrix?Get rid of infinity in matrix elements (by separate definition of diagonal and off-diagonal elements)Summation over diagonal blocksHow to transform symmetric matrix to diagonal?Sum of elements in a diagonalReplace diagonal elements in sparse matrixConstructing a block diagonal matrix

.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty{ margin-bottom:0;
}

5

$begingroup$

Suppose you have the following diagonal matrix:

DiagonalMatrix[Hold/@{a, {b, c}}]//ReleaseHold

{{a, 0}, {0, {b, c}}}

How can the above matrix be converted to the following rectangular one?

{{a, 0, 0}, {0, b, c}}

list-manipulation matrix

share|improve this question

edited 8 hours ago

aleksander_si

asked 8 hours ago

aleksander_sialeksander_si

2844 bronze badges

New contributor

aleksander_si is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  Could you clarify what should happen for e.g. the matrix {{{a, d, e}, 0}, {0, {b, c}}} as in my answer? Whether my answer is correct or not hinges on this, because it gives a different answer than kglr.
  $endgroup$
  – C. E.
  11 mins ago
  
  
  

  
  
  
  

add a comment | 

5

$begingroup$

Suppose you have the following diagonal matrix:

DiagonalMatrix[Hold/@{a, {b, c}}]//ReleaseHold

{{a, 0}, {0, {b, c}}}

How can the above matrix be converted to the following rectangular one?

{{a, 0, 0}, {0, b, c}}

list-manipulation matrix

share|improve this question

edited 8 hours ago

aleksander_si

asked 8 hours ago

aleksander_sialeksander_si

2844 bronze badges

New contributor

aleksander_si is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  Could you clarify what should happen for e.g. the matrix {{{a, d, e}, 0}, {0, {b, c}}} as in my answer? Whether my answer is correct or not hinges on this, because it gives a different answer than kglr.
  $endgroup$
  – C. E.
  11 mins ago
  
  
  

  
  
  
  

add a comment | 

$begingroup$

Suppose you have the following diagonal matrix:

DiagonalMatrix[Hold/@{a, {b, c}}]//ReleaseHold

{{a, 0}, {0, {b, c}}}

How can the above matrix be converted to the following rectangular one?

{{a, 0, 0}, {0, b, c}}

list-manipulation matrix

share|improve this question

edited 8 hours ago

aleksander_si

asked 8 hours ago

aleksander_sialeksander_si

2844 bronze badges

New contributor

aleksander_si is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

$endgroup$

DiagonalMatrix[Hold/@{a, {b, c}}]//ReleaseHold

{{a, 0, 0}, {0, b, c}}

share|improve this question

edited 8 hours ago

aleksander_si

asked 8 hours ago

aleksander_sialeksander_si

2844 bronze badges

New contributor

aleksander_si is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

share|improve this question

edited 8 hours ago

aleksander_si

asked 8 hours ago

aleksander_sialeksander_si

2844 bronze badges

New contributor

aleksander_si is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

asked 8 hours ago

aleksander_sialeksander_si

2844 bronze badges

New contributor

aleksander_si is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

asked 8 hours ago

aleksander_sialeksander_si

2844 bronze badges

2 Answers
2

active

oldest

votes

1

$begingroup$

kglr's solution fails if the number of elements on the diagonal in any of the preceding rows is larger than the number of elements on the diagonal of the last row.

For example:

PadRight[Flatten /@ {{{a, d, e}, 0}, {0, {b, c}}}] // MatrixForm

m = {{a, 0, 0}, {0, {b, c, d, e, f}, 0}, {0, 0, {b, c}}}

PadRight[Flatten /@ m] // MatrixForm

Here is a different solution:

diag = Flatten[{#}] & /@ Diagonal[m];

ncols = Length@Flatten[diag];

offsets = Most@Prepend[Accumulate[Length /@ diag], 0];

row[values_, offset_, ncols_] := PadRight[ArrayPad[values, {offset, 0}], ncols]

matrix[diag_, offsets_, ncols_] := MapThread[row[#, #2, ncols] &, {diag, offsets}]



m = {{a, 0, 0}, {0, {b, c, d, e, f}, 0}, {0, 0, {b, c}}}

matrix[diag, offsets, ncols] // MatrixForm

share|improve this answer

edited 9 mins ago

answered 18 mins ago

C. E.C. E.

52.9k33 gold badges102102 silver badges210210 bronze badges

$endgroup$

add a comment | 

6

$begingroup$

PadRight[Flatten /@ {{a, 0}, {0, {b, c}}}]

{{a, 0, 0}, {0, b, c}}

share|improve this answer

answered 7 hours ago

kglrkglr

203k1010 gold badges232232 silver badges463463 bronze badges

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  Yes, in a situation where the diagonal matrix is as per the below example, then this approach should not be applied: {{a,b},0},{0,c}}
  $endgroup$
  – aleksander_si
  8 mins ago
  
  
  

  
  
  
  

add a comment | 

Your Answer

StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "387"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});


}
});

aleksander_si is a new contributor. Be nice, and check out our Code of Conduct.

draft saved

draft discarded

Sign up or log in

StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});

Sign up using Google

Sign up using Facebook

Sign up using Email and Password

Post as a guest

Name

Email

Required, but never shown

StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmathematica.stackexchange.com%2fquestions%2f201672%2fhow-to-convert-diagonal-matrix-to-rectangular-matrix%23new-answer', 'question_page');
}
);

Post as a guest

Name

Email

Required, but never shown

1

$begingroup$

kglr's solution fails if the number of elements on the diagonal in any of the preceding rows is larger than the number of elements on the diagonal of the last row.

For example:

PadRight[Flatten /@ {{{a, d, e}, 0}, {0, {b, c}}}] // MatrixForm

m = {{a, 0, 0}, {0, {b, c, d, e, f}, 0}, {0, 0, {b, c}}}

PadRight[Flatten /@ m] // MatrixForm

Here is a different solution:

diag = Flatten[{#}] & /@ Diagonal[m];

ncols = Length@Flatten[diag];

offsets = Most@Prepend[Accumulate[Length /@ diag], 0];

row[values_, offset_, ncols_] := PadRight[ArrayPad[values, {offset, 0}], ncols]

matrix[diag_, offsets_, ncols_] := MapThread[row[#, #2, ncols] &, {diag, offsets}]



m = {{a, 0, 0}, {0, {b, c, d, e, f}, 0}, {0, 0, {b, c}}}

matrix[diag, offsets, ncols] // MatrixForm

share|improve this answer

edited 9 mins ago

answered 18 mins ago

C. E.C. E.

52.9k33 gold badges102102 silver badges210210 bronze badges

$endgroup$

add a comment | 

1

$begingroup$

kglr's solution fails if the number of elements on the diagonal in any of the preceding rows is larger than the number of elements on the diagonal of the last row.

For example:

PadRight[Flatten /@ {{{a, d, e}, 0}, {0, {b, c}}}] // MatrixForm

m = {{a, 0, 0}, {0, {b, c, d, e, f}, 0}, {0, 0, {b, c}}}

PadRight[Flatten /@ m] // MatrixForm

Here is a different solution:

diag = Flatten[{#}] & /@ Diagonal[m];

ncols = Length@Flatten[diag];

offsets = Most@Prepend[Accumulate[Length /@ diag], 0];

row[values_, offset_, ncols_] := PadRight[ArrayPad[values, {offset, 0}], ncols]

matrix[diag_, offsets_, ncols_] := MapThread[row[#, #2, ncols] &, {diag, offsets}]



m = {{a, 0, 0}, {0, {b, c, d, e, f}, 0}, {0, 0, {b, c}}}

matrix[diag, offsets, ncols] // MatrixForm

share|improve this answer

edited 9 mins ago

answered 18 mins ago

C. E.C. E.

52.9k33 gold badges102102 silver badges210210 bronze badges

$endgroup$

add a comment | 

$begingroup$

kglr's solution fails if the number of elements on the diagonal in any of the preceding rows is larger than the number of elements on the diagonal of the last row.

For example:

PadRight[Flatten /@ {{{a, d, e}, 0}, {0, {b, c}}}] // MatrixForm

m = {{a, 0, 0}, {0, {b, c, d, e, f}, 0}, {0, 0, {b, c}}}

PadRight[Flatten /@ m] // MatrixForm

Here is a different solution:

diag = Flatten[{#}] & /@ Diagonal[m];

ncols = Length@Flatten[diag];

offsets = Most@Prepend[Accumulate[Length /@ diag], 0];

row[values_, offset_, ncols_] := PadRight[ArrayPad[values, {offset, 0}], ncols]

matrix[diag_, offsets_, ncols_] := MapThread[row[#, #2, ncols] &, {diag, offsets}]



m = {{a, 0, 0}, {0, {b, c, d, e, f}, 0}, {0, 0, {b, c}}}

matrix[diag, offsets, ncols] // MatrixForm

share|improve this answer

edited 9 mins ago

answered 18 mins ago

C. E.C. E.

52.9k33 gold badges102102 silver badges210210 bronze badges

$endgroup$

PadRight[Flatten /@ {{{a, d, e}, 0}, {0, {b, c}}}] // MatrixForm

m = {{a, 0, 0}, {0, {b, c, d, e, f}, 0}, {0, 0, {b, c}}}

PadRight[Flatten /@ m] // MatrixForm

diag = Flatten[{#}] & /@ Diagonal[m];

ncols = Length@Flatten[diag];

offsets = Most@Prepend[Accumulate[Length /@ diag], 0];

row[values_, offset_, ncols_] := PadRight[ArrayPad[values, {offset, 0}], ncols]

matrix[diag_, offsets_, ncols_] := MapThread[row[#, #2, ncols] &, {diag, offsets}]



m = {{a, 0, 0}, {0, {b, c, d, e, f}, 0}, {0, 0, {b, c}}}

matrix[diag, offsets, ncols] // MatrixForm

share|improve this answer

edited 9 mins ago

answered 18 mins ago

C. E.C. E.

52.9k33 gold badges102102 silver badges210210 bronze badges

answered 18 mins ago

C. E.C. E.

52.9k33 gold badges102102 silver badges210210 bronze badges

answered 18 mins ago

C. E.C. E.

52.9k33 gold badges102102 silver badges210210 bronze badges

6

$begingroup$

PadRight[Flatten /@ {{a, 0}, {0, {b, c}}}]

{{a, 0, 0}, {0, b, c}}

share|improve this answer

answered 7 hours ago

kglrkglr

203k1010 gold badges232232 silver badges463463 bronze badges

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  Yes, in a situation where the diagonal matrix is as per the below example, then this approach should not be applied: {{a,b},0},{0,c}}
  $endgroup$
  – aleksander_si
  8 mins ago
  
  
  

  
  
  
  

add a comment | 

6

$begingroup$

PadRight[Flatten /@ {{a, 0}, {0, {b, c}}}]

{{a, 0, 0}, {0, b, c}}

share|improve this answer

answered 7 hours ago

kglrkglr

203k1010 gold badges232232 silver badges463463 bronze badges

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  Yes, in a situation where the diagonal matrix is as per the below example, then this approach should not be applied: {{a,b},0},{0,c}}
  $endgroup$
  – aleksander_si
  8 mins ago
  
  
  

  
  
  
  

add a comment | 

$begingroup$

PadRight[Flatten /@ {{a, 0}, {0, {b, c}}}]

{{a, 0, 0}, {0, b, c}}

share|improve this answer

answered 7 hours ago

kglrkglr

203k1010 gold badges232232 silver badges463463 bronze badges

$endgroup$

PadRight[Flatten /@ {{a, 0}, {0, {b, c}}}]

share|improve this answer

answered 7 hours ago

kglrkglr

203k1010 gold badges232232 silver badges463463 bronze badges

answered 7 hours ago

kglrkglr

203k1010 gold badges232232 silver badges463463 bronze badges

answered 7 hours ago

kglrkglr

203k1010 gold badges232232 silver badges463463 bronze badges