What code can be used to create a diagonal matrix in javascript

Question

I have the following matrix in javascript, modelled with the library math.js:

<script src='math.js' src='sylvester.js' type='text/javascript'></script>

var CN = math.matrix([[8], [7],[3],[1]])

I would like to change this matrix into a diagonal matrix:
<script src='math.js' src='sylvester.js' type='text/javascript'></script>

var CN = math.matrix([[8,0,0,0], [0,7,0,0],[0,0,3,0], [0,0,0,1]]);

I cannot find the appropriate code for this to do so.
Can someone help me with the appropriate code?

Programming is not about "finding" code but about writing it. And this community is for developers, not copy-pasters, sorry. — zerkms, Jun 25 '14 at 11:57
For each element a[i], initialise a row with a.length zeroes and update the value at the i'th index. — Ja͢ck, Jun 25 '14 at 11:59

score 0 · Answer 1 · answered Jun 25 '14 at 12:19

To create a diagonal matrix from a vector with math.js, you can use the function math.diag. First though you will have to turn your input matrix into a vector, something like:

var A = [[8], [7], [3], [1]];
var B = math.transpose(A); // B = [[8, 7, 3, 1]]
var C = math.squeeze(B);   // C = [8, 7, 3, 1]
var D = math.diag(C);      // D = [[8,0,0,0], [0,7,0,0],[0,0,3,0], [0,0,0,1]]

What code can be used to create a diagonal matrix in javascript

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