avoid division by zero in svd(::Diagonal)

[araujoms]

Fixes #1149

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.85%. Comparing base (1137b4c) to head (bb5f566).
Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1150      +/-   ##
==========================================
+ Coverage   91.81%   91.85%   +0.03%     
==========================================
  Files          34       34              
  Lines       15342    15342              
==========================================
+ Hits        14087    14092       +5     
+ Misses       1255     1250       -5     

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[jd-foster]

Would it be possible to add a test for this as well?

[araujoms]

Sure.

[dkarrasch]

Is this changing D for all the tests coming after this? I see that tests pass, but perhaps it's better to introduce a small new testset with the example you gave in the original issue:

d = [1, 2, 3, 4, 0]
@test svd(diagm(d)) == svd(Diagonal(d))

?

[araujoms]

Indeed, it is. That was intentional, as the subsequent test was also failing for singular matrices. I thought about doing that when D is generated in the first place, as a zero is more useful test than a random number, but decided against because that would be confusing.

I don't have anything to do with issue, though, I just randomly found it and decided to fix it because it was so easy.

[jishnub]

Looks fine to me, so barring further comments, I would suggest merging.