added info about sec_cutoff to the documentation

[gsuarezr]

Description
I added a note at the end of the time independent Bloch-Redfield equation section, to indicate that one can simulate the nonsecular version using the sec_cutoff keyword

[Ericgig]

Could you fix the git diff issue. We can't see your changes like this.

[gsuarezr]

Hi Eric, I would love to but I simply don't know what the git diff issue is, might it be that only the file that I modified should show in the diff?

[Ericgig]

Yes, only the files you modified should appear in the diff, right now it seems like your PR changed 256 files, but the files seems to have the same content... If we can't easily see what changed, we can't review the PR.
I am not sure how this happen or how to fix it...

[gsuarezr]

Thanks for clearing that, I'm also not sure how that happened, but it should be fixed now

[Ericgig]

Thank you for the contribution.

The example should be in a code block.
Could you fix format (2 spaces between words, missing capitalization, ...).

[coveralls]

Coverage: 75.317% (-0.01%) from 75.328% when pulling 4d194ae on mcditoos:gsocApp into ab6a0d7 on qutip:master.

[gsuarezr]

Thanks for your feedback, I think it should be better now

[Ericgig]

@nwlambert could you confirm that the addition is exact?
I am not sure that "partial secular approximation" is a good explanation.

[nwlambert]

seems ok, perhaps just referencing how sec_cutoff relates to the condition mentioned above equation 4 in the documentation would make it more precise?

[gsuarezr]

Hi, I added the reference to the equation. I wanted to be more specific but couldn't figure out from the code if the cutoff is something like $|w_{ac}-w_{cd}| \lt cutoff w_{0}$ or without $w_{0}$

[Ericgig]

Let's just fix the spacing in the code and it will be ready to merge.

[gsuarezr]

Sorry for taking this long to reply, I was on holiday. Should be ready now, thanks !