Updated docs for R-package installation

[piyushghai]

Description

Added a note about having cuDNN installation as a pre-req for running R-packages.

Checklist

Essentials

Please feel free to remove inapplicable items for your PR.

• Changes are complete (i.e. I finished coding on this PR)
• Code is well-documented:
• To the my best knowledge, examples are either not affected by this change, or have been fixed to be compatible with this change

@hetong007 @aaronmarkham

[hetong007]

Do we still support cu80 in 1.4 release?

[piyushghai]

Do we still support cu80 in 1.4 release?

There were issues when I tried to make the packages for cu80.
I was following the steps given here :
http:https://mxnet.incubator.apache.org/versions/master/install/build_from_source.html

[hetong007]

If I recall correctly, you need an earlier version of visual studio to build cu80. Have you tried that?

[piyushghai]

If I recall correctly, you need an earlier version of visual studio to build cu80. Have you tried that?

Yes. I tried with VS 2015 (not 2017). Still did not work.

[hetong007]

@ankkhedia Since you have built cu80 for MXNET R 1.3, would you please help @piyushghai to build cu80? It is helpful for us to go through and fix the configuration, so that we can have a smooth pipeline for the R releases in the future.

[anirudhacharya]

@piyushghai did you get a chance to speak to Ankit about the windows build. I recollect you were working with him on the 1.4 release build.

@mxnet-label-bot add [pr-awaiting-review]

[ankkhedia]

@hetong007 unfortunately, I tried building it for cu80 using VS2015 but was not able to get it working for 1.3

[hetong007]

If 1.4 doesn't come with cu80 binary, don't we want to remove cu80 in the doc?

[piyushghai]

If 1.4 doesn't come with cu80 binary, don't we want to remove cu80 in the doc?

Removed it.

[karan6181]

@piyushghai Thank you for your contribution. Can you please look into this PR? is there any blocker?
Also, Please look at the CI why is it failing?

[abhinavs95]

@hetong007 Could you have a look again and see if your comments are addressed? Thanks

[szha]

@piyushghai thanks for the patch. This PR needs a rebase to the latest master branch. Would you mind?

[piyushghai]

@piyushghai thanks for the patch. This PR needs a rebase to the latest master branch. Would you mind?

Done. :)

[aaronmarkham]

Is this intended to be Windows only?
I see the update here, but for no other OS:
http:https://mxnet-ci-doc.s3-accelerate.dualstack.amazonaws.com/PR-14269/8/install/index.html?platform=Windows&language=R&processor=GPU

[piyushghai]

Is this intended to be Windows only?
I see the update here, but for no other OS:
http:https://mxnet-ci-doc.s3-accelerate.dualstack.amazonaws.com/PR-14269/8/install/index.html?platform=Windows&language=R&processor=GPU

Yes. This particular instruction update is Windows only.