Remove unused ptr and associated free

[jeanlucf22]

I found a few pointers that were never used, expect in calls to free them. Not sure if it leads to memory errors, but triggers some warnings from valgrind

[xiaoyeli]

@jeanlucf22 Thanks for providing these fixes.
I reviewed them, your fixes look correct. However, these are all on GPU side, perhaps it won't solve your problem with corrected "B" and "X", which is on CPU.

@piyush314 : can you please review these fixes? If they look correct to you, I can merge the pull request.

Thanks.
Sherry

[xiaoyeli]

@jeanlucf22
We review this, and I merged the PR. Thanks.