How to import existed data

[TerenceLiu98]

Hi! I am using CUDA to accelerate the computing. However, by using CGBN, how could I import existed data generated by previous code, like I have already generated a 1024-bits number by using GMP Lib as mpz_t.
Also, if there is a sequence ${m_i}$, how can I do the opertion like $m_i + m_{i+1}$

Looking forward to your reply!

[nemmart]

Hi Terence -- you'd do it in a couple of steps. 1) mpz_export to export the mpz_t to cpu memory (take a look at from_mpz(...) in samples/utility/cpu_support.h). 2) copy the cpu memory to the GPU using cudaMalloc and cudaMemcpy(...) 3) launch your GPU kernel and use cgbn_load(...) to load up the data.

In terms of computing a sequence, you'd have to give me some more detail about what exactly you're trying to compute. But samples/sample_03_powm essentially computes a sequence.

Good luck,
Niall

[TerenceLiu98]

Thanks a lot! I have already figure out how to solve the second problem: I could just shift the position and let it become two sequence and do the addition inside the GPU. And, I would try mpz_export as you mentioned. 😃

[TerenceLiu98]

@nemmart Actually, one more question, it is about the xmp library: When I import Integer by using xmpIntegersImport I found that the char * I would like to import's size is 16, but the output's size is only 4, How can I fix it ?
The error is xmpErrorPrecision

[TerenceLiu98]

Hi Terence -- you'd do it in a couple of steps. 1) mpz_export to export the mpz_t to cpu memory (take a look at from_mpz(...) in samples/utility/cpu_support.h). 2) copy the cpu memory to the GPU using cudaMalloc and cudaMemcpy(...) 3) launch your GPU kernel and use cgbn_load(...) to load up the data.

In terms of computing a sequence, you'd have to give me some more detail about what exactly you're trying to compute. But samples/sample_03_powm essentially computes a sequence.

Good luck,
Niall

In CGBN, it has a concept called instance, the number I would like to import should inside the instance or I could just leave it outside fo the instance?

Looking forward to your reply!