[ADOL-C] trace_on with keep=1

[Antoine De Blois]

Hi again,

Please have a look at the attached code. I reproduced the memory leak with keep=1.

So is there a way to "flush" the Taylor stack at a given point? For us, keep=1 helps to speed-up the process, so I'd like to keep the keep=1!!
Best,
Antoine


De : adol-c-bounces at list.coin-or.org [mailto:adol-c-bounces at list.coin-or.org] De la part de Antoine De Blois
Envoyé : Friday, April 10, 2015 3:31 PM
À : adol-c at list.coin-or.org
Cc : Patrice Castonguay
Objet : [ADOL-C] trace_on with keep=1

Hi everyone,

Quick question regarding the usage of keep=1 while creating the tape. Would the following snippet create the memory leak:

int keep = 1;
while (1)
{
  trace_on(0,keep);
// <<= operations
// ...
// ==> operations
trace_off();
jacobian(...);
}

I was assuming that since the tag number remains 0, then the Taylor stack would be overwritten. Is that correct?

I am currently observing a RAM increase with our code when using ADOL-C and trying to figure out its origin. We are using ADOL-C in a CFD adjoint design optimization process, in which the code constantly computes jacobians for different geometries.

I launched valgrind on the side, but since the application uses MPI, valgrind outputs many "false positives"...
Thank you for your time,
Antoine

De : adol-c-bounces at list.coin-or.org<mailto:adol-c-bounces at list.coin-or.org> [mailto:adol-c-bounces at list.coin-or.org]<mailto:[mailto:adol-c-bounces at list.coin-or.org]> De la part de Ralf Juengling
Envoyé : Tuesday, April 07, 2015 4:33 PM
À : adol-c at list.coin-or.org<mailto:adol-c at list.coin-or.org>
Objet : [ADOL-C] Can ADOL-C handle FFTs?

I would like to use ADOL-C for a problem Y = C(X) where the implementation of C uses FFT routines and I want ADOL-C to give me the gradient of C wrt X.

I did a quick trial using the pyadolc Python wrapper and that failed. Before I play around further, could someone tell me if ADOL-C can handle FFTs at all? If not, can any automatic differentiation tool do this?

Thanks,
Ralf

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