Implement differentiation time statistics upon setting clang -ftime-report

[vgvassilev]

The -ftime-report flag in clang enables several timers that produce statistics about how much time the compiler spent in each major compilation phase. If that flag is set and if clad is attached we should print out stats about differentiation times.

[DeadSpheroid]

Hi, id love to work on this issue,
is this the kind of output thats expected?

===-------------------------------------------------------------------------===
                             Timers for clad funcs
===-------------------------------------------------------------------------===
  Total Execution Time: 0.0306 seconds (0.0320 wall clock)

   ---User Time---   --System Time--   --User+System--   ---Wall Time---  --- Name ---
   0.0257 ( 84.0%)   0.0000 (100.0%)   0.0257 ( 84.0%)   0.0271 ( 84.7%)  fn
   0.0049 ( 16.0%)   0.0000 (  0.0%)   0.0049 ( 16.0%)   0.0049 ( 15.3%)  fnr
   0.0306 (100.0%)   0.0000 (100.0%)   0.0306 (100.0%)   0.0320 (100.0%)  Total

===-------------------------------------------------------------------------===
                             Timers for clad funcs
===-------------------------------------------------------------------------===
  Total Execution Time: 0.0073 seconds (0.0073 wall clock)

   ---User Time---   --User+System--   ---Wall Time---  --- Name ---
   0.0073 (100.0%)   0.0073 (100.0%)   0.0073 (100.0%)  fn2
   0.0073 (100.0%)   0.0073 (100.0%)   0.0073 (100.0%)  Total

===-------------------------------------------------------------------------===
                          Pass execution timing report
===-------------------------------------------------------------------------===
  Total Execution Time: 0.0007 seconds (0.0007 wall clock)

   ---User Time---   --User+System--   ---Wall Time---  --- Name ---
   0.0004 ( 54.3%)   0.0004 ( 54.3%)   0.0004 ( 54.2%)  AnnotationRemarksPass
   0.0002 ( 35.2%)   0.0002 ( 35.2%)   0.0002 ( 35.3%)  AlwaysInlinerPass
   0.0001 ( 10.5%)   0.0001 ( 10.5%)   0.0001 ( 10.5%)  CoroConditionalWrapper
   0.0007 (100.0%)   0.0007 (100.0%)   0.0007 (100.0%)  Total

===-------------------------------------------------------------------------===
                        Analysis execution timing report
===-------------------------------------------------------------------------===
  Total Execution Time: 0.0002 seconds (0.0002 wall clock)

   ---User Time---   --User+System--   ---Wall Time---  --- Name ---
   0.0001 ( 72.8%)   0.0001 ( 72.8%)   0.0001 ( 72.7%)  TargetLibraryAnalysis

where fn and fn2 are the differentiated functions in the source file

#include "clad/Differentiator/Differentiator.h"
#include <iostream>
double fnr(double c){
  return c*3*c;
}

double fn(double x, double y) {
  return x*x*x*x + 2*y*fnr(y);
}

double fn2(double a, double b) {
  return 3*a*a + b * b * b;
}


int main() {
  // differentiate 'fn' w.r.t 'x'.
  auto d_fn_1 = clad::differentiate(fn, "x");
  auto d_fn_2 = clad::differentiate(fn2, "a");

  // computes derivative of 'fn' w.r.t 'x' when (x, y) = (3, 4).
  std::cout<<d_fn_1.execute(3, 4)<<"\n";
  std::cout<<d_fn_2.execute(2, 4)<<"\n";
  return 0;
}

[vgvassilev]

Yes, that looks good. Maybe we should have a single Timers for clad funcs section with all functions being differentiated.