star-mc

Parallel estimation of Monte Carlo integrators
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test_smc_doubleN.c (3544B)


      1 /* Copyright (C) 2015-2018, 2021-2023 |Méso|Star> (contact@meso-star.com)
      2  *
      3  * This program is free software: you can redistribute it and/or modify
      4  * it under the terms of the GNU General Public License as published by
      5  * the Free Software Foundation, either version 3 of the License, or
      6  * (at your option) any later version.
      7  *
      8  * This program is distributed in the hope that it will be useful,
      9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
     10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
     11  * GNU General Public License for more details.
     12  *
     13  * You should have received a copy of the GNU General Public License
     14  * along with this program. If not, see <http://www.gnu.org/licenses/>. */
     15 
     16 #include "smc.h"
     17 #include "test_smc_utils.h"
     18 
     19 #include <star/ssp.h>
     20 
     21 #include <math.h>
     22 
     23 enum {
     24   WEIGHT,
     25   WEIGHT_SENSIBILITY_ALPHA,
     26   WEIGHTS_COUNT
     27 };
     28 
     29 struct alpha { double value; };
     30 
     31 static res_T
     32 cos_x
     33   (void* value,
     34    struct ssp_rng* rng,
     35    const unsigned ithread,
     36    const uint64_t irealisation,
     37    void* context)
     38 {
     39   double* result = SMC_DOUBLEN(value);
     40   double samp;
     41   struct smc_doubleN_context* ctx = context;
     42   const struct alpha* alpha = ctx->integrand_data;
     43   (void)ithread, (void)irealisation;
     44   CHK(value != NULL);
     45   CHK(rng != NULL);
     46   samp = ssp_rng_uniform_double(rng, -PI/4.0, PI/4.0);
     47 
     48   result[WEIGHT] = cos(alpha->value*samp) * PI / 2.0;
     49   result[WEIGHT_SENSIBILITY_ALPHA] = -samp * sin(alpha->value*samp) * PI/2.0;
     50 
     51   return RES_OK;
     52 }
     53 
     54 int
     55 main(int argc, char** argv)
     56 {
     57   struct mem_allocator allocator;
     58   struct smc_device* dev;
     59   struct smc_device_create_args args = SMC_DEVICE_CREATE_ARGS_DEFAULT;
     60   struct smc_integrator integrator = SMC_INTEGRATOR_NULL;
     61   struct smc_estimator* estimator;
     62   struct smc_estimator_status status;
     63   struct smc_doubleN_context ctx;
     64   struct alpha alpha;
     65   const double a = 0.4;
     66   double result;
     67   (void)argc, (void)argv;
     68 
     69   mem_init_proxy_allocator(&allocator, &mem_default_allocator);
     70 
     71   args.allocator = &allocator;
     72   CHK(smc_device_create(&args, &dev) == RES_OK);
     73 
     74   integrator.integrand = cos_x;
     75   integrator.type = &smc_doubleN;
     76   integrator.max_realisations = 100000;
     77   alpha.value = a;
     78   ctx.count = WEIGHTS_COUNT;
     79   ctx.integrand_data = &alpha;
     80 
     81   CHK(smc_solve(dev, &integrator, NULL, &estimator) == RES_MEM_ERR);
     82   ctx.count = 0;
     83   CHK(smc_solve(dev, &integrator, &ctx, &estimator) == RES_MEM_ERR);
     84   ctx.count = WEIGHTS_COUNT;
     85   CHK(smc_solve(dev, &integrator, &ctx, &estimator) == RES_OK);
     86   CHK(smc_estimator_get_status(estimator, &status) == RES_OK);
     87 
     88   /* Check the estimated result */
     89   result = 2*sin(a*PI/4.0) / a;
     90   printf("Integral[-PI/4, PI/4] cos(%g*x) dx = %g ~ %g +/- %g\n",
     91      a, result,
     92      SMC_DOUBLEN(status.E)[WEIGHT],
     93      SMC_DOUBLEN(status.SE)[WEIGHT]);
     94   CHK(eq_eps
     95     (result,
     96      SMC_DOUBLEN(status.E)[WEIGHT],
     97      SMC_DOUBLEN(status.SE)[WEIGHT]));
     98 
     99   /* Check the estimated sensibility in alpha */
    100   result = 2*(a*PI/4.0*cos(a*PI/4.0) - sin(a*PI/4.0)) / (a*a);
    101   printf("Integral'[-PI/4, PI/4] cos(%g*x) dx = %g ~ %g +/- %g\n",
    102      a, result,
    103      SMC_DOUBLEN(status.E)[WEIGHT_SENSIBILITY_ALPHA],
    104      SMC_DOUBLEN(status.SE)[WEIGHT_SENSIBILITY_ALPHA]);
    105   CHK(eq_eps
    106     (result,
    107      SMC_DOUBLEN(status.E)[WEIGHT_SENSIBILITY_ALPHA],
    108      SMC_DOUBLEN(status.SE)[WEIGHT_SENSIBILITY_ALPHA]));
    109 
    110   CHK(smc_estimator_ref_put(estimator) == RES_OK);
    111   CHK(smc_device_ref_put(dev) == RES_OK);
    112 
    113   check_memory_allocator(&allocator);
    114   mem_shutdown_proxy_allocator(&allocator);
    115   CHK(mem_allocated_size() == 0);
    116   return 0;
    117 }