Profiling and debugging

Profiling

One of the main reasons people don’t use ABMs is because they can be very slow. While “vanilla Starsim” is quite fast (10,000 agents running for 100 timesteps should take about a second), custom modules, if not properly written, can be quite slow.

The first step of fixing a slow module is to identify the problem. To do this, Starsim includes some built-in profiling tools.

Let’s look at a simple simulation:

import sciris as sc
import starsim as ss
sc.options(jupyter=True)

pars = dict(
    start = '2000-01-01',
    stop = '2020-01-01',
    diseases = 'sis',
    networks = 'random'
)

# Profile sim
sim = ss.Sim(pars)
prof = sim.profile()
Initializing sim with 10000 agents

Profiling 15 function(s):

 <bound method Sim.run of Sim(n=10000; 2000.01.01—2020.01.01; networks=randomnet; diseases=sis)>

<bound method Sim.start_step of Sim(n=10000; 2000.01.01—2020.01.01; networks=randomnet; diseases=sis [...]

<function Module.start_step at 0x734dd522b9c0>

<function Module.start_step at 0x734dd522b9c0>

<bound method SIS.step_state of sis(pars=[init_prev, beta, dur_inf, waning, imm_boost, _n_initial_ca [...]

<bound method DynamicNetwork.step of randomnet(n_edges=50000; pars=[n_contacts, dur, beta]; states=[ [...]

<bound method Infection.step of sis(pars=[init_prev, beta, dur_inf, waning, imm_boost, _n_initial_ca [...]

<bound method People.step_die of People(n=10000; age=30.0±17.3)>

<bound method People.update_results of People(n=10000; age=30.0±17.3)>

<bound method Network.update_results of randomnet(n_edges=50000; pars=[n_contacts, dur, beta]; state [...]

<function SIS.update_results at 0x734dd4bf0860>

<function Module.finish_step at 0x734dd522bba0>

<function Module.finish_step at 0x734dd522bba0>

<bound method People.finish_step of People(n=10000; age=30.0±17.3)>

<bound method Sim.finish_step of Sim(n=10000; 2000.01.01—2020.01.01; networks=randomnet; diseases=si [...] 




  Running 2000.01.01 ( 0/21) (0.00 s)  ———————————————————— 5%


  Running 2010.01.01 (10/21) (0.23 s)  ••••••••••—————————— 52%


  Running 2020.01.01 (20/21) (0.27 s)  •••••••••••••••••••• 100%



Elapsed time: 0.280 s





——————————————————————————————————————————————————————————————————————

Profile of networks.Network.update_results: 0.000231578 s (0.0827615%)

——————————————————————————————————————————————————————————————————————



Total time: 0.000231578 s

File: /home/cliffk/idm/starsim/starsim/networks.py

Function: update_results at line 256



Line #      Hits         Time  Per Hit   % Time  Line Contents

==============================================================

   256                                               def update_results(self):

   257                                                   """ Store the number of edges in the network """

   258        21     227181.0  10818.1     98.1          self.results['n_edges'][self.ti] = len(self)

   259        21       4397.0    209.4      1.9          return







———————————————————————————————————————————————————————————————

Profile of people.People.finish_step: 0.000352856 s (0.126104%)

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Total time: 0.000352856 s

File: /home/cliffk/idm/starsim/starsim/people.py

Function: finish_step at line 412



Line #      Hits         Time  Per Hit   % Time  Line Contents

==============================================================

   412                                               def finish_step(self):

   413        21     285623.0  13601.1     80.9          self.remove_dead()

   414        21      63322.0   3015.3     17.9          self.update_post()

   415        21       3911.0    186.2      1.1          return







———————————————————————————————————————————————————————————

Profile of people.People.step_die: 0.000493424 s (0.17634%)

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Total time: 0.000493424 s

File: /home/cliffk/idm/starsim/starsim/people.py

Function: step_die at line 375



Line #      Hits         Time  Per Hit   % Time  Line Contents

==============================================================

   375                                               def step_die(self):

   376                                                   """ Carry out any deaths that took place this timestep """

   377        21     375549.0  17883.3     76.1          death_uids = (self.ti_dead <= self.sim.ti).uids

   378        21      34331.0   1634.8      7.0          self.alive[death_uids] = False

   379                                           

   380                                                   # Execute deaths that took place this timestep (i.e., changing the `alive` state of the agents). This is executed

   381                                                   # before analyzers have run so that analyzers are able to inspect and record outcomes for agents that died this timestep

   382        42      56941.0   1355.7     11.5          for disease in self.sim.diseases():

   383        21       7886.0    375.5      1.6              if isinstance(disease, ss.Disease):

   384        21      11104.0    528.8      2.3                  disease.step_die(death_uids)

   385                                           

   386        21       7613.0    362.5      1.5          return death_uids







——————————————————————————————————————————————————————————————————

Profile of people.People.update_results: 0.000978376 s (0.349653%)

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Total time: 0.000978376 s

File: /home/cliffk/idm/starsim/starsim/people.py

Function: update_results at line 404



Line #      Hits         Time  Per Hit   % Time  Line Contents

==============================================================

   404                                               def update_results(self):

   405        21      10157.0    483.7      1.0          ti = self.sim.ti

   406        21       4219.0    200.9      0.4          res = self.sim.results

   407        21     271126.0  12910.8     27.7          res.n_alive[ti] = np.count_nonzero(self.alive)

   408        21     308582.0  14694.4     31.5          res.new_deaths[ti] = np.count_nonzero(self.ti_dead == ti)

   409        21     373968.0  17808.0     38.2          res.cum_deaths[ti] = np.sum(res.new_deaths[:ti]) # TODO: inefficient to compute the cumulative sum on every timestep!

   410        21      10324.0    491.6      1.1          return







————————————————————————————————————————————————————

Profile of diseases.py:670: 0.00132272 s (0.472715%)

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Total time: 0.00132272 s

File: /home/cliffk/idm/starsim/starsim/diseases.py

Function: update_results at line 670



Line #      Hits         Time  Per Hit   % Time  Line Contents

==============================================================

   670                                               @ss.required()

   671                                               def update_results(self):

   672                                                   """ Store the population immunity (susceptibility) """

   673        21     904294.0  43061.6     68.4          super().update_results()

   674        21     412859.0  19660.0     31.2          self.results['rel_sus'][self.ti] = self.rel_sus.mean()

   675        21       5563.0    264.9      0.4          return







——————————————————————————————————————————————————————

Profile of sim.Sim.start_step: 0.00210333 s (0.75169%)

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Total time: 0.00210333 s

File: /home/cliffk/idm/starsim/starsim/sim.py

Function: start_step at line 305



Line #      Hits         Time  Per Hit   % Time  Line Contents

==============================================================

   305                                               def start_step(self):

   306                                                   """ Start the step -- only print progress; all actual changes happen in the modules """

   307                                           

   308                                                   # Set the time and if we have reached the end of the simulation, then do nothing

   309        21       3404.0    162.1      0.2          if self.complete:

   310                                                       errormsg = 'Simulation already complete (call sim.init() to re-run)'

   311                                                       raise AlreadyRunError(errormsg)

   312                                           

   313                                                   # Print out progress if needed

   314        21    1308341.0  62302.0     62.2          self.elapsed = self.timer.toc(output=True)

   315        21       5647.0    268.9      0.3          if self.verbose: # Print progress

   316        21       2410.0    114.8      0.1              t = self.t

   317        21      57381.0   2732.4      2.7              simlabel = f'"{self.label}": ' if self.label else ''

   318        21     571023.0  27191.6     27.1              string = f'  Running {simlabel}{t.now("str")} ({t.ti:2.0f}/{t.npts}) ({self.elapsed:0.2f} s) '

   319        21       4793.0    228.2      0.2              if self.verbose >= 1:

   320                                                           sc.heading(string)

   321        21       3321.0    158.1      0.2              elif self.verbose > 0:

   322        21      12749.0    607.1      0.6                  if not (t.ti % int(1.0 / self.verbose)):

   323         3     120894.0  40298.0      5.7                      sc.progressbar(t.ti + 1, t.npts, label=string, length=20, newline=True)

   324        21      13369.0    636.6      0.6          return







————————————————————————————————————————————————————————————

Profile of diseases.SIS.step_state: 0.00240363 s (0.859011%)

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Total time: 0.00240363 s

File: /home/cliffk/idm/starsim/starsim/diseases.py

Function: step_state at line 631



Line #      Hits         Time  Per Hit   % Time  Line Contents

==============================================================

   631                                               def step_state(self):

   632                                                   """ Progress infectious -> recovered """

   633        21     553840.0  26373.3     23.0          recovered = (self.infected & (self.ti_recovered <= self.ti)).uids

   634        21      46091.0   2194.8      1.9          self.infected[recovered] = False

   635        21      23852.0   1135.8      1.0          self.susceptible[recovered] = True

   636        21    1772016.0  84381.7     73.7          self.update_immunity()

   637        21       7830.0    372.9      0.3          return







——————————————————————————————————————————————————

Profile of modules.py:665: 0.00423679 s (1.51415%)

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Total time: 0.00423679 s

File: /home/cliffk/idm/starsim/starsim/modules.py

Function: start_step at line 665



Line #      Hits         Time  Per Hit   % Time  Line Contents

==============================================================

   665                                               @required()

   666                                               def start_step(self):

   667                                                   """ Tasks to perform at the beginning of the step """

   668        42       9779.0    232.8      0.2          if self.finalized:

   669                                                       errormsg = f'The module {self._debug_name} has already been run. Did you mean to copy it before running it?'

   670                                                       raise RuntimeError(errormsg)

   671        42       8051.0    191.7      0.2          if self.dists is not None: # Will be None if no distributions are defined

   672        42    4202803.0 100066.7     99.2              self.dists.jump_dt() # Advance random number generators forward for calls on this step

   673        42      16157.0    384.7      0.4          return







———————————————————————————————————————————————————————————————

Profile of networks.DynamicNetwork.step: 0.0253281 s (9.05178%)

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Total time: 0.0253281 s

File: /home/cliffk/idm/starsim/starsim/networks.py

Function: step at line 413



Line #      Hits         Time  Per Hit   % Time  Line Contents

==============================================================

   413                                               def step(self):

   414        21    5178577.0 246598.9     20.4          self.end_pairs()

   415        21   20143364.0 959207.8     79.5          self.add_pairs()

   416        21       6194.0    295.0      0.0          return







—————————————————————————————————————————————————————————

Profile of diseases.Infection.step: 0.236692 s (84.5892%)

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Total time: 0.236692 s

File: /home/cliffk/idm/starsim/starsim/diseases.py

Function: step at line 208



Line #      Hits         Time  Per Hit   % Time  Line Contents

==============================================================

   208                                               def step(self):

   209                                                   """

   210                                                   Perform key infection updates, including infection and setting prognoses

   211                                                   """

   212                                                   # Create new cases

   213        21  229577971.0    1e+07     97.0          new_cases, sources, networks = self.infect() # TODO: store outputs in self or use objdict rather than 3 returns

   214                                           

   215                                                   # Set prognoses

   216        21       7046.0    335.5      0.0          if len(new_cases):

   217        21    7098351.0 338016.7      3.0              self.set_outcomes(new_cases, sources)

   218                                           

   219        21       8470.0    403.3      0.0          return new_cases, sources, networks



Figure(672x480)

This graph (which is a shortcut to sim.loop.plot_cpu()) shows us how much time each step in the integration loop takes. We can get line-by-line detail of where each function is taking time, though:

prof.disp(maxentries=5)




——————————————————————————————————————————————————————

Profile of sim.Sim.start_step: 0.00210333 s (0.75169%)

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Total time: 0.00210333 s

File: /home/cliffk/idm/starsim/starsim/sim.py

Function: start_step at line 305



Line #      Hits         Time  Per Hit   % Time  Line Contents

==============================================================

   305                                               def start_step(self):

   306                                                   """ Start the step -- only print progress; all actual changes happen in the modules """

   307                                           

   308                                                   # Set the time and if we have reached the end of the simulation, then do nothing

   309        21       3404.0    162.1      0.2          if self.complete:

   310                                                       errormsg = 'Simulation already complete (call sim.init() to re-run)'

   311                                                       raise AlreadyRunError(errormsg)

   312                                           

   313                                                   # Print out progress if needed

   314        21    1308341.0  62302.0     62.2          self.elapsed = self.timer.toc(output=True)

   315        21       5647.0    268.9      0.3          if self.verbose: # Print progress

   316        21       2410.0    114.8      0.1              t = self.t

   317        21      57381.0   2732.4      2.7              simlabel = f'"{self.label}": ' if self.label else ''

   318        21     571023.0  27191.6     27.1              string = f'  Running {simlabel}{t.now("str")} ({t.ti:2.0f}/{t.npts}) ({self.elapsed:0.2f} s) '

   319        21       4793.0    228.2      0.2              if self.verbose >= 1:

   320                                                           sc.heading(string)

   321        21       3321.0    158.1      0.2              elif self.verbose > 0:

   322        21      12749.0    607.1      0.6                  if not (t.ti % int(1.0 / self.verbose)):

   323         3     120894.0  40298.0      5.7                      sc.progressbar(t.ti + 1, t.npts, label=string, length=20, newline=True)

   324        21      13369.0    636.6      0.6          return







————————————————————————————————————————————————————————————

Profile of diseases.SIS.step_state: 0.00240363 s (0.859011%)

————————————————————————————————————————————————————————————



Total time: 0.00240363 s

File: /home/cliffk/idm/starsim/starsim/diseases.py

Function: step_state at line 631



Line #      Hits         Time  Per Hit   % Time  Line Contents

==============================================================

   631                                               def step_state(self):

   632                                                   """ Progress infectious -> recovered """

   633        21     553840.0  26373.3     23.0          recovered = (self.infected & (self.ti_recovered <= self.ti)).uids

   634        21      46091.0   2194.8      1.9          self.infected[recovered] = False

   635        21      23852.0   1135.8      1.0          self.susceptible[recovered] = True

   636        21    1772016.0  84381.7     73.7          self.update_immunity()

   637        21       7830.0    372.9      0.3          return







——————————————————————————————————————————————————

Profile of modules.py:665: 0.00423679 s (1.51415%)

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Total time: 0.00423679 s

File: /home/cliffk/idm/starsim/starsim/modules.py

Function: start_step at line 665



Line #      Hits         Time  Per Hit   % Time  Line Contents

==============================================================

   665                                               @required()

   666                                               def start_step(self):

   667                                                   """ Tasks to perform at the beginning of the step """

   668        42       9779.0    232.8      0.2          if self.finalized:

   669                                                       errormsg = f'The module {self._debug_name} has already been run. Did you mean to copy it before running it?'

   670                                                       raise RuntimeError(errormsg)

   671        42       8051.0    191.7      0.2          if self.dists is not None: # Will be None if no distributions are defined

   672        42    4202803.0 100066.7     99.2              self.dists.jump_dt() # Advance random number generators forward for calls on this step

   673        42      16157.0    384.7      0.4          return







———————————————————————————————————————————————————————————————

Profile of networks.DynamicNetwork.step: 0.0253281 s (9.05178%)

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Total time: 0.0253281 s

File: /home/cliffk/idm/starsim/starsim/networks.py

Function: step at line 413



Line #      Hits         Time  Per Hit   % Time  Line Contents

==============================================================

   413                                               def step(self):

   414        21    5178577.0 246598.9     20.4          self.end_pairs()

   415        21   20143364.0 959207.8     79.5          self.add_pairs()

   416        21       6194.0    295.0      0.0          return







—————————————————————————————————————————————————————————

Profile of diseases.Infection.step: 0.236692 s (84.5892%)

—————————————————————————————————————————————————————————



Total time: 0.236692 s

File: /home/cliffk/idm/starsim/starsim/diseases.py

Function: step at line 208



Line #      Hits         Time  Per Hit   % Time  Line Contents

==============================================================

   208                                               def step(self):

   209                                                   """

   210                                                   Perform key infection updates, including infection and setting prognoses

   211                                                   """

   212                                                   # Create new cases

   213        21  229577971.0    1e+07     97.0          new_cases, sources, networks = self.infect() # TODO: store outputs in self or use objdict rather than 3 returns

   214                                           

   215                                                   # Set prognoses

   216        21       7046.0    335.5      0.0          if len(new_cases):

   217        21    7098351.0 338016.7      3.0              self.set_outcomes(new_cases, sources)

   218                                           

   219        21       8470.0    403.3      0.0          return new_cases, sources, networks


(Note that the names of the functions here refer to the actual functions called, which may not match the graph above. That’s because, for example, ss.SIS does not define its own step() method, but instead inherits step() from Infection. In the graph, this is shown as sis.step(), but is listed in the table as Infection.step(). This is because it’s referring to the actual code being run, so refers to where those lines of code exist in the codebase; there is no code corresponding to SIS.step() since it’s just inherited from Infection.step().)

If you want more detail, you can also define custom functions to follow. For example, we can see that ss.SIS.infect() takes the most time in ss.SIS.step(), so let’s profile that:

prof = sim.profile(follow=ss.SIS.infect, plot=False)
prof.disp()
Initializing sim with 10000 agents

Profiling 1 function(s):

 <function Infection.infect at 0x734dd4be3420> 




  Running 2000.01.01 ( 0/21) (0.00 s)  ———————————————————— 5%


  Running 2010.01.01 (10/21) (0.04 s)  ••••••••••—————————— 52%


  Running 2020.01.01 (20/21) (0.07 s)  •••••••••••••••••••• 100%



Elapsed time: 82.0 ms





————————————————————————————————————————————————————————————

Profile of diseases.Infection.infect: 0.0366014 s (44.6268%)

————————————————————————————————————————————————————————————



Total time: 0.0366014 s

File: /home/cliffk/idm/starsim/starsim/diseases.py

Function: infect at line 230



Line #      Hits         Time  Per Hit   % Time  Line Contents

==============================================================

   230                                               def infect(self):

   231                                                   """ Determine who gets infected on this timestep via transmission on the network """

   232        21       7646.0    364.1      0.0          new_cases = []

   233        21       3833.0    182.5      0.0          sources = []

   234        21       1635.0     77.9      0.0          networks = []

   235        21     212085.0  10099.3      0.6          betamap = self.validate_beta()

   236                                           

   237        21     578626.0  27553.6      1.6          rel_trans = self.rel_trans.asnew(self.infectious * self.rel_trans)

   238        21     303527.0  14453.7      0.8          rel_sus   = self.rel_sus.asnew(self.susceptible * self.rel_sus)

   239                                           

   240        42      52155.0   1241.8      0.1          for i, (nkey,route) in enumerate(self.sim.networks.items()):

   241        21      10358.0    493.2      0.0              nk = ss.standardize_netkey(nkey)

   242                                           

   243                                                       # Main use case: networks

   244        21       5025.0    239.3      0.0              if isinstance(route, ss.Network):

   245        21      61713.0   2938.7      0.2                  if len(route): # Skip networks with no edges

   246        21       3179.0    151.4      0.0                      edges = route.edges

   247        21      61276.0   2917.9      0.2                      p1p2b0 = [edges.p1, edges.p2, betamap[nk][0]] # Person 1, person 2, beta 0

   248        21      53037.0   2525.6      0.1                      p2p1b1 = [edges.p2, edges.p1, betamap[nk][1]] # Person 2, person 1, beta 1

   249        63      23561.0    374.0      0.1                      for src, trg, beta in [p1p2b0, p2p1b1]:

   250        42      28792.0    685.5      0.1                          if beta: # Skip networks with no transmission

   251        42     487177.0  11599.5      1.3                              disease_beta = beta.to_prob(self.t.dt) if isinstance(beta, ss.Rate) else beta

   252        42    1220398.0  29057.1      3.3                              beta_per_dt = route.net_beta(disease_beta=disease_beta, disease=self) # Compute beta for this network and timestep

   253        42   26205771.0 623946.9     71.6                              randvals = self.trans_rng.rvs(src, trg) # Generate a new random number based on the two other random numbers

   254        42      17873.0    425.5      0.0                              args = (src, trg, rel_trans, rel_sus, beta_per_dt, randvals) # Set up the arguments to calculate transmission

   255        42    5888228.0 140195.9     16.1                              target_uids, source_uids = self.compute_transmission(*args) # Actually calculate it

   256        42       7603.0    181.0      0.0                              new_cases.append(target_uids)

   257        42       4283.0    102.0      0.0                              sources.append(source_uids)

   258        42     247614.0   5895.6      0.7                              networks.append(np.full(len(target_uids), dtype=ss_int, fill_value=i))

   259                                           

   260                                                       # Handle everything else: mixing pools, environmental transmission, etc.

   261                                                       elif isinstance(route, ss.Route):

   262                                                           # Mixing pools are unidirectional, only use the first beta value

   263                                                           disease_beta = betamap[nk][0].to_prob(self.t.dt) if isinstance(betamap[nk][0], ss.Rate) else betamap[nk][0]

   264                                                           target_uids = route.compute_transmission(rel_sus, rel_trans, disease_beta, disease=self)

   265                                                           new_cases.append(target_uids)

   266                                                           sources.append(np.full(len(target_uids), dtype=ss_float, fill_value=np.nan))

   267                                                           networks.append(np.full(len(target_uids), dtype=ss_int, fill_value=i))

   268                                                       else:

   269                                                           errormsg = f'Cannot compute transmission via route {type(route)}; please subclass ss.Route and define a compute_transmission() method'

   270                                                           raise TypeError(errormsg)

   271                                           

   272                                                   # Finalize

   273        21       7544.0    359.2      0.0          if len(new_cases) and len(sources):

   274        21     132806.0   6324.1      0.4              new_cases = ss.uids.cat(new_cases)

   275        21     791759.0  37702.8      2.2              new_cases, inds = new_cases.unique(return_index=True)

   276        21      94972.0   4522.5      0.3              sources = ss.uids.cat(sources)[inds]

   277        21      49364.0   2350.7      0.1              networks = np.concatenate(networks)[inds]

   278                                                   else:

   279                                                       new_cases = ss.uids()

   280                                                       sources = ss.uids()

   281                                                       networks = np.empty(0, dtype=ss_int)

   282                                           

   283        21      39545.0   1883.1      0.1          return new_cases, sources, networks







————————————————————————————————————————————————————————————

Profile of diseases.Infection.infect: 0.0366014 s (44.6268%)

————————————————————————————————————————————————————————————



Total time: 0.0366014 s

File: /home/cliffk/idm/starsim/starsim/diseases.py

Function: infect at line 230



Line #      Hits         Time  Per Hit   % Time  Line Contents

==============================================================

   230                                               def infect(self):

   231                                                   """ Determine who gets infected on this timestep via transmission on the network """

   232        21       7646.0    364.1      0.0          new_cases = []

   233        21       3833.0    182.5      0.0          sources = []

   234        21       1635.0     77.9      0.0          networks = []

   235        21     212085.0  10099.3      0.6          betamap = self.validate_beta()

   236                                           

   237        21     578626.0  27553.6      1.6          rel_trans = self.rel_trans.asnew(self.infectious * self.rel_trans)

   238        21     303527.0  14453.7      0.8          rel_sus   = self.rel_sus.asnew(self.susceptible * self.rel_sus)

   239                                           

   240        42      52155.0   1241.8      0.1          for i, (nkey,route) in enumerate(self.sim.networks.items()):

   241        21      10358.0    493.2      0.0              nk = ss.standardize_netkey(nkey)

   242                                           

   243                                                       # Main use case: networks

   244        21       5025.0    239.3      0.0              if isinstance(route, ss.Network):

   245        21      61713.0   2938.7      0.2                  if len(route): # Skip networks with no edges

   246        21       3179.0    151.4      0.0                      edges = route.edges

   247        21      61276.0   2917.9      0.2                      p1p2b0 = [edges.p1, edges.p2, betamap[nk][0]] # Person 1, person 2, beta 0

   248        21      53037.0   2525.6      0.1                      p2p1b1 = [edges.p2, edges.p1, betamap[nk][1]] # Person 2, person 1, beta 1

   249        63      23561.0    374.0      0.1                      for src, trg, beta in [p1p2b0, p2p1b1]:

   250        42      28792.0    685.5      0.1                          if beta: # Skip networks with no transmission

   251        42     487177.0  11599.5      1.3                              disease_beta = beta.to_prob(self.t.dt) if isinstance(beta, ss.Rate) else beta

   252        42    1220398.0  29057.1      3.3                              beta_per_dt = route.net_beta(disease_beta=disease_beta, disease=self) # Compute beta for this network and timestep

   253        42   26205771.0 623946.9     71.6                              randvals = self.trans_rng.rvs(src, trg) # Generate a new random number based on the two other random numbers

   254        42      17873.0    425.5      0.0                              args = (src, trg, rel_trans, rel_sus, beta_per_dt, randvals) # Set up the arguments to calculate transmission

   255        42    5888228.0 140195.9     16.1                              target_uids, source_uids = self.compute_transmission(*args) # Actually calculate it

   256        42       7603.0    181.0      0.0                              new_cases.append(target_uids)

   257        42       4283.0    102.0      0.0                              sources.append(source_uids)

   258        42     247614.0   5895.6      0.7                              networks.append(np.full(len(target_uids), dtype=ss_int, fill_value=i))

   259                                           

   260                                                       # Handle everything else: mixing pools, environmental transmission, etc.

   261                                                       elif isinstance(route, ss.Route):

   262                                                           # Mixing pools are unidirectional, only use the first beta value

   263                                                           disease_beta = betamap[nk][0].to_prob(self.t.dt) if isinstance(betamap[nk][0], ss.Rate) else betamap[nk][0]

   264                                                           target_uids = route.compute_transmission(rel_sus, rel_trans, disease_beta, disease=self)

   265                                                           new_cases.append(target_uids)

   266                                                           sources.append(np.full(len(target_uids), dtype=ss_float, fill_value=np.nan))

   267                                                           networks.append(np.full(len(target_uids), dtype=ss_int, fill_value=i))

   268                                                       else:

   269                                                           errormsg = f'Cannot compute transmission via route {type(route)}; please subclass ss.Route and define a compute_transmission() method'

   270                                                           raise TypeError(errormsg)

   271                                           

   272                                                   # Finalize

   273        21       7544.0    359.2      0.0          if len(new_cases) and len(sources):

   274        21     132806.0   6324.1      0.4              new_cases = ss.uids.cat(new_cases)

   275        21     791759.0  37702.8      2.2              new_cases, inds = new_cases.unique(return_index=True)

   276        21      94972.0   4522.5      0.3              sources = ss.uids.cat(sources)[inds]

   277        21      49364.0   2350.7      0.1              networks = np.concatenate(networks)[inds]

   278                                                   else:

   279                                                       new_cases = ss.uids()

   280                                                       sources = ss.uids()

   281                                                       networks = np.empty(0, dtype=ss_int)

   282                                           

   283        21      39545.0   1883.1      0.1          return new_cases, sources, networks


(Note: you can only follow functions that are called as part of sim.run() this way. To follow other functions, such as those run by sim.init(), you can use sc.profile() directly.)

Debugging

When figuring out what your sim is doing – whether it’s doing something it shouldn’t be, or not doing something it should – sim.loop is your friend. It shows everything that will happen in the sim, and in what order:

import starsim as ss

sim = ss.Sim(
    start = 2000,
    stop = 2002,
    diseases = 'sis',
    networks = 'random',
    verbose = 0,
)
sim.run()
sim.loop.df.disp()
# %%
    time  ti  func_order                     label     module       func_name    cpu_time
0   2000   0           0            sim.start_step        sim      start_step  2.5210e-04
1   2000   0           1      randomnet.start_step  randomnet      start_step  1.1996e-04
2   2000   0           2            sis.start_step        sis      start_step  1.1764e-04
3   2000   0           3            sis.step_state        sis      step_state  8.2759e-05
4   2000   0           4            randomnet.step  randomnet            step  1.0215e-03
5   2000   0           5                  sis.step        sis            step  2.1364e-03
6   2000   0           6           people.step_die     people        step_die  2.5730e-05
7   2000   0           7     people.update_results     people  update_results  4.9413e-05
8   2000   0           8  randomnet.update_results  randomnet  update_results  5.8710e-06
9   2000   0           9        sis.update_results        sis  update_results  7.6331e-05
10  2000   0          10     randomnet.finish_step  randomnet     finish_step  2.3270e-06
11  2000   0          11           sis.finish_step        sis     finish_step  1.3260e-06
12  2000   0          12        people.finish_step     people     finish_step  1.8643e-05
13  2000   0          13           sim.finish_step        sim     finish_step  1.2630e-06
14  2001   1           0            sim.start_step        sim      start_step  6.5462e-05
15  2001   1           1      randomnet.start_step  randomnet      start_step  8.9351e-05
16  2001   1           2            sis.start_step        sis      start_step  1.1176e-04
17  2001   1           3            sis.step_state        sis      step_state  6.7983e-05
18  2001   1           4            randomnet.step  randomnet            step  1.0932e-03
19  2001   1           5                  sis.step        sis            step  2.0490e-03
20  2001   1           6           people.step_die     people        step_die  2.4546e-05
21  2001   1           7     people.update_results     people  update_results  4.5267e-05
22  2001   1           8  randomnet.update_results  randomnet  update_results  5.5830e-06
23  2001   1           9        sis.update_results        sis  update_results  6.9516e-05
24  2001   1          10     randomnet.finish_step  randomnet     finish_step  2.5060e-06
25  2001   1          11           sis.finish_step        sis     finish_step  1.2880e-06
26  2001   1          12        people.finish_step     people     finish_step  1.7442e-05
27  2001   1          13           sim.finish_step        sim     finish_step  1.3460e-06
28  2002   2           0            sim.start_step        sim      start_step  1.6292e-04
29  2002   2           1      randomnet.start_step  randomnet      start_step  1.0252e-04
30  2002   2           2            sis.start_step        sis      start_step  1.1532e-04
31  2002   2           3            sis.step_state        sis      step_state  7.2369e-05
32  2002   2           4            randomnet.step  randomnet            step  1.0537e-03
33  2002   2           5                  sis.step        sis            step  1.9432e-03
34  2002   2           6           people.step_die     people        step_die  2.2767e-05
35  2002   2           7     people.update_results     people  update_results  4.3794e-05
36  2002   2           8  randomnet.update_results  randomnet  update_results  5.3820e-06
37  2002   2           9        sis.update_results        sis  update_results  6.3036e-05
38  2002   2          10     randomnet.finish_step  randomnet     finish_step  1.8330e-06
39  2002   2          11           sis.finish_step        sis     finish_step  1.3810e-06
40  2002   2          12        people.finish_step     people     finish_step  1.6210e-05
41  2002   2          13           sim.finish_step        sim     finish_step  1.1220e-06

As you can see, it’s a lot – this is only three timesteps and two modules, and it’s already 41 steps.

The typical way to do debugging is to insert breakpoints or print statements into your modules for custom debugging (e.g., to print a value), or to use analyzers for heavier-lift debugging. Starsim also lets you manually modify the loop by inserting “probes” or other arbitrary functions. For example, if you wanted to check the population size after each time the People object is updated:

def check_pop_size(sim):
    print(f'Population size is {len(sim.people)}')

sim = ss.Sim(diseases='sir', networks='random', demographics=True, dur=10)
sim.init()
sim.loop.insert(check_pop_size, label='people.finish_step')
sim.run()
Initializing sim with 10000 agents
  Running 2000.01.01 ( 0/11) (0.00 s)  •——————————————————— 9%
Population size is 10191
Population size is 10279
Population size is 10377
Population size is 10485
Population size is 10563
Population size is 10651
Population size is 10728
Population size is 10803
Population size is 10901
Population size is 11008
  Running 2010.01.01 (10/11) (0.06 s)  •••••••••••••••••••• 100%

Population size is 11099
Sim(n=10000; 2000—2010; demographics=births, deaths; networks=randomnet; diseases=sir)

In this case, you get the same output as using an analyzer:

def check_pop_size(sim):
    print(f'Population size is {len(sim.people)}')

sim = ss.Sim(diseases='sir', networks='random', demographics=True, dur=10, analyzers=check_pop_size)
sim.run()
Initializing sim with 10000 agents
  Running 2000.01.01 ( 0/11) (0.00 s)  •——————————————————— 9%
Population size is 10191
Population size is 10279
Population size is 10377
Population size is 10485
Population size is 10563
Population size is 10651
Population size is 10728
Population size is 10803
Population size is 10901
Population size is 11008
  Running 2010.01.01 (10/11) (0.06 s)  •••••••••••••••••••• 100%

Population size is 11099
Sim(n=10000; 2000—2010; demographics=births, deaths; networks=randomnet; diseases=sir; analyzers=check_pop_size)

However, inserting functions directly in the loop gives you more control over their exact placement, whereas analyzers are always executed last in the timestep.

The loop also has methods for visualizing itself. You can get a simple representation of the loop with loop.plot():

sim.loop.plot()
Figure(672x480)

Or a slightly more detailed one with loop.plot_step_order():

sim.loop.plot_step_order()
Figure(672x480)

This is especially useful if your simulation has modules with different timesteps, e.g.:

sis = ss.SIS(dt=0.1)
net = ss.RandomNet(dt=0.5)
births = ss.Births(dt=1)
sim = ss.Sim(dt=0.1, dur=5, diseases=sis, networks=net, demographics=births)
sim.init()
sim.loop.plot_step_order()
Initializing sim with 10000 agents
Figure(672x480)

(Note: this is a 3D plot, so it helps if you can plot it in a separate window interactively to be able to move it around, rather than just in a notebook.)