MultiSim#

class MultiSim(sims=None, base_sim=None, label=None, initialize=False, **kwargs)[source]#

Bases: FlexPretty

Class for running multiple copies of a simulation. The parameter n_runs controls how many copies of the simulation there will be, if a list of sims is not provided. This is the main class that’s used to run multiple versions of a simulation (e.g., with different random seeds).

Parameters:

  • sims (Sim/list) – a single sim or a list of sims

  • base_sim (Sim) – the sim used for shared properties; if not supplied, the first of the sims provided

  • label (str) – the name of the multisim

  • initialize (bool) – whether or not to initialize the sims (otherwise, initialize them during run)

  • kwargs (dict) – stored in run_args and passed to run()

Returns:

a MultiSim object

Return type:

msim

Examples:

sim = cv.Sim() # Create the sim
msim = cv.MultiSim(sim, n_runs=5) # Create the multisim
msim.run() # Run them in parallel
msim.combine() # Combine into one sim
msim.plot() # Plot results

sim = cv.Sim() # Create the sim
msim = cv.MultiSim(sim, n_runs=11, noise=0.1, keep_people=True) # Set up a multisim with noise
msim.run() # Run
msim.reduce() # Compute statistics
msim.plot() # Plot

sims = [cv.Sim(beta=0.015*(1+0.02*i)) for i in range(5)] # Create sims
for sim in sims: sim.run() # Run sims in serial
msim = cv.MultiSim(sims) # Convert to multisim
msim.plot() # Plot as single sim

Methods

result_keys()[source]#

Attempt to retrieve the results keys from the base sim

init_sims(**kwargs)[source]#

Initialize the sims, but don’t actually run them. Syntax is the same as MultiSim.run(). Note: in most cases you can just call run() directly, there is no need to call this separately.

Parameters:

kwargs (dict) – passed to multi_run()

run(reduce=False, combine=False, **kwargs)[source]#

Run the actual sims

Parameters:

  • reduce (bool) – whether or not to reduce after running (see reduce())

  • combine (bool) – whether or not to combine after running (see combine(), not compatible with reduce)

  • kwargs (dict) – passed to multi_run(); use run_args to pass arguments to sim.run()

Returns:

None (modifies MultiSim object in place)

Examples:

msim.run()
msim.run(run_args=dict(until='2020-0601', restore_pars=False))
shrink(**kwargs)[source]#

Not to be confused with reduce(), this shrinks each sim in the msim; see sim.shrink() for more information.

Parameters:

kwargs (dict) – passed to sim.shrink() for each sim

reset()[source]#

Undo a combine() or reduce() by resetting the base sim, which, and results

reduce(quantiles=None, use_mean=False, bounds=None, output=False)[source]#

Combine multiple sims into a single sim statistically: by default, use the median value and the 10th and 90th percentiles for the lower and upper bounds. If use_mean=True, then use the mean and ±2 standard deviations for lower and upper bounds.

Parameters:

  • quantiles (dict) – the quantiles to use, e.g. [0.1, 0.9] or {‘low : ‘0.1, ‘high’ : 0.9}

  • use_mean (bool) – whether to use the mean instead of the median

  • bounds (float) – if use_mean=True, the multiplier on the standard deviation for upper and lower bounds (default 2)

  • output (bool) – whether to return the “reduced” sim (in any case, modify the multisim in-place)

Example:

msim = cv.MultiSim(cv.Sim())
msim.run()
msim.reduce()
msim.summarize()
mean(bounds=None, **kwargs)[source]#

Alias for reduce(use_mean=True). See reduce() for full description.

Parameters:

  • bounds (float) – multiplier on the standard deviation for the upper and lower bounds (default, 2)

  • kwargs (dict) – passed to reduce()

median(quantiles=None, **kwargs)[source]#

Alias for reduce(use_mean=False). See reduce() for full description.

Parameters:

  • quantiles (list or dict) – upper and lower quantiles (default, 0.1 and 0.9)

  • kwargs (dict) – passed to reduce()

combine(output=False)[source]#

Combine multiple sims into a single sim with scaled results.

Example:

msim = cv.MultiSim(cv.Sim())
msim.run()
msim.combine()
msim.summarize()
compare(t=None, sim_inds=None, output=False, do_plot=False, **kwargs)[source]#

Create a dataframe compare sims at a single point in time.

Parameters:

  • t (int/str) – the day (or date) to do the comparison; default, the end

  • sim_inds (list) – list of integers of which sims to include (default: all)

  • output (bool) – whether or not to return the comparison as a dataframe

  • do_plot (bool) – whether or not to plot the comparison (see also plot_compare())

  • kwargs (dict) – passed to plot_compare()

Returns:

a dataframe comparison

Return type:

df (dataframe)

plot(to_plot=None, inds=None, plot_sims=False, color_by_sim=None, max_sims=5, colors=None, labels=None, alpha_range=None, plot_args=None, show_args=None, **kwargs)[source]#

Plot all the sims – arguments passed to Sim.plot(). The behavior depends on whether or not combine() or reduce() has been called. If so, this function by default plots only the combined/reduced sim (which you can override with plot_sims=True). Otherwise, it plots a separate line for each sim.

Note that this function is complex because it aims to capture the flexibility of both sim.plot() and scens.plot(). By default, if combine() or reduce() has been used, it will resemble sim.plot(); otherwise, it will resemble scens.plot(). This can be changed via color_by_sim, together with the other options.

Parameters:

  • to_plot (list) – list or dict of which results to plot; see cv.get_default_plots() for structure

  • inds (list) – if not combined or reduced, the indices of the simulations to plot (if None, plot all)

  • plot_sims (bool) – whether to plot individual sims, even if combine() or reduce() has been used

  • color_by_sim (bool) – if True, set colors based on the simulation type; otherwise, color by result type; True implies a scenario-style plotting, False implies sim-style plotting

  • max_sims (int) – maximum number of sims to use with color-by-sim; can be overridden by other options

  • colors (list) – if supplied, override default colors for color_by_sim

  • labels (list) – if supplied, override default labels for color_by_sim

  • alpha_range (list) – a 2-element list/tuple/array providing the range of alpha values to use to distinguish the lines

  • plot_args (dict) – passed to sim.plot()

  • show_args (dict) – passed to sim.plot()

  • kwargs (dict) – passed to sim.plot()

Returns:

Figure handle

Return type:

fig

Examples:

sim = cv.Sim()
msim = cv.MultiSim(sim)
msim.run()
msim.plot() # Plots individual sims
msim.reduce()
msim.plot() # Plots the combined sim
plot_result(key, colors=None, labels=None, *args, **kwargs)[source]#

Convenience method for plotting – arguments passed to sim.plot_result()

plot_compare(t=-1, sim_inds=None, log_scale=True, **kwargs)[source]#

Plot a comparison between sims, using bars to show different values for each result. For an explanation of other available arguments, see Sim.plot().

Parameters:

  • t (int) – index of results, passed to compare()

  • sim_inds (list) – which sims to include, passed to compare()

  • log_scale (bool) – whether to plot with a logarithmic x-axis

  • kwargs (dict) – standard plotting arguments, see Sim.plot() for explanation

Returns:

Figure handle

Return type:

fig

save(filename=None, keep_people=False, **kwargs)[source]#

Save to disk as a gzipped pickle. Load with cv.load(filename) or cv.MultiSim.load(filename).

Parameters:

  • filename (str) – the name or path of the file to save to; if None, uses default

  • keep_people (bool) – whether or not to store the population in the Sim objects (NB, very large)

  • kwargs (dict) – passed to sc.makefilepath()

Returns:

the validated absolute path to the saved file

Return type:

scenfile (str)

Example:

msim.save() # Saves to an .msim file
static load(msimfile, *args, **kwargs)[source]#

Load from disk from a gzipped pickle.

Parameters:

  • msimfile (str) – the name or path of the file to load from

  • kwargs – passed to cv.load()

Returns:

the loaded MultiSim object

Return type:

msim (MultiSim)

Example:

msim = cv.MultiSim.load('my-multisim.msim')
static merge(*args, base=False)[source]#

Convenience method for merging two MultiSim objects.

Parameters:

  • args (MultiSim) – the MultiSims to merge (either a list, or separate)

  • base (bool) – if True, make a new list of sims from the multisim’s two base sims; otherwise, merge the multisim’s lists of sims

Returns:

a new MultiSim object

Return type:

msim (MultiSim)

Examples:

mm1 = cv.MultiSim.merge(msim1, msim2, base=True) mm2 = cv.MultiSim.merge([m1, m2, m3, m4], base=False)

split(inds=None, chunks=None)[source]#

Convenience method for splitting one MultiSim into several. You can specify either individual indices of simulations to extract, via inds, or consecutive chunks of indices, via chunks. If this function is called on a merged MultiSim, the chunks can be retrieved automatically and no arguments are necessary.

Parameters:

  • inds (list) – a list of lists of indices, with each list turned into a MultiSim

  • chunks (int or list) – if an int, split the MultiSim into that many chunks; if a list return chunks of that many sims

Returns:

A list of MultiSim objects

Examples:

m1 = cv.MultiSim(cv.Sim(label='sim1'), initialize=True)
m2 = cv.MultiSim(cv.Sim(label='sim2'), initialize=True)
m3 = cv.MultiSim.merge(m1, m2)
m3.run()
m1b, m2b = m3.split()

msim = cv.MultiSim(cv.Sim(), n_runs=6)
msim.run()
m1, m2 = msim.split(inds=[[0,2,4], [1,3,5]])
mlist1 = msim.split(chunks=[2,4]) # Equivalent to inds=[[0,1], [2,3,4,5]]
mlist2 = msim.split(chunks=2) # Equivalent to inds=[[0,1,2], [3,4,5]]
disp(output=False)[source]#

Display a verbose description of a multisim. See also multisim.summarize() (medium length output) and multisim.brief() (short output).

Parameters:

output (bool) – if true, return a string instead of printing output

Example:

msim = cv.MultiSim(cv.Sim(verbose=0), label='Example multisim')
msim.run()
msim.disp() # Displays detailed output
summarize(output=False)[source]#

Print a moderate length summary of the MultiSim. See also multisim.disp() (detailed output) and multisim.brief() (short output).

Parameters:

output (bool) – if true, return a string instead of printing output

Example:

msim = cv.MultiSim(cv.Sim(verbose=0), label='Example multisim')
msim.run()
msim.summarize() # Prints moderate length output
brief(output=False)[source]#

Print a compact representation of the multisim. See also multisim.disp() (detailed output) and multisim.summarize() (medium length output).

Parameters:

output (bool) – if true, return a string instead of printing output

Example:

msim = cv.MultiSim(cv.Sim(verbose=0), label='Example multisim')
msim.run()
msim.brief() # Prints one-line output
to_json(*args, **kwargs)[source]#

Shortcut for base_sim.to_json()

to_excel(*args, **kwargs)[source]#

Shortcut for base_sim.to_excel()