def show_posteriors(self, kde=True):
if hasattr(self, 'burned_trace'):
pm.plots.traceplot(trace=self.burned_trace, varnames=["std", "beta", "alpha"])
pm.plot_posterior(trace=self.burned_trace, varnames=["std", "beta", "alpha"], kde_plot=kde)
pm.plots.autocorrplot(trace=self.burned_trace, varnames=["std", "beta", "alpha"])
else:
print("You must sample from the posteriors first.")
def effect_difference(effect1, effect2, name1, name2, CI=95.0, show=True):
diff = effect1 - effect2
label = str(name1) + ' - ' + str(name2)
plt.figure(figsize=(4, 3))
plt.locator_params(nbins=4)
plt.hist(diff, bins=100, label=label)
plt.legend()
if show: plt.show()
fig = plt.figure(figsize=(3, 3))
plt.locator_params(nbins=4)
ax = fig.gca()
pm.plot_posterior(effect1 - effect2,
varnames=[name1, name2],
ref_val=0,
color='#87ceeb',
ax=ax)
ax.set_title(label)
if show: plt.show()
low_p = (100.0 - CI) / 2.0
high_p = low_p + CI
print(label,
str(CI) + ' CI:', np.percentile(diff, low_p),
np.percentile(diff, high_p), 'Pr > 0:', (diff > 0).mean())
return fig
def do_differences(recalculate=False):
trace_cols = ["duration", "dist_err", "x_err", "y_err", "rms_x", "rms_y"]
trace_coeffs = [[(5, 50), 50]] + [[(0, 2), 0.5]]*5
trace_cols = ["path_length", "move_l", "move_r", "move_x", "move_b",
"move_f", "move_y"]
trace_coeffs = [[(0, 10), 10], [(0, 5), 3], [(0, 5), 3], [(0, 10), 6],
[(0, 5), 1.5], [(0, 5), 7], [(0, 10), 9]]
if recalculate:
traces = analyze_differences(analyses, trace_cols, trace_coeffs)
else:
traces = {col: load_best_result(col) for col in trace_cols}
for col, best_result in traces.items():
trace = best_result.trace
with figure(f"mean_std_{col}"):
ax = pm.plot_posterior(trace[100:],
varnames=[r"group1_mean", r"group2_mean",
r"group1_std", "group2_std"],
kde_plot=True, color="C0")
for a in (1, 3):
ax[a].lines[0].set_color("C1")
with figure(f"difference_{col}"):
pm.plot_posterior(trace[1000:],
varnames=["difference of means", "effect size"],
ref_val=0, kde_plot=True, color="C2")
def summarize(best_result, kde=True, plot=True):
trace, model = best_result
if plot:
ax = pm.plot_posterior(trace[100:],
varnames=[
r"group1_mean", r"group2_mean",
r"group1_std", "group2_std", r"ν_minus_one"
],
kde_plot=kde,
color="C0")
if kde:
for a in (1, 3):
ax[a].lines[0].set_color("C1")
plt.figure()
pm.plot_posterior(trace[1000:],
varnames=[
"difference of means", "difference of stds",
"effect size"
],
ref_val=0,
kde_plot=True,
color="C2")
plt.figure()
pm.forestplot(trace[1000:], varnames=[v.name for v in model.vars[:2]])
plt.figure()
pm.forestplot(trace[1000:], varnames=[v.name for v in model.vars[2:]])
pm.summary(
trace[1000:],
varnames=["difference of means", "difference of stds", "effect size"])
def main():
with pm.Model() as model:
# Using a strong prior. Meaning the mean is towards zero than towards 1
prior = pm.Beta('prior', 0.5, 3)
output = pm.Binomial('output', n=100, observed=50, p=prior)
step = pm.Metropolis()
trace = pm.sample(1000, step=step)
pm.traceplot(trace)
pm.plot_posterior(trace, figsize=(5, 5), kde_plot=True,
rope=[0.45, 0.55]) # Rope is an interval that you define
# This is a value you eppect. You can check
# If ROPE fall on HPD or not. If it falls, it means
# our value is within HPD and may be increasing sample
# size would make our mean estimate better.
# gelman rubin
pm.gelman_rubin(trace)
# forestplot
pm.forestplot(trace, varnames=['prior'])
# summary [look at mc error here. This is the std error, should be low]
pm.df_summary(trace)
#autocorrelation
pm.autocorrplot(trace)
# effective size
pm.effective_n(trace)['prior']
def main():
# Hyperparameters
n_flips = 125
n_coins = 10
n_draws = 5000
n_init_steps = 10000
n_burn_in_steps = 1000
# Create Causal Distribution
causal_probs = np.random.uniform(size=n_coins)
# Create Observations
X = np.array([
np.random.choice(2, p=[1 - p_, p_], size=n_flips)
for i, p_ in enumerate(causal_probs)
]).T
# Create Model
with pm.Model() as model:
ps = pm.Beta('probs', alpha=1, beta=1, shape=n_coins)
components = pm.Bernoulli.dist(p=ps, shape=n_coins)
w = pm.Dirichlet('w', a=np.ones(n_coins))
mix = pm.Mixture('mix', w=w, comp_dists=components, observed=X)
# Train Model
with model:
trace = pm.sample(n_draws, n_init=n_init_steps, tune=n_burn_in_steps)
# Display Results
pm.plot_trace(trace, var_names=['w', 'probs'])
plt.show()
pm.plot_posterior(trace, var_names=['w', 'probs'])
plt.show()
def display_posterior(trace, filename):
prj = project_reader(filename)
WP_NAMES = np.array(prj[1][:, 0])
WP_NUMBER = prj[1][:, 0].shape[0]
PV_names = list()
PVpartial_names = list()
EV_names = list()
COMP_names = list()
SPI_names = list()
CPI_names = list()
Index_names = ["SPI_PROJECT", "CPI_PROJECT", "ETC", "EAC", "TEAC"]
RISK_names = list()
projectDefinition = prj[1]
for x in range(WP_NUMBER):
for y in range(2):
if (projectDefinition[x][y + 1] != 0):
rname = projectDefinition[x][0] + "_Risk_%d" % (y + 1)
RISK_names.append(rname)
for x in range(WP_NUMBER):
PV_names.append("PV_%s" % WP_NAMES[x])
PVpartial_names.append("Partial_PV_%s" % WP_NAMES[x])
EV_names.append("EV_%s" % WP_NAMES[x])
COMP_names.append("COMPLETION_%s" % WP_NAMES[x])
SPI_names.append("SPI_%s" % WP_NAMES[x])
CPI_names.append("CPI_%s" % WP_NAMES[x])
all_names = RISK_names + PV_names + PVpartial_names + EV_names + COMP_names + SPI_names + CPI_names + Index_names
print(
pm.summary(trace,
varnames=all_names,
stat_funcs=[trace_mean, trace_sd, trace_quantiles]))
pm.plot_posterior(trace, varnames=all_names)
def save_mat_fig(trace_array, gtype="traceplot"):
"""
save the traceplot array to an image source
:param trace_array:
:return:
"""
# fig = Figure()
if gtype == "traceplot":
print("ENTER save_traceplot")
pm.traceplot(trace_array, figsize=(12,12))
print("PLT.GCF()")
fig = plt.gcf()
print("FIGURE")
buf = io.BytesIO()
print("BUFF")
fig.savefig(buf, format="png")
data = base64.b64encode(buf.getbuffer()).decode("utf8")
elif gtype == "posterior":
print("ENTER plot_posterior")
pm.plot_posterior(trace_array, figsize=(12,12))
fig = plt.gcf()
buf = io.BytesIO()
fig.savefig(buf, format="png")
data = base64.b64encode(buf.getbuffer()).decode("utf8")
else:
data = []
return "data:image/png;base64,{}".format(data)
def plot_traces(traces, names, show=True):
fig_1 = plt.figure()
plt.locator_params(nbins=4)
for (t, n) in zip(traces, names):
plt.hist(t, bins=100, label=n)
plt.legend()
if show: plt.show()
N = len(traces) + 1
figs = []
for (t, n, i) in zip(traces, names, range(1, N)):
fig = plt.figure(figsize=(3, 3))
plt.locator_params(nbins=4)
ax = fig.gca()
# ax = fig_2.add_subplot(1, N, i)
pm.plot_posterior(t, varnames=[n], color='#87ceeb', ax=ax)
ax.set_title(n)
ax.xaxis.set_major_formatter(FormatStrFormatter('%.2f'))
ax.locator_params(axis='x', nbins=4)
ax.locator_params(axis='y', nbins=1)
figs.append((n, fig))
if show: plt.show()
return fig_1, figs
def main(n, observed):
'''
parameters
--------
n : int
number of trials
observed: int
observed number of success
'''
with pm.Model() as exam_model:
# Week uniform prior for prior
prior = pm.Beta('prior', 0.5, 0.5)
# Bernouli trials modeled using binomial distribution
obs = pm.Binomial('obs', n=n, p=prior, observed=observed)
# plot model design
pm.model_to_graphviz(exam_model)
# Use metropolis hasting for sampling
step = pm.Metropolis()
# sample from the prior distribution to get the posterior
trace = pm.sample(5000, step)
# plot posterior
pm.plot_posterior(trace)
# calculate gelman rubin stats
pm.gelman_rubin(trace)
def fit_model(model):
start = time.time()
with model:
step = pm.NUTS()
trace = pm.sample(2000, step=step, chains=1, cores=1, tune=1000)
print(time.time() - start)
pm.plot_posterior(trace)
pm.traceplot(trace)
def update_bayesian_modeling(mean_upd, var_upd, alpha_upd, beta_upd, inv_a_upd,
inv_b_upd, iv_upd, strategy, stock_price,
strike_price, risk_free, time):
with pm.Model() as update_model:
prior = pm.InverseGamma('bv', inv_a_upd, inv_b_upd)
likelihood = pm.InverseGamma('like',
inv_a_upd,
inv_b_upd,
observed=iv_upd)
with update_model:
# step = pm.Metropolis()
v_trace_update = pm.sample(10000, tune=1000)
#print(v_trace['bv'][:])
trace_update = v_trace_update['bv'][:]
#print(trace)
pm.traceplot(v_trace_update)
plt.show()
pm.autocorrplot(v_trace_update)
plt.show()
pm.plot_posterior(v_trace_update[100:],
color='#87ceeb',
point_estimate='mean')
plt.show()
s = pm.summary(v_trace_update).round(2)
print("\n Summary")
print(s)
a = np.random.choice(trace_update, 10000, replace=True)
ar = []
for i in range(9999):
t = a[i] / 100
ar.append(t)
#print("Bayesian Volatility Values", ar)
op = []
for i in range(9999):
temp = BS_price(strategy, stock_price, strike_price, risk_free, ar[i],
time)
op.append(temp)
#print("Bayesian Option Prices", op)
plt.hist(ar, bins=50)
plt.title("Volatility")
plt.ylabel("Frequency")
plt.show()
plt.hist(op, bins=50)
plt.title("Option Price")
plt.ylabel("Frequency")
plt.show()
return trace_update
def plot_ADVI_posterior(NNInput, ADVIApprox):
if (NNInput.PlotShow):
fig = plt.figure()
pymc3.plot_posterior(ADVIApprox.sample(NNInput.NApproxSamplesADVI),
color='LightSeaGreen')
plt.show()
FigPath = NNInput.PathToOutputFldr + '/ADVI_Posterior.png'
fig.savefig(FigPath)
def plot_posterior(trace, *args, **kwargs):
"""Plot posterior of random variables.
Default behaviour is to plot all random variables.
Variables can be selectively plotted by mentioning them in `var_names` argument.
"""
# convert vector-valued variables into multiple scalars
trace, vectors = disentangle_trace(trace)
# resolve variable names
var_names = resolve_var_names(kwargs.get('var_names'), trace, vectors)
if var_names is not None:
kwargs['var_names'] = var_names
pm.plot_posterior(trace, *args, **kwargs) # `pymc3.traceplot`
def model_pymc(std_prior_lower=100.0, std_prior_upper=1000.0):
with pm.Model() as model:
group_sa_mean = pm.Normal('SA_mean', prior_1.mean(), sd=prior_1.std())
group_me_mean = pm.Normal('ME_mean', prior_2.mean(), sd=prior_2.std())
# std_prior_lower = 100.0
# std_prior_upper = 1000.0 # changed to more accurately reflect the standard deviations here
with model:
group_sa_std = pm.Uniform('SA_std',
lower=std_prior_lower,
upper=std_prior_upper)
group_me_std = pm.Uniform('ME_std',
lower=std_prior_lower,
upper=std_prior_upper)
group_sa = pm.Normal('SA_acts',
mu=group_sa_mean,
sd=group_sa_std,
observed=sa_80s)
group_me = pm.Normal('ME_acts',
mu=group_me_mean,
sd=group_me_std,
observed=me_00s)
diff_of_means = pm.Deterministic('difference of means',
group_sa_mean - group_me_mean)
diff_of_stds = pm.Deterministic('difference of stds',
group_sa_std - group_me_std)
effect_size = pm.Deterministic(
'effect size', diff_of_means / np.sqrt(
(group_sa_std**2 + group_me_std**2) / 2))
with model:
trace = pm.sample(25000, njobs=4)
pm.plot_posterior(trace[3000:],
varnames=['SA_mean', 'ME_mean', 'SA_std', 'ME_std'],
color='#F4953B')
pm.plot_posterior(
trace[3000:],
varnames=['difference of means', 'difference of stds', 'effect size'],
ref_val=0,
color='#87ceeb')
plt.show()
def summary(trace, varnames=None, plot_convergence_stats=False):
pm.plot_posterior(trace, varnames=varnames)
plt.show()
pm.plots.traceplot(trace, varnames=varnames)
plt.show()
pm.plots.forestplot(trace, varnames=varnames)
plt.show()
if plot_convergence_stats:
pm.plots.energyplot(trace)
plt.show()
print(
'Gelman-Rubin ',
max(
np.max(gr_values)
for gr_values in pm.gelman_rubin(trace).values()))
return pm.summary(trace, varnames=varnames)
def dice_bias():
y = np.asarray([20, 21, 17, 19, 17, 30])
k = len(y)
p = 1/k
n = y.sum()
with pm.Model() as dice_model:
# initializes the Dirichlet distribution with a uniform prior:
a = np.ones(k)
theta = pm.Dirichlet("theta", a=a)
# Since theta[5] will hold the posterior probability
# of rolling a 6 we'll compare this to the
# reference value p = 1/6 to determine the amount of bias
# in the die
six_bias = pm.Deterministic("six_bias", theta[k-1] - p)
results = pm.Multinomial("results", n=n, p=theta, observed=y)
dice_trace = pm.sample(draws=1000)
pm.traceplot(dice_trace, combined=True, lines={"theta": p})
axes = pm.plot_posterior(dice_trace,
varnames=["theta"],
ref_val=np.round(p, 3))
for i, ax in enumerate(axes):
ax.set_title(f"{i+1}")
six_bias = dice_trace["six_bias"]
six_bias_perc = len(six_bias[six_bias>0])/len(six_bias)
plt.show()
print(f'P(Six is biased) = {six_bias_perc:.2%}')
def excel_posterior(trace, filename):
#Need to read the data again to set activity number and names
prj = project_reader(filename)
WP_NAMES = np.array(prj[1][:, 0])
WP_NUMBER = prj[1][:, 0].shape[0]
PV_names = list()
PVpartial_names = list()
EV_names = list()
COMP_names = list()
SPI_names = list()
CPI_names = list()
Index_names = ["SPI_PROJECT", "CPI_PROJECT", "ETC", "EAC", "TEAC"]
RISK_names = list()
projectDefinition = prj[1]
for x in range(WP_NUMBER):
for y in range(2):
if (projectDefinition[x][y + 1] != 0):
rname = projectDefinition[x][0] + "_Risk_%d" % (y + 1)
RISK_names.append(rname)
for x in range(WP_NUMBER):
PV_names.append("PV_%s" % WP_NAMES[x])
PVpartial_names.append("Partial_PV_%s" % WP_NAMES[x])
EV_names.append("EV_%s" % WP_NAMES[x])
COMP_names.append("COMPLETION_%s" % WP_NAMES[x])
SPI_names.append("SPI_%s" % WP_NAMES[x])
CPI_names.append("CPI_%s" % WP_NAMES[x])
all_names = RISK_names + PV_names + PVpartial_names + EV_names + COMP_names + SPI_names + CPI_names + Index_names
outputName = filename + "Output.xlsx"
traceName = filename + "Trace.xlsx"
pm.summary(trace,
varnames=all_names,
stat_funcs=[trace_mean, trace_sd,
trace_quantiles]).to_excel(outputName,
sheet_name="Summary")
pm.plot_posterior(trace, varnames=all_names)
pm.trace_to_dataframe(trace).to_excel(traceName, sheet_name="Trace")
def plot_difference_of_means(trace, **kwargs):
"""
Plots a difference of means graph
@param trace a trace object
@param **kwargs keyword arguments for matplotlib
@returns a plot axes with the graph plotted
"""
ps1 = pm.plot_posterior(trace, varnames=['difference of means'],
ref_val=0,
color='#87ceeb', **kwargs)
return ps1
def _plot_posterior(self, betaj, save_path=None, axes_size=4, shape=None,
credible_interval=0.94, color_bad=True, beta0=None):
fig, axes = self._predictor_canvas(self.predictors, axes_size, 1, shape=shape)
if beta0 is None:
beta0 = betaj[0]
betaj = betaj[1:]
pm.plot_posterior(beta0.values, point_estimate='mode', ax=axes[0, 0], color=color)
axes[0, 0].set_xlabel(r'$\beta_0$ (Intercept)', fontdict=f_dict)
axes[0, 0].set_title('', fontdict=f_dict)
columns = self.predictors.columns
for i, (ax, feature) in enumerate(zip(axes.flatten()[1:], columns)):
pm.plot_posterior(betaj[feature].values, point_estimate='mode',
credible_interval=credible_interval, ax=ax, color=color)
ax.set_title('', fontdict=f_dict)
ax.set_xlabel(r'$\beta_{{{}}}$ ({})'.format(i + 1, ' '.join(feature)),
fontdict=f_dict)
if color_bad and not self.is_credible(self.trace['zbetaj'][:, i], credible_interval):
ax.patch.set_facecolor('#FFCCCB')
ax.patch.set_visible(True)
if save_path is not None:
fig.savefig(save_path, transparent=True)
return fig
def applyBayesianSampling(self, final_col_list):
formula = 'G3 ~ ' + ' + '.join([i for i in final_col_list])
print('formula : ', formula)
# Context for the model
with pm.Model() as normal_model:
# Setting the likelihood as a normal distribution
family = pm.glm.families.Normal()
# Creating the model using the family, data and formula
pm.GLM.from_formula(formula, data=self.X_train, family=family)
# Perform Markov Chain Monte Carlo sampling
normal_trace = pm.sample(draws=3000, chains=2, tune=1200, cores=-1)
print(pm.summary(normal_trace))
pm.traceplot(normal_trace)
plt.show()
pm.plot_posterior(normal_trace)
plt.show()
blr_formula = self.bayesianLRFormula(normal_trace)
print('blr_formula :', blr_formula)
return normal_trace, blr_formula
def cmt_example():
obs = {
'n1_Hp_Rp': 519,
'n1_Hp': 10473,
'P_Hp': 0.1561185895315763,
'n_Hp_Rp': 42,
'n_Hn_Rp': 2,
'n_Hp_Rn': 687,
'n_Hn_Rn': 3624
}
trace = sample_heuristic_precision(obs, {'draws': 10000, 'tune': 5000})
pm.plot_posterior(trace, credible_interval=0.94)
pm.plot_posterior(trace, credible_interval=0.99)
help(pm.plot_posterior)
pm.traceplot(trace)
pm.forestplot(trace)
q_samples = trace['q']
np.average(q_samples < 0.03)
def plot_posterior(self, varnames=None, ref_val=None):
"""Generate informative plots form the trace.
Parameters
----------
varnames : iterable of str or None, optional
The model variables to generate plots for (default None).
If None, defaults to all variables.
ref_val: int or float or None, optional
The value to use as reference on the plots (default None).
Generally only relevant for posteriors on differences of means
and standard deviations. For example, if ref_val = 0, a bar will
be placed on the posterior plot at a point corresponding to
zero difference in parameters. If this bar lies within the 95% HPD,
then it is likely that there is no significant difference between
the parameters.
"""
varnames = varnames or self.model_variables
pm.plot_posterior(self.trace,
varnames=varnames,
ref_val=ref_val,
color='#8BCAF1')
def plot_posterior(self,
varnames=["estimate"],
ref_val=np.log2(3),
color="LightSeaGreen",
rope=[-.4, .4],
xlim=[-.5, 2],
suffix=""):
plt.rcParams.update({'font.size': 15, 'figure.figsize': (7, 5)})
pm.plot_posterior(self.trace,
varnames=varnames,
ref_val=ref_val,
color=color,
rope=rope)
plt.title("log2FC Posterior for {}".format(self.p.split(";")[0]))
plt.xlim(xlim)
plt.ylabel("Probability")
plt.savefig(os.path.join(self.plot_dir, "posteriors", "eps",
"{}{}.eps".format(self.p, suffix)),
format='eps',
dpi=900)
plt.savefig(
os.path.join(self.plot_dir, "posteriors", "png",
"{}{}.png".format(self.p, suffix)))
plt.close()
def getAngelRate(data, n_sample=10000, n_chain=3, ax=None):
# データの整理
data_0 = data.query('campaign != 1')
data_1 = data.query('campaign == 1')
d = np.array([[
sum(data_0['angel'] == 0),
sum(data_0['angel'] == 1),
sum(data_0['angel'] == 2)
],
[
sum(data_1['angel'] == 0),
sum(data_1['angel'] == 1),
sum(data_1['angel'] == 2)
]])
weight = np.array([[1.0, 1.0, 1.0], [1.0, 0.0, 2.0]])
# パラメータ推定
with pm.Model() as model:
alpha = [1., 1., 1.] # hyper-parameter of DirichletDist.
pi = pm.Dirichlet('pi', a=np.array(alpha))
for i in np.arange(d.shape[0]):
piw = pi * weight[i]
m = pm.Multinomial('m_%s' % (i),
n=np.sum(d[i]),
p=piw,
observed=d[i])
trace = pm.sample(n_sample, chains=n_chain)
np.savetxt('trace_pi.csv', trace['pi'], delimiter=',')
# Silver
hpd_l, hpd_u = pm.hpd(trace['pi'][:, 1])
print('Silver : 95% HPD : {}-{}'.format(hpd_l, hpd_u))
print('Silver ExpectedValue : {}'.format(trace['pi'][:, 1].mean()))
# Gold
hpd_l, hpd_u = pm.hpd(trace['pi'][:, 2])
print('Gold : 95% HPD : {}-{}'.format(hpd_l, hpd_u))
print('Gold ExpectedValue : {}'.format(trace['pi'][:, 2].mean()))
# save fig
if ax is not None:
pm.plot_posterior(trace['pi'][:, 0], ax=ax[0])
pm.plot_posterior(trace['pi'][:, 1], ax=ax[1])
pm.plot_posterior(trace['pi'][:, 2], ax=ax[2])
ax[0].set_title('Nothing')
ax[1].set_title('SilverAngel')
ax[2].set_title('GoldAngel')
return trace
def run(n=1500):
if n == 'short':
n = 50
print('Model with no censored data (omniscient)')
with omniscient_model:
trace = pm.sample(n)
pm.plot_posterior(trace[-1000:], varnames=['mu', 'sigma'])
plt.show()
print('Imputed censored model')
with imputed_censored_model:
trace = pm.sample(n)
pm.plot_posterior(trace[-1000:], varnames=['mu', 'sigma'])
plt.show()
print('Unimputed censored model')
with unimputed_censored_model:
trace = pm.sample(n)
pm.plot_posterior(trace[-1000:], varnames=['mu', 'sigma'])
plt.show()
def run(n=1500):
if n == 'short':
n = 50
print('Model with no censored data (omniscient)')
with omniscient_model:
trace = pm.sample(n)
pm.plot_posterior(trace[-1000:], varnames=['mu', 'sigma'])
plt.show()
print('Imputed censored model')
with imputed_censored_model:
trace = pm.sample(n)
pm.plot_posterior(trace[-1000:], varnames=['mu', 'sigma'])
plt.show()
print('Unimputed censored model')
with unimputed_censored_model:
trace = pm.sample(n)
pm.plot_posterior(trace[-1000:], varnames=['mu', 'sigma'])
plt.show()
## Plot KDE and sampled values for each parameter.
#pm.traceplot(trace)
model_idx_sample = trace['model_index']
pM1 = sum(model_idx_sample == 0) / len(model_idx_sample)
pM2 = 1 - pM1
plt.figure(figsize=(15, 15))
plt.subplot2grid((3,3), (0,0), colspan=3)
plt.plot(model_idx_sample, label='p(DiffMu|D) = %.3f ; p(SameMu|D) = {:.3f}'.format(pM1, pM2));
plt.xlabel('Step in Markov Chain')
plt.legend(loc='upper right', framealpha=0.75)
count = 0
position = [(1,0), (1,1), (1,2), (2,0), (2,1), (2,2)]
for i in range(0, 4):
mui_sample = trace['mu1'][:,i][model_idx_sample == 0]
for j in range(i+1, 4):
muj_sample = trace['mu1'][:,j][model_idx_sample == 0]
ax = plt.subplot2grid((3,3), position[count])
pm.plot_posterior(mui_sample-muj_sample,
ref_val=0, ax=ax)
plt.title(r'$\mu_{} - \mu_{}$'.format(i+1, j+1))
plt.xlim(-0.3, 0.3)
count += 1
plt.tight_layout()
plt.savefig('Figure_12.5.png')
plt.show()
## Print summary for each trace
#pm.summary(trace)
## Check for mixing and autocorrelation
#pm.autocorrplot(trace, vars =[mu, tau])
## Plot KDE and sampled values for each parameter.
#pm.traceplot(trace)
## Extract chains
muG_sample = trace['muG']
tauG_sample = trace['tauG']
m_sample = trace['m']
d_sample = trace['d']
# Plot the hyperdistributions:
_, ax = plt.subplots(1, 4, figsize=(20, 5))
pm.plot_posterior(muG_sample, bins=30, ax=ax[0])
ax[0].set_xlabel(r'$\mu_g$', fontsize=16)
pm.plot_posterior(tauG_sample, bins=30, ax=ax[1])
ax[1].set_xlabel(r'$\tau_g$', fontsize=16)
pm.plot_posterior(m_sample, bins=30, ax=ax[2])
ax[2].set_xlabel('m', fontsize=16)
pm.plot_posterior(d_sample, bins=30, ax=ax[3])
ax[3].set_xlabel('d', fontsize=16)
plt.tight_layout()
plt.savefig('Figure_15.9.png')
plt.show()
with model1:
theta = pm.Dirichlet("theta", a=alpha, shape=(D, K))
phi = pm.Dirichlet("phi", a=beta, shape=(K, V))
doc = pm.DensityDist('doc', log_lda(theta, phi), observed=data)
with model1:
inference = pm.ADVI()
approx = pm.fit(
n=10000,
method=inference,
callbacks=[pm.callbacks.CheckParametersConvergence(diff='absolute')])
#inference
tr1 = approx.sample(draws=1000)
pm.plots.traceplot(tr1)
pm.plot_posterior(tr1, color='LightSeaGreen')
plt.plot(approx.hist)
'''
With MCMC
'''
with model:
theta = pm.Dirichlet("thetas", a=alpha, shape=(D, K))
phi = pm.Dirichlet("phis", a=beta, shape=(K, V))
z = pm.Categorical("zx", p=theta, shape=(W, D))
w = pm.Categorical("wx",
p=t.reshape(phi[z.T], (D * W, V)),
observed=data.reshape(D * W))
with model:
tr = pm.sample(1000, chains=1)
def bayesian_t(df, val_col, grp_col='regulated',
sig_fac=2, unif_l=0, unif_u=20,
exp_mn=30,
plot_trace=False, plot_ppc=False,
plot_vars=False, plot_diffs=True,
steps=2000, mcmc='metropolis'):
""" Simple Bayesian test for differences between two groups.
Args:
df Dataframe. Must have a column containing values
and a categorical 'regulated' column that is [0, 1]
to define the two groups
val_col Name of the values column
grp_col Name of the categorical column defining the groups
sig_fac Factor applied to std. dev. of pooled data to define
prior std. dev. for group means
unif_l Lower bound for uniform prior on std. dev. of group
means
unif_u Upper bound for uniform prior on std. dev. of group
means
exp_mn Mean of exponential prior for v in Student-T
distribution
plot_trace Whether to plot the MCMC traces
plot_ppc Whether to perform and plot the Posterior Predictive
Check
plot_vars Whether to plot posteriors for variables
plot_diffs Whether to plot posteriors for differences
steps Number of steps to take in MCMC chains
mcmc Sampler to use: ['metropolis', 'slice', 'nuts']
Returns:
Creates plots showing the distribution of differences in
means and variances, plus optional diagnostics. Returns the
MCMC trace
"""
import numpy as np
import pymc3 as pm
import pandas as pd
import seaborn as sn
import matplotlib.pyplot as plt
# Get overall means and s.d.
mean_all = df[val_col].mean()
std_all = df[val_col].std()
# Group data
grpd = df.groupby(grp_col)
# Separate groups
reg_data = grpd.get_group(1)[val_col].values
ureg_data = grpd.get_group(0)[val_col].values
# Setup model
with pm.Model() as model:
# Priors for means of Student-T dists
reg_mean = pm.Normal('regulated_mean', mu=mean_all, sd=std_all*sig_fac)
ureg_mean = pm.Normal('unregulated_mean', mu=mean_all, sd=std_all*sig_fac)
# Priors for std. dev. of Student-T dists
reg_std = pm.Uniform('regulated_std', lower=unif_l, upper=unif_u)
ureg_std = pm.Uniform('unregulated_std', lower=unif_l, upper=unif_u)
# Prior for v of Student-T dists
nu = pm.Exponential('v_minus_one', 1./29.) + 1
# Define Student-T dists
# PyMC3 uses precision = 1 / (sd^2) to define dists rather than std. dev.
reg_lam = reg_std**-2
ureg_lam = ureg_std**-2
reg = pm.StudentT('regulated', nu=nu, mu=reg_mean, lam=reg_lam, observed=reg_data)
ureg = pm.StudentT('unregulated', nu=nu, mu=ureg_mean, lam=ureg_lam, observed=ureg_data)
# Quantities of interest (difference of means and std. devs.)
diff_of_means = pm.Deterministic('difference_of_means', reg_mean - ureg_mean)
diff_of_stds = pm.Deterministic('difference_of_stds', reg_std - ureg_std)
# Run sampler to approximate posterior
if mcmc == 'metropolis':
trace = pm.sample(steps, step=pm.Metropolis())
elif mcmc == 'slice':
trace = pm.sample(steps, step=pm.Slice())
elif mcmc == 'nuts':
trace = pm.sample(steps)
else:
raise ValueError("mcmc must be one of ['metropolis', 'slice', 'nuts']")
# Plot results
# Raw data
fig, axes = plt.subplots(nrows=1, ncols=2, figsize=(14,4))
for name, grp in grpd:
sn.distplot(grp[val_col].values, ax=axes[name], kde=False)
axes[name].set_title('Regulated = %s' % name)
# Traces
if plot_trace:
pm.traceplot(trace)
# Posteriors for variables
if plot_vars:
pm.plot_posterior(trace[1000:],
varnames=['regulated_mean', 'unregulated_mean',
'regulated_std', 'unregulated_std'],
alpha=0.3)
# Posteriors for differences
if plot_diffs:
pm.plot_posterior(trace[1000:],
varnames=['difference_of_means', 'difference_of_stds'],
ref_val=0,
alpha=0.3)
# Posterior predictive check
if plot_ppc:
ppc = pm.sample_ppc(trace, samples=500, model=model, size=100)
fig, axes = plt.subplots(nrows=1, ncols=2, figsize=(14,4))
sn.distplot([n.mean() for n in ppc['unregulated']], ax=axes[0])
axes[0].axvline(ureg_data.mean(), c='k')
axes[0].set(title='Posterior predictive of the mean (unregulated)',
xlabel='Mean',
ylabel='Frequency')
sn.distplot([n.mean() for n in ppc['regulated']], ax=axes[1])
axes[1].axvline(reg_data.mean(), c='k')
axes[1].set(title='Posterior predictive of the mean (regulated)',
xlabel='Mean',
ylabel='Frequency')
return trace
# Plot the trajectory of the last 500 sampled values.
plt.plot(theta1_sample[:-500], theta2_sample[:-500], marker='o', color='skyblue')
plt.xlim(0, 1)
plt.ylim(0, 1)
plt.xlabel(r'$\theta1$')
plt.ylabel(r'$\theta2$')
# Display means in plot.
plt.plot(0, label='M = %.3f, %.3f' % (np.mean(theta1_sample), np.mean(theta2_sample)), alpha=0.0)
plt.legend(loc='upper left')
plt.savefig('Figure_8.6.png')
# Plot a histogram of the posterior differences of theta values.
theta_diff = theta1_sample - theta2_sample
pm.plot_posterior(theta_diff, ref_val=0.0, bins=30, color='skyblue')
plt.xlabel(r'$\theta_1 - \theta_2$')
plt.savefig('Figure_8.8.png')
# For Exercise 8.5:
# Posterior prediction. For each step in the chain, use the posterior thetas
# to flip the coins.
chain_len = len(theta1_sample)
# Create matrix to hold results of simulated flips:
y_pred = np.zeros((2, chain_len))
for step_idx in range(chain_len): # step through the chain
# flip the first coin:
p_head1 = theta1_sample[step_idx]
y_pred[0, step_idx] = np.random.choice([0,1], p=[1-p_head1, p_head1])
# flip the second coin:
p_head2 = theta2_sample[step_idx]
plt.subplot(1, 2, 1)
thin_idx = 50
plt.plot(z1[::thin_idx], z0[::thin_idx], 'b.', alpha=0.7)
plt.ylabel('Standardized Intercept')
plt.xlabel('Standardized Slope')
plt.subplot(1, 2, 2)
plt.plot(b1[::thin_idx], b0[::thin_idx], 'b.', alpha=0.7)
plt.ylabel('Intercept (ht when wt=0)')
plt.xlabel('Slope (pounds per inch)')
plt.tight_layout()
plt.savefig('Figure_16.4.png')
# Display the posterior of the b1:
plt.figure(figsize=(8, 5))
ax = plt.subplot(1, 2, 1)
pm.plot_posterior(z1, ref_val=0.0, bins=30, ax=ax)
ax.set_xlabel('Standardized slope')
ax = plt.subplot(1, 2, 2)
pm.plot_posterior(b1, ref_val=0.0, bins=30, ax=ax)
ax.set_xlabel('Slope (pounds per inch)')
plt.tight_layout()
plt.savefig('Figure_16.5.png')
# Display data with believable regression lines and posterior predictions.
plt.figure()
# Plot data values:
x_rang = np.max(x) - np.min(x)
y_rang = np.max(y) - np.min(y)
lim_mult = 0.25
x_lim = [np.min(x)-lim_mult*x_rang, np.max(x)+lim_mult*x_rang]
y_lim = [np.min(y)-lim_mult*y_rang, np.max(y)+lim_mult*y_rang]
scale = np.repeat([sigma[chain_idx]], [len(x_post_pred)]))
for x_idx in range(len(x_post_pred)):
y_HDI_lim[x_idx] = hpd(y_post_pred[x_idx])
# Display believable beta0 and b1 values
plt.figure()
thin_idx = 5
plt.plot(b1[::thin_idx], b0[::thin_idx], '.')
plt.ylabel("Intercept")
plt.xlabel("Slope")
plt.savefig('Figure_16.x0.png')
# Display the posterior of the b1:
ax = pm.plot_posterior(b1, ref_val=0.0, bins=30)
ax.set_xlabel(r'Slope ($\Delta$ tar / $\Delta$ weight)')
plt.title('Mean tdf = %.2f' % tdf_m)
plt.savefig('Figure_16.8b.png')
# Display data with believable regression lines and posterior predictions.
plt.figure()
plt.plot(x, y, 'k.')
plt.title('Data with credible regression lines')
plt.xlabel('weight')
plt.ylabel('tar')
plt.xlim(x_lim)
plt.ylim(y_lim)
# Superimpose a smattering of believable regression lines:
for i in range(0, len(b0), 5):
plt.plot(x, b0[i] + b1[i]*x , c='k', alpha=0.05 )
#pm.summary(trace)
## Check for mixing and autocorrelation
#pm.autocorrplot(trace, vars =[mu, tau])
## Plot KDE and sampled values for each parameter.
#pm.traceplot(trace)
mu_sample = trace['mu']
sigma_sample = trace['sd']
plt.figure(figsize=(10, 6))
ax = plt.subplot(1, 2, 1)
pm.plot_posterior(mu_sample, bins=30, ax=ax)
ax.set_xlabel('mu')
ax.set_title = 'Posterior'
ax.set_xlim(98, 102)
plt.subplot(1, 2, 2)
mu_mean = np.mean(mu_sample)
sigma_mean = np.mean(sigma_sample)
plt.scatter(mu_sample, sigma_sample , c='gray')
plt.plot(mu_mean, sigma_mean, 'C1*',
label=r'$\mu$ = %.1f, $\sigma$ = %.1f' % (mu_mean, sigma_mean))
plt.xlabel('mu')
plt.ylabel('sigma')
plt.title('Posterior')
n_accepted += 1
else:
# reject the proposed jump, stay at current position
trajectory[t+1] = current_position
# increment the rejected counter, just to monitor performance
if t > burn_in:
n_rejected += 1
# Extract the post-burn_in portion of the trajectory.
accepted_traj = trajectory[burn_in:]
# End of Metropolis algorithm.
# Display the posterior.
ROPE = np.array([0.76, 0.8])
pm.plot_posterior(accepted_traj, ref_val=0.9, rope=ROPE)
plt.xlabel = 'theta'
# Display rejected/accepted ratio in the plot.
mean_traj = np.mean(accepted_traj)
std_traj = np.std(accepted_traj)
plt.plot(0, label=r'$N_{pro}=%s$ $\frac{N_{acc}}{N_{pro}} = %.3f$' % (len(accepted_traj), (n_accepted/len(accepted_traj))), alpha=0)
# Evidence for model, p(D).
# Compute a,b parameters for beta distribution that has the same mean
# and stdev as the sample from the posterior. This is a useful choice
# when the likelihood function is Bernoulli.
a = mean_traj * ((mean_traj*(1 - mean_traj)/std_traj**2) - 1)
b = (1 - mean_traj) * ((mean_traj*(1 - mean_traj)/std_traj**2) - 1)
if n_predictors >= 6: # don't display if too many predictors
n_predictors == 6
columns = ['Sigma y', 'Intercept']
[columns.append('Slope_%s' % i) for i in predictor_names[:n_predictors]]
traces = np.array([sigma_samp, b0_samp, b_samp[:,0], b_samp[:,1]]).T
df = pd.DataFrame(traces, columns=columns)
g = sns.PairGrid(df)
g.map(plt.scatter)
plt.savefig('Figure_17.Xa.png')
## Display the posterior:
plt.figure(figsize=(16,4))
ax = plt.subplot(1, n_predictors+2, 1)
pm.plot_posterior(sigma_samp, ax=ax)
ax.set_xlabel(r'$\sigma y$')
ax = plt.subplot(1, n_predictors+2, 2)
pm.plot_posterior(b0_samp, ax=ax)
ax.set_xlabel('Intercept')
for i in range(0, n_predictors):
ax = plt.subplot(1, n_predictors+2, 3+i)
pm.plot_posterior(b_samp[:,i], ref_val=0, ax=ax)
ax.set_xlabel('Slope_%s' % predictor_names[i])
plt.tight_layout()
plt.savefig('Figure_17.Xb.png')
# Posterior prediction:
# Define matrix for recording posterior predicted y values for each xPostPred.
# One row per xPostPred value, with each row holding random predicted y values.
## Plot KDE and sampled values for each parameter.
#pm.traceplot(trace)
pm.traceplot(trace)
# Create arrays with the posterior sample
mu1_sample = trace['mu'][:,0]
mu2_sample = trace['mu'][:,1]
mu3_sample = trace['mu'][:,2]
mu4_sample = trace['mu'][:,3]
# Plot differences among filtrations experiments
fig, ax = plt.subplots(1, 3, figsize=(15, 6))
pm.plot_posterior(mu1_sample-mu2_sample, ax=ax[0], color='skyblue')
ax[0].set_xlabel(r'$\mu1-\mu2$')
# Plot differences among condensation experiments
pm.plot_posterior(mu3_sample-mu4_sample, ax=ax[1], color='skyblue')
ax[1].set_xlabel(r'$\mu3-\mu4$')
# Plot differences between filtration and condensation experiments
a = (mu1_sample+mu2_sample)/2 - (mu3_sample+mu4_sample)/2
pm.plot_posterior(a, ax=ax[2], color='skyblue')
ax[2].set_xlabel(r'$(\mu1+\mu2)/2 - (\mu3+\mu4)/2$')
plt.tight_layout()
plt.savefig('Figure_9.16.png')
plt.show()
def posterior_plot(self, **kwargs):
return pm.plot_posterior(self.posterior_, **kwargs)
# define priors
prior_v1 = pm.Beta('prior_v1', alpha=2, beta=2)
prior_v2 = pm.Beta('prior_v2', alpha=2, beta=2)
# define likelihood
like_v1 = pm.Binomial('like_v1', n=n, p=prior_v1, observed=obs_v1)
like_v2 = pm.Binomial('like_v2', n=n, p=prior_v2, observed=obs_v2)
# define metrics
pm.Deterministic('difference', prior_v2 - prior_v1)
pm.Deterministic('relation', (prior_v2/prior_v1) - 1)
# inference
trace = pm.sample(draws=50000, step=pm.Metropolis(), start=pm.find_MAP(), progressbar=True)
_ = pm.plot_posterior(trace[1000:], varnames=['difference', 'relation'],
ref_val=0, color='#87ceeb')
# NOTE
# n - Number of training examples.
# i - ith training example in a data set.
# y(i) - Ground truth label for ith training example.
# y_hat(i) - Prediction for ith training example.
## Compute MSE
import numpy as np
y_hat = np.array([0.000, 0.166, 0.333])
y_true = np.array([0.000, 0.254, 0.998])
def rmse(predictions, targets):
differences = predictions - targets
differences_squared = differences ** 2
mean_of_differences_squared = differences_squared.mean()
y = pm.Bernoulli('y', p=theta, observed=y)
# Generate a MCMC chain
trace = pm.sample(1000)
# create an array with the posterior sample
theta_sample = trace['theta']
fig, ax = plt.subplots(1, 2)
ax[0].plot(theta_sample[:500], np.arange(500), marker='o', color='skyblue')
ax[0].set_xlim(0, 1)
ax[0].set_xlabel(r'$\theta$')
ax[0].set_ylabel('Position in Chain')
pm.plot_posterior(theta_sample, ax=ax[1], color='skyblue');
ax[1].set_xlabel(r'$\theta$');
# Posterior prediction:
# For each step in the chain, use posterior theta to flip a coin:
y_pred = np.zeros(len(theta_sample))
for i, p_head in enumerate(theta_sample):
y_pred[i] = np.random.choice([0, 1], p=[1 - p_head, p_head])
# Jitter the 0,1 y values for plotting purposes:
y_pred_jittered = y_pred + np.random.uniform(-.05, .05, size=len(theta_sample))
# Now plot the jittered values:
plt.figure()
plt.plot(theta_sample[:500], y_pred_jittered[:500], 'C1o')
plt.xlim(-.1, 1.1)
# likehood
y = pm.Normal('y', mu=means[idx], sd=sds[idx], observed=y)
trace = pm.sample(5000, njobs=1)
chain = trace[100::]
fig = plt.figure()
pm.traceplot(chain)
pdf_all.savefig()
# mean, standard deviation, and the HPD intervals
print(pm.summary(trace))
#
dist = stats.norm()
fig, ax = plt.subplots(3, 2, figsize=(16,12))
comparisons = [(i,j) for i in range(len(set(idx))) for j in range(i+1, len(set(idx)))]
pos = [(k,l) for k in range(3) for l in (0,1)]
for (i,j), (k,l) in zip(comparisons, pos):
means_diff = chain['means'][:,i] - chain['means'][:,j]
d_cohen = (means_diff / np.sqrt((chain['sds'][:,i]**2 + chain['sds'][:,j]**2)/2) ).mean()
ps = dist.cdf(d_cohen/(2**0.5))
pm.plot_posterior(means_diff, ref_val=0, ax=ax[k,l], color='skyblue')
ax[k,l].plot(0, label="Cohen's d={:.2f}\nPrbo sup={:.2f}".format(d_cohen, ps), alpha=0)
ax[k,l].set_xlabel('$\mu_{}-\mu_{}$'.format(i, j), fontsize=15)
ax[k,l ].legend(loc=0, fontsize=14)
pdf_all.savefig(fig)
# Extract values of 'a'
a0_sample = trace['a0']
b1_sample = trace['b1']
b2_sample = trace['b2']
b1b2_sample = trace['b1b2']
b0_sample = a0_sample * np.std(y) + np.mean(y)
b1_sample = b1_sample * np.std(y)
b2_sample = b2_sample * np.std(y)
b1b2_sample = b1b2_sample * np.std(y)
plt.figure(figsize=(25,20))
ax = plt.subplot(451)
pm.plot_posterior(b0_sample, bins=50, ax=ax)
ax.set_xlabel(r'$\beta0$')
ax.set_title('Baseline')
plt.xlim(b0_sample.min(), b0_sample.max());
count = 2
for i in range(len(b1_sample[0])):
ax = plt.subplot(4, 5, count)
pm.plot_posterior(b1_sample[:,i], ax=ax)
ax.set_xlabel(r'$\beta1_{}$'.format(i))
ax.set_title('x1: {}'.format(x1names[i]))
count += 1
for i in range(len(b2_sample[0])):
ax = plt.subplot(4, 5, count)
pm.plot_posterior(b2_sample[:,i], bins=50, ax=ax)
#pm.autocorrplot(trace, varnames=['mu', 'kappa'])
## Plot KDE and sampled values for each parameter.
#pm.traceplot(trace[burnin:])
pm.traceplot(trace)
# Create arrays with the posterior sample
mu1_sample = trace['mu'][:,0][burnin:]
mu2_sample = trace['mu'][:,1][burnin:]
mu3_sample = trace['mu'][:,2][burnin:]
mu4_sample = trace['mu'][:,3][burnin:]
# Plot differences among filtrations experiments
fig, ax = plt.subplots(1, 3, figsize=(15, 6))
pm.plot_posterior((mu1_sample-mu2_sample), ax=ax[0], ref_val=0, color='skyblue')
ax[0].set_xlabel(r'$\mu1-\mu2$')
# Plot differences among condensation experiments
pm.plot_posterior((mu3_sample-mu4_sample), ax=ax[1], ref_val=0, color='skyblue')
ax[1].set_xlabel(r'$\mu3-\mu4$')
# Plot differences between filtration and condensation experiments
a = (mu1_sample+mu2_sample)/2 - (mu3_sample+mu4_sample)/2
pm.plot_posterior(a, ax=ax[2], ref_val=0, color='skyblue')
ax[2].set_xlabel(r'$(\mu1+\mu2)/2 - (\mu3+\mu4)/2$')
plt.tight_layout()
plt.savefig('Figure_9.18_upper.png')
plt.show()
#pm.autocorrplot(trace, vars =[nu, eta])
## Plot KDE and sampled values for each parameter.
#pm.traceplot(trace)
model_idx_sample = trace['model_index']
pM1 = sum(model_idx_sample == 0) / len(model_idx_sample)
pM2 = 1 - pM1
nu_sample_M1 = trace['nu'][model_idx_sample == 0]
eta_sample_M2 = trace['eta'][model_idx_sample == 1]
plt.figure()
plt.subplot(2, 1, 1)
pm.plot_posterior(nu_sample_M1)
plt.xlabel(r'$\nu$')
plt.ylabel('frequency')
plt.title(r'p($\nu$|D,M2), with p(M2|D)={:.3}f'.format(pM1), fontsize=14)
plt.xlim(-8, 8)
plt.subplot(2, 1, 2)
pm.plot_posterior(eta_sample_M2)
plt.xlabel(r'$\eta$')
plt.ylabel('frequency')
plt.title(r'p($\eta$|D,M2), with p(M2|D)={:.3f}'.format(pM2), fontsize=14)
plt.xlim(0, 8)
plt.savefig('figure_ex_10.2_a.png')
plt.show()
def robust_lin_reg(df, var_map,
steps=2000, mcmc='metropolis',
plot_trace=True, plot_vars=True):
""" Robust Bayesian linear regression.
Args:
df Dataframe. Must have a column containing values
and a categorical 'regulated' column that is [0, 1]
to define the two groups
val_map Dict specifying x and y vars: {'x':'expl_var',
'y':'resp_var'}
steps Number of steps to take in MCMC chains
mcmc Sampler to use: ['metropolis', 'slice', 'nuts']
plot_trace Whether to plot the MCMC traces
plot_vars Whether to plot posteriors for variables
Returns:
Creates plots showing the distribution of differences in
means and variances, plus optional diagnostics. Returns the
MCMC trace
"""
import pymc3 as pm
import pandas as pd
import matplotlib.pyplot as plt
import numpy as np
import theano
# Get cols
df = df[var_map.values()]
# Swap keys and values
var_map_rev = dict((v,k) for k,v in var_map.iteritems())
# Convert df columns to x and y
df.columns = [var_map_rev[i] for i in df.columns]
with pm.Model() as model:
# Priors
nu = pm.Exponential('v_minus_one', 1./29.) + 1
# The patsy string below automatically assumes mu=0 and estimates
# lam = (1/s.d.**2), so don't need to add these. Do need to add
# prior for nu though.
family = pm.glm.families.StudentT(nu=nu)
# Define model
pm.glm.glm('y ~ x', df, family=family)
# Find MAP as starting point
start = pm.find_MAP()
# Run sampler to approximate posterior
if mcmc == 'metropolis':
step = pm.Metropolis()
trace = pm.sample(steps, step, start=start)
elif mcmc == 'slice':
step = pm.Slice()
trace = pm.sample(steps, step, start=start)
elif mcmc == 'nuts':
step = pm.NUTS(scaling=start)
trace = pm.sample(steps, step)
else:
raise ValueError("mcmc must be one of ['metropolis', 'slice', 'nuts']")
# Traces
if plot_trace:
pm.traceplot(trace)
# Posteriors for variables
if plot_vars:
pm.plot_posterior(trace[-1000:],
varnames=['v_minus_one', 'lam'],
alpha=0.3)
pm.plot_posterior(trace[1000:],
varnames=['x', 'Intercept'],
ref_val=0,
alpha=0.3)
# PPC
fig = plt.figure(figsize=(10, 10))
ax = fig.add_subplot(111, xlabel=var_map['x'], ylabel=var_map['y'])
ax.scatter(df.x, df.y, marker='o', label='Data')
pm.glm.plot_posterior_predictive(trace, samples=50, eval=df.x,
label='PPC', alpha=0.3)
return trace
pm.autocorrplot(trace[burnin:], varnames=['mu', 'kappa']) #pm.autocorrplot(trace, vars =[mu, kappa]) ## Plot KDE and sampled values for each parameter. pm.traceplot(trace[burnin:]) #pm.traceplot(trace) # Create arrays with the posterior sample theta1_sample = trace['theta'][:,0][burnin:] theta28_sample = trace['theta'][:,27][burnin:] mu_sample = trace['mu'][burnin:] kappa_sample = trace['kappa'][burnin:] # Plot mu histogram fig, ax = plt.subplots(2, 2, figsize=(12,12)) pm.plot_posterior(mu_sample, ax=ax[0, 0], color='skyblue') ax[0, 0].set_xlabel(r'$\mu$') # Plot kappa histogram pm.plot_posterior(kappa_sample, ax=ax[0, 1], color='skyblue') ax[0, 1].set_xlabel(r'$\kappa$') # Plot theta 1 pm.plot_posterior(theta1_sample, ax=ax[1, 0], color='skyblue') ax[1, 0].set_xlabel(r'$\theta1$') # Plot theta 28 pm.plot_posterior(theta1_sample, ax=ax[1, 1], color='skyblue') ax[1, 1].set_xlabel(r'$\theta28$')
theta2_sample = trace['theta'][:, 1] theta3_sample = trace['theta'][:, 2] mu_sample = trace['mu'] kappa_sample = trace['kappa'] # Scatter plot hyper-parameters fig, ax = plt.subplots(4, 3, figsize=(12, 12)) ax[0, 0].scatter(mu_sample, kappa_sample, marker='o', color='skyblue') ax[0, 0].set_xlim(0, 1) ax[0, 0].set_xlabel(r'$\mu$') ax[0, 0].set_ylabel(r'$\kappa$') # Plot mu histogram #plot_post(mu_sample, xlab=r'$\mu$', show_mode=False, labelsize=9, framealpha=0.5) pm.plot_posterior(mu_sample, ax=ax[0, 1], color='skyblue') ax[0, 1].set_xlabel(r'$\mu$') ax[0, 1].set_xlim(0, 1) # Plot kappa histogram #plot_post(kappa_sample, xlab=r'$\kappa$', show_mode=False, labelsize=9, framealpha=0.5) pm.plot_posterior(kappa_sample, ax=ax[0, 2], color='skyblue') ax[0, 2].set_xlabel(r'$\kappa$') # Plot theta 1 #plot_post(theta1_sample, xlab=r'$\theta1$', show_mode=False, labelsize=9, framealpha=0.5) pm.plot_posterior(theta1_sample, ax=ax[1, 0], color='skyblue') ax[1, 0].set_xlabel(r'$\theta1$') ax[1, 0].set_xlim(0, 1)
#pm.autocorrplot(trace, vars=model.unobserved_RVs[:-1])
## Plot KDE and sampled values for each parameter.
pm.traceplot(trace)
a0_sample = trace['a0']
b_sample = trace['b']
b0_sample = a0_sample * np.std(y) + np.mean(y)
b_sample = b_sample * np.std(y)
plt.figure(figsize=(20, 4))
for i in range(5):
ax = plt.subplot(1, 5, i+1)
pm.plot_posterior(b_sample[:,i], bins=50, ax=ax)
ax.set_xlabel=r'$\beta1_{}$'.format(i)
ax.set_title='x:{}'.format(i)
plt.tight_layout()
plt.savefig('Figure_18.xa.png')
nContrasts = len(contrast_dict)
if nContrasts > 0:
plt.figure(figsize=(20, 8))
count = 1
for key, value in contrast_dict.items():
contrast = np.dot(b_sample, value)
ax = plt.subplot(2, 4, count)
pm.plot_posterior(contrast, ref_val=0.0, bins=50, ax=ax)
ax.set_title('Contrast {}'.format(key))
group1_mean - group2_mean)
diff_of_stds = pm.Deterministic('difference of stds',
group1_std - group2_std)
effect_size = pm.Deterministic(
'effect size', diff_of_means / np.sqrt(
(group1_std**2 + group2_std**2) / 2))
# RUN
#trace = pm.sample(2000, cores=2) # Nota Bene: https://github.com/pymc-devs/pymc3/issues/3388
trace = pm.sample(1000, tune=1000, cores=1)
pm.kdeplot(np.random.exponential(30, size=10000), shade=0.5)
pm.plot_posterior(trace,
varnames=[
'group1_mean', 'group2_mean', 'group1_std', 'group2_std',
'ν_minus_one'
],
color='#87ceeb')
pm.plot_posterior(
trace,
varnames=['difference of means', 'difference of stds', 'effect size'],
ref_val=0,
color='#87ceeb')
pm.forestplot(trace, varnames=['group1_mean', 'group2_mean'])
pm.forestplot(trace, varnames=['group1_std', 'group2_std', 'ν_minus_one'])
pm.summary(
trace,
## Print summary for each trace
#pm.summary(trace)
## Check for mixing and autocorrelation
#pm.autocorrplot(trace, vars =[mu, tau])
## Plot KDE and sampled values for each parameter.
#pm.traceplot(trace)
## Extract chains
muG_sample = trace['muG']
tauG_sample = trace['tauG']
m_sample = trace['m']
d_sample = trace['d']
# Plot the hyperdistributions:
_, ax = plt.subplots(1, 4, figsize=(20, 5))
pm.plot_posterior(muG_sample, bins=30, ax=ax[0])
ax[0].set_xlabel(r'$\mu_g$', fontsize=16)
pm.plot_posterior(tauG_sample, bins=30 ,ax=ax[1])
ax[1].set_xlabel(r'$\tau_g$', fontsize=16)
pm.plot_posterior(m_sample, bins=30, ax=ax[2])
ax[2].set_xlabel('m', fontsize=16)
pm.plot_posterior(d_sample, bins=30, ax=ax[3])
ax[3].set_xlabel('d', fontsize=16)
plt.tight_layout()
plt.savefig('Figure_15.9.png')
plt.show()
