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untabified priors.py
This commit is contained in:
Nicolò Fusi
parent
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commit
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1 changed files with 103 additions and 103 deletions
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@ -8,120 +8,120 @@ from scipy.special import gammaln, digamma
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from ..util.linalg import pdinv
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from ..util.linalg import pdinv
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class prior:
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class prior:
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def pdf(self,x):
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def pdf(self,x):
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return np.exp(self.lnpdf(x))
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return np.exp(self.lnpdf(x))
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def plot(self):
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def plot(self):
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rvs = self.rvs(1000)
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rvs = self.rvs(1000)
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pb.hist(rvs,100,normed=True)
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pb.hist(rvs,100,normed=True)
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xmin,xmax = pb.xlim()
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xmin,xmax = pb.xlim()
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xx = np.linspace(xmin,xmax,1000)
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xx = np.linspace(xmin,xmax,1000)
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pb.plot(xx,self.pdf(xx),'r',linewidth=2)
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pb.plot(xx,self.pdf(xx),'r',linewidth=2)
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class Gaussian(prior):
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class Gaussian(prior):
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"""
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"""
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Implementation of the univariate Gaussian probability function, coupled with random variables, since scipy.stats sucks.
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Implementation of the univariate Gaussian probability function, coupled with random variables, since scipy.stats sucks.
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Using Bishop 2006 notation"""
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Using Bishop 2006 notation"""
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def __init__(self,mu,sigma):
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def __init__(self,mu,sigma):
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self.mu = float(mu)
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self.mu = float(mu)
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self.sigma = float(sigma)
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self.sigma = float(sigma)
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self.sigma2 = np.square(self.sigma)
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self.sigma2 = np.square(self.sigma)
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self.constant = -0.5*np.log(2*np.pi*self.sigma2)
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self.constant = -0.5*np.log(2*np.pi*self.sigma2)
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def __str__(self):
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def __str__(self):
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return "N("+str(np.round(self.mu))+', '+str(np.round(self.sigma2))+')'
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return "N("+str(np.round(self.mu))+', '+str(np.round(self.sigma2))+')'
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def lnpdf(self,x):
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def lnpdf(self,x):
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return self.constant - 0.5*np.square(x-self.mu)/self.sigma2
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return self.constant - 0.5*np.square(x-self.mu)/self.sigma2
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def lnpdf_grad(self,x):
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def lnpdf_grad(self,x):
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return -(x-self.mu)/self.sigma2
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return -(x-self.mu)/self.sigma2
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def rvs(self,n):
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def rvs(self,n):
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return np.random.randn(n)*self.sigma + self.mu
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return np.random.randn(n)*self.sigma + self.mu
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class log_Gaussian(prior):
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class log_Gaussian(prior):
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"""
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"""
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"""
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"""
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def __init__(self,mu,sigma):
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def __init__(self,mu,sigma):
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self.mu = float(mu)
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self.mu = float(mu)
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self.sigma = float(sigma)
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self.sigma = float(sigma)
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self.sigma2 = np.square(self.sigma)
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self.sigma2 = np.square(self.sigma)
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self.constant = -0.5*np.log(2*np.pi*self.sigma2)
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self.constant = -0.5*np.log(2*np.pi*self.sigma2)
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def __str__(self):
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def __str__(self):
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return "lnN("+str(np.round(self.mu))+', '+str(np.round(self.sigma2))+')'
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return "lnN("+str(np.round(self.mu))+', '+str(np.round(self.sigma2))+')'
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def lnpdf(self,x):
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def lnpdf(self,x):
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return self.constant - 0.5*np.square(np.log(x)-self.mu)/self.sigma2 -np.log(x)
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return self.constant - 0.5*np.square(np.log(x)-self.mu)/self.sigma2 -np.log(x)
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def lnpdf_grad(self,x):
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def lnpdf_grad(self,x):
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return -((np.log(x)-self.mu)/self.sigma2+1.)/x
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return -((np.log(x)-self.mu)/self.sigma2+1.)/x
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def rvs(self,n):
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def rvs(self,n):
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return np.exp(np.random.randn(n)*self.sigma + self.mu)
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return np.exp(np.random.randn(n)*self.sigma + self.mu)
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class multivariate_Gaussian:
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class multivariate_Gaussian:
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"""
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"""
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Implementation of the multivariate Gaussian probability function, coupled with random variables, since scipy.stats sucks.
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Implementation of the multivariate Gaussian probability function, coupled with random variables, since scipy.stats sucks.
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Using Bishop 2006 notation"""
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Using Bishop 2006 notation"""
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def __init__(self,mu,var):
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def __init__(self,mu,var):
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self.mu = np.array(mu).flatten()
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self.mu = np.array(mu).flatten()
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self.var = np.array(var)
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self.var = np.array(var)
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assert len(self.var.shape)==2
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assert len(self.var.shape)==2
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assert self.var.shape[0]==self.var.shape[1]
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assert self.var.shape[0]==self.var.shape[1]
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assert self.var.shape[0]==self.mu.size
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assert self.var.shape[0]==self.mu.size
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self.D = self.mu.size
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self.D = self.mu.size
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self.inv, self.hld = pdinv(self.var)
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self.inv, self.hld = pdinv(self.var)
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self.constant = -0.5*self.D*np.log(2*np.pi) - self.hld
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self.constant = -0.5*self.D*np.log(2*np.pi) - self.hld
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def summary(self):
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def summary(self):
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pass #TODO
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pass #TODO
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def pdf(self,x):
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def pdf(self,x):
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return np.exp(self.lnpdf(x))
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return np.exp(self.lnpdf(x))
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def lnpdf(self,x):
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def lnpdf(self,x):
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d = x-self.mu
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d = x-self.mu
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return self.constant - 0.5*np.sum(d*np.dot(d,self.inv),1)
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return self.constant - 0.5*np.sum(d*np.dot(d,self.inv),1)
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def lnpdf_grad(self,x):
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def lnpdf_grad(self,x):
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d = x-self.mu
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d = x-self.mu
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return -np.dot(self.inv,d)
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return -np.dot(self.inv,d)
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def rvs(self,n):
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def rvs(self,n):
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return np.random.multivariate_normal(self.mu, self.var,n)
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return np.random.multivariate_normal(self.mu, self.var,n)
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def plot(self):
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def plot(self):
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if self.D==2:
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if self.D==2:
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rvs = self.rvs(200)
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rvs = self.rvs(200)
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pb.plot(rvs[:,0],rvs[:,1], 'kx', mew=1.5)
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pb.plot(rvs[:,0],rvs[:,1], 'kx', mew=1.5)
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xmin,xmax = pb.xlim()
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xmin,xmax = pb.xlim()
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ymin,ymax = pb.ylim()
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ymin,ymax = pb.ylim()
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xx, yy = np.mgrid[xmin:xmax:100j, ymin:ymax:100j]
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xx, yy = np.mgrid[xmin:xmax:100j, ymin:ymax:100j]
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xflat = np.vstack((xx.flatten(),yy.flatten())).T
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xflat = np.vstack((xx.flatten(),yy.flatten())).T
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zz = self.pdf(xflat).reshape(100,100)
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zz = self.pdf(xflat).reshape(100,100)
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pb.contour(xx,yy,zz,linewidths=2)
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pb.contour(xx,yy,zz,linewidths=2)
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def gamma_from_EV(E,V):
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def gamma_from_EV(E,V):
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"""create an instance of a gamma prior by specifying the Expected value(s) and Variance(s) of the distribution"""
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"""create an instance of a gamma prior by specifying the Expected value(s) and Variance(s) of the distribution"""
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a = np.square(E)/V
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a = np.square(E)/V
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b = E/V
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b = E/V
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return gamma(a,b)
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return gamma(a,b)
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class gamma(prior):
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class gamma(prior):
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"""
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"""
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Implementation of the Gamma probability function, coupled with random variables, since scipy.stats sucks.
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Implementation of the Gamma probability function, coupled with random variables, since scipy.stats sucks.
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Using Bishop 2006 notation
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Using Bishop 2006 notation
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"""
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"""
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def __init__(self,a,b):
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def __init__(self,a,b):
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self.a = float(a)
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self.a = float(a)
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self.b = float(b)
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self.b = float(b)
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self.constant = -gammaln(self.a) + a*np.log(b)
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self.constant = -gammaln(self.a) + a*np.log(b)
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def __str__(self):
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def __str__(self):
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return "Ga("+str(np.round(self.a))+', '+str(np.round(self.b))+')'
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return "Ga("+str(np.round(self.a))+', '+str(np.round(self.b))+')'
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def summary(self):
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def summary(self):
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ret = {"E[x]": self.a/self.b,\
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ret = {"E[x]": self.a/self.b,\
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"E[ln x]": digamma(self.a) - np.log(self.b),\
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"E[ln x]": digamma(self.a) - np.log(self.b),\
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"var[x]": self.a/self.b/self.b,\
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"var[x]": self.a/self.b/self.b,\
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"Entropy": gammaln(self.a) - (self.a-1.)*digamma(self.a) - np.log(self.b) + self.a}
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"Entropy": gammaln(self.a) - (self.a-1.)*digamma(self.a) - np.log(self.b) + self.a}
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if self.a >1:
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if self.a >1:
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ret['Mode'] = (self.a-1.)/self.b
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ret['Mode'] = (self.a-1.)/self.b
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else:
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else:
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ret['mode'] = np.nan
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ret['mode'] = np.nan
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return ret
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return ret
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def lnpdf(self,x):
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def lnpdf(self,x):
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return self.constant + (self.a-1)*np.log(x) - self.b*x
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return self.constant + (self.a-1)*np.log(x) - self.b*x
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def lnpdf_grad(self,x):
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def lnpdf_grad(self,x):
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return (self.a-1.)/x - self.b
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return (self.a-1.)/x - self.b
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def rvs(self,n):
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def rvs(self,n):
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return np.random.gamma(scale=1./self.b,shape=self.a,size=n)
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return np.random.gamma(scale=1./self.b,shape=self.a,size=n)
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