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added dKdiag_dtheta for the periodic kernels

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Nicolas 2013-03-01 16:52:37 +00:00
parent 4674ed4558
commit adfe587c86
3 changed files with 195 additions and 3 deletions
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64
GPy/kern/periodic_exponential.py
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@ -162,9 +162,67 @@ class periodic_exponential(kernpart):
dK_dper = mdot(dFX_dper,self.Gi,FX2.T) - mdot(FX,self.Gi,dG_dper,self.Gi,FX2.T) + mdot(FX,self.Gi,dFX2_dper.T)
# np.add(target[:,:,0],dK_dvar, target[:,:,0])
target[0] += np.sum(dK_dvar*partial)
#np.add(target[:,:,1],dK_dlen, target[:,:,1])
target[1] += np.sum(dK_dlen*partial)
#np.add(target[:,:,2],dK_dper, target[:,:,2])
target[2] += np.sum(dK_dper*partial)
def dKdiag_dtheta(self,partial,X,target):
"""derivative of the diagonal of the covariance matrix with respect to the parameters"""
FX = self._cos(self.basis_alpha[None,:],self.basis_omega[None,:],self.basis_phi[None,:])(X)
La = np.column_stack((self.a[0]*np.ones((self.n_basis,1)),self.a[1]*self.basis_omega))
Lo = np.column_stack((self.basis_omega,self.basis_omega))
Lp = np.column_stack((self.basis_phi,self.basis_phi+np.pi/2))
r,omega,phi = self._cos_factorization(La,Lo,Lp)
Gint = self._int_computation( r,omega,phi, r,omega,phi)
Flower = np.array(self._cos(self.basis_alpha,self.basis_omega,self.basis_phi)(self.lower))[:,None]
#dK_dvar
dK_dvar = 1./self.variance*mdot(FX,self.Gi,FX.T)
#dK_dlen
da_dlen = [-1./self.lengthscale**2,0.]
dLa_dlen = np.column_stack((da_dlen[0]*np.ones((self.n_basis,1)),da_dlen[1]*self.basis_omega))
r1,omega1,phi1 = self._cos_factorization(dLa_dlen,Lo,Lp)
dGint_dlen = self._int_computation(r1,omega1,phi1, r,omega,phi)
dGint_dlen = dGint_dlen + dGint_dlen.T
dG_dlen = 1./2*Gint + self.lengthscale/2*dGint_dlen
dK_dlen = -mdot(FX,self.Gi,dG_dlen/self.variance,self.Gi,FX.T)
#dK_dper
dFX_dper = self._cos(-self.basis_alpha[None,:]*self.basis_omega[None,:]/self.period*X ,self.basis_omega[None,:],self.basis_phi[None,:]+np.pi/2)(X)
dLa_dper = np.column_stack((-self.a[0]*self.basis_omega/self.period, -self.a[1]*self.basis_omega**2/self.period))
dLp_dper = np.column_stack((self.basis_phi+np.pi/2,self.basis_phi+np.pi))
r1,omega1,phi1 = self._cos_factorization(dLa_dper,Lo,dLp_dper)
IPPprim1 = self.upper*(1./(omega+omega1.T)*np.cos((omega+omega1.T)*self.upper+phi+phi1.T-np.pi/2) + 1./(omega-omega1.T)*np.cos((omega-omega1.T)*self.upper+phi-phi1.T-np.pi/2))
IPPprim1 -= self.lower*(1./(omega+omega1.T)*np.cos((omega+omega1.T)*self.lower+phi+phi1.T-np.pi/2) + 1./(omega-omega1.T)*np.cos((omega-omega1.T)*self.lower+phi-phi1.T-np.pi/2))
IPPprim2 = self.upper*(1./(omega+omega1.T)*np.cos((omega+omega1.T)*self.upper+phi+phi1.T-np.pi/2) + self.upper*np.cos(phi-phi1.T))
IPPprim2 -= self.lower*(1./(omega+omega1.T)*np.cos((omega+omega1.T)*self.lower+phi+phi1.T-np.pi/2) + self.lower*np.cos(phi-phi1.T))
IPPprim = np.where(np.isnan(IPPprim1),IPPprim2,IPPprim1)
IPPint1 = 1./(omega+omega1.T)**2*np.cos((omega+omega1.T)*self.upper+phi+phi1.T-np.pi) + 1./(omega-omega1.T)**2*np.cos((omega-omega1.T)*self.upper+phi-phi1.T-np.pi)
IPPint1 -= 1./(omega+omega1.T)**2*np.cos((omega+omega1.T)*self.lower+phi+phi1.T-np.pi) + 1./(omega-omega1.T)**2*np.cos((omega-omega1.T)*self.lower+phi-phi1.T-np.pi)
IPPint2 = 1./(omega+omega1.T)**2*np.cos((omega+omega1.T)*self.upper+phi+phi1.T-np.pi) + 1./2*self.upper**2*np.cos(phi-phi1.T)
IPPint2 -= 1./(omega+omega1.T)**2*np.cos((omega+omega1.T)*self.lower+phi+phi1.T-np.pi) + 1./2*self.lower**2*np.cos(phi-phi1.T)
IPPint = np.where(np.isnan(IPPint1),IPPint2,IPPint1)
dLa_dper2 = np.column_stack((-self.a[1]*self.basis_omega/self.period))
dLp_dper2 = np.column_stack((self.basis_phi+np.pi/2))
r2,omega2,phi2 = dLa_dper2.T,Lo[:,0:1],dLp_dper2.T
dGint_dper = np.dot(r,r1.T)/2 * (IPPprim - IPPint) + self._int_computation(r2,omega2,phi2, r,omega,phi)
dGint_dper = dGint_dper + dGint_dper.T
dFlower_dper = np.array(self._cos(-self.lower*self.basis_alpha*self.basis_omega/self.period,self.basis_omega,self.basis_phi+np.pi/2)(self.lower))[:,None]
dG_dper = 1./self.variance*(self.lengthscale/2*dGint_dper + self.b[0]*(np.dot(dFlower_dper,Flower.T)+np.dot(Flower,dFlower_dper.T)))
dK_dper = 2*mdot(dFX_dper,self.Gi,FX.T) - mdot(FX,self.Gi,dG_dper,self.Gi,FX.T)
target[0] += np.sum(np.diag(dK_dvar)*partial)
target[1] += np.sum(np.diag(dK_dlen)*partial)
target[2] += np.sum(np.diag(dK_dper)*partial)