def UQTkEvaluatePCE(pc_model, pc_coeffs, samples):
"""
Evaluate PCE at a set of samples of this PCE
Input:
pc_model: PC object with into about PCE
pc_coeffs: 1D numpy array with PC coefficients of the RV to be evaluated. [npce]
samples: 2D numpy array with samples of the PCE at which the RV
are to be evaluated. Each line is one sample. [n_samples, ndim]
Output:
1D Numpy array with PCE evaluations
"""
#need a 1d array passed into pc_coeffs
if (len(pc_coeffs.shape) != 1):
print(
"UQTkEvaluatePCE only takes one PCE. pc_coeff needs to be 1 dimension."
)
exit(1)
# Get data set dimensions etc.
n_test_samples = samples.shape[0]
ndim = samples.shape[1]
npce = pc_model.GetNumberPCTerms()
# Put PC samples in a UQTk array
std_samples_uqtk = uqtkarray.dblArray2D(n_test_samples, ndim)
std_samples_uqtk.setnpdblArray(np.asfortranarray(samples))
# Create and fill UQTk array for PC coefficients
c_k_1d_uqtk = uqtkarray.dblArray1D(npce, 0.0)
for ip in range(npce):
c_k_1d_uqtk[ip] = pc_coeffs[ip]
# Create UQTk array to store outputs in
rv_from_pce_uqtk = uqtkarray.dblArray1D(n_test_samples, 0.0)
# Evaluate the PCEs for reach input RV at those random samples
pc_model.EvalPCAtCustPoints(rv_from_pce_uqtk, std_samples_uqtk,
c_k_1d_uqtk)
# Numpy array to store all RVs evaluated from sampled PCEs
rvs_sampled = np.zeros((n_test_samples, ))
# Put evaluated samples in full 2D numpy array
for isamp in range(n_test_samples):
rvs_sampled[isamp] = rv_from_pce_uqtk[isamp]
# return numpy array of PCE evaluations
return rvs_sampled
def transf_coeffs_xi(coeffs,
nord,
ndim,
pc_type,
param,
R,
sf="sparse",
pc_alpha=0.0,
pc_beta=1.0):
'''
Transfer coefficient from eta-space to xi-space to check convergence
eta-space is the current dimension-reduced space, while
xi-space is the full dimension expansion space.
Dimension of Eta is equal to dimension of Xi
Inputs:
coeffs: N dimensional numpy array (N is the # of PC terms of ndim dimensional expansion),
coefficients in eta space
Output:
N dimensional numpy array, coefficients projected to xi space
this function is only used to check the accuracy of adaptation method
'''
##### obtain pc_model of eta space and xi space #####
pc_model_eta = uqtkpce.PCSet("NISP", nord, ndim, pc_type, pc_alpha,
pc_beta)
pc_model_xi = uqtkpce.PCSet("NISP", nord, ndim, pc_type, pc_alpha, pc_beta)
if ndim == 1:
pc_model_eta.SetQuadRule(pc_type, 'full', param)
pc_model_xi.SetQuadRule(pc_type, 'full', param)
else:
pc_model_eta.SetQuadRule(pc_type, sf, param)
pc_model_xi.SetQuadRule(pc_type, sf, param)
qdpts_eta, totquat_eta = pce_tools.UQTkGetQuadPoints(pc_model_eta)
##### Obtain Psi_xi at quadrature points of eta #####
qdpts_xi = eta_to_xi_mapping(qdpts_eta, R)
qdpts_xi_uqtk = uqtkarray.dblArray2D(totquat_eta, ndim)
qdpts_xi_uqtk.setnpdblArray(np.asfortranarray(qdpts_xi))
psi_xi_uqtk = uqtkarray.dblArray2D()
pc_model_xi.EvalBasisAtCustPts(qdpts_xi_uqtk, psi_xi_uqtk)
psi_xi = np.zeros((totquat_eta, pc_model_xi.GetNumberPCTerms()))
psi_xi_uqtk.getnpdblArray(psi_xi)
##### Obtian Psi_eta at quadrature points of eta #####
weight_eta_uqtk = uqtkarray.dblArray1D()
pc_model_eta.GetQuadWeights(weight_eta_uqtk)
weight_eta = np.zeros((totquat_eta, ))
weight_eta_uqtk.getnpdblArray(weight_eta)
psi_eta_uqtk = uqtkarray.dblArray2D()
pc_model_eta.GetPsi(psi_eta_uqtk)
psi_eta = np.zeros((totquat_eta, pc_model_eta.GetNumberPCTerms()))
psi_eta_uqtk.getnpdblArray(psi_eta)
return np.dot(coeffs, np.dot(psi_eta.T * weight_eta, psi_xi))
def UQTkDrawSamplesPCE(pc_model, pc_coeffs, n_samples):
"""
Draw samples of the germ underneath the pc_model and evaluates one PCE
for those samples.
Input:
pc_model: PC object with into about PCE
pc_coeffs: 1D numpy array with PC coefficients of the RV to be evaluated. [n_dim]
n_samples: number of samples to be drawn
Output:
1D Numpy array with PCE evaluations
"""
#need a 1d array passed into pc_coeffs
if (len(pc_coeffs.shape) != 1):
print(
"UQTkEvaluatePCE only takes one PCE. pc_coeff needs to be 1 dimension."
)
exit(1)
#get number of nTerms
npce = pc_model.GetNumberPCTerms()
# Create and fill UQTk array for PC coefficients
p = uqtkarray.dblArray1D(npce, 0.0)
for ip in range(npce):
p[ip] = pc_coeffs[ip]
#create UQTk array to store outputs in
samples = uqtkarray.dblArray1D(n_samples, 0.0)
#draw the samples
pc_model.DrawSampleSet(p, samples)
#convert samples to a numpy array
pce_samples = np.zeros(n_samples)
for isamp in range(n_samples):
pce_samples[isamp] = samples[isamp]
#return samples in numpy array
return pce_samples
def UQTkGalerkinProjection(pc_model, f_evaluations):
"""
Obtain PC coefficients by Galerkin Projection via UQTk
Note: need to generalize this to allow projecting multiple variables at the time
Input:
pc_model : PC object with info about basis to project on
f_evaluations: 1D numpy array (vector) with function to be projected,
evaluated at the quadrature points
Output:
1D Numpy array with PC coefficients
"""
# Get parameters
if len(f_evaluations.shape) > 1:
print("This function can only project single variables for now")
exit(1)
npce = pc_model.GetNumberPCTerms()
nqp = f_evaluations.shape[0] # Number of quadrature points
# UQTk array for PC coefficients for one variable
c_k_1d_uqtk = uqtkarray.dblArray1D(npce, 0.0)
# UQTk array for function evaluations at quadrature points for that variable
f_uqtk = uqtkarray.dblArray1D(nqp, 0.0)
for ipt in range(nqp):
f_uqtk[ipt] = f_evaluations[ipt]
# Galerkin Projection
pc_model.GalerkProjection(f_uqtk, c_k_1d_uqtk)
# Put PC coefficients in numpy array
c_k = np.zeros(npce)
for ip in range(npce):
c_k[ip] = c_k_1d_uqtk[ip]
# Return numpy array of PC coefficients
return c_k
def UQTkStDv(pc_model, pc_coeffs):
"""
Compute Standard Deviation of a PCE through UQTk
Input:
pc_model: PC object with info about PCE
pc_coeffs: 1D numpy array with PCE coefficients
Output:
pc_stdv: Standard Deviation of the PCE
"""
# Info about PCE
n_pce = pc_model.GetNumberPCTerms()
# Create and fill UQTk array for PC coefficients
c_k_1d_uqtk = uqtkarray.dblArray1D(n_pce, 0.0)
for ip in range(n_pce):
c_k_1d_uqtk[ip] = pc_coeffs[ip]
pc_stdv = pc_model.StDv(c_k_1d_uqtk)
return pc_stdv
def UQTkMap2PCE(pc_model, rvs_in, verbose=0):
"""Obtain PC representation for the random variables that are described by samples.
Employ a Rosenblatt transformation to build a map between the input RVs and the space
of the PC germ.
Input:
pc_model: object with properties of the PCE to be constructed
rvs_in : numpy array with input RV samples. Each line is a sample. The columns
represent the dimensions of the input RV.
verbose : verbosity level (more output for higher values)
Output:
Numpy array with PC coefficients for each RV in the original rvs_in input
"""
# Dimensionality and number of samples of input RVs
ndim = rvs_in.shape[1]
nsamp = rvs_in.shape[0]
# Algorithm parameters
bw = -1 # KDE bandwidth for Rosenblatt (on interval 0.1)
iiout = 50 # interval for output to screen
# Number of PCE terms
npce = pc_model.GetNumberPCTerms()
# Get the default quadrature points
qdpts = uqtkarray.dblArray2D()
pc_model.GetQuadPoints(qdpts)
totquat = pc_model.GetNQuadPoints()
print("Total number of quadrature points =", totquat)
# Set up transpose of input data for the inverse Rosenblatt transformation in a UQTk array
ydata_t = uqtkarray.dblArray2D(ndim, nsamp)
ydata_t.setnpdblArray(np.asfortranarray(rvs_in.T))
# Set up numpy array for mapped quadrature points
invRosData = np.zeros((totquat, ndim))
# Map all quadrature points in chosen PC set to the distribution given by the data
# using the inverse Rosenblatt transformation
for ipt in range(totquat):
# print("Converting quadrature point #",ipt)
# Set up working arrays
quadunif = uqtkarray.dblArray1D(ndim, 0.0)
invRosData_1s = uqtkarray.dblArray1D(ndim, 0.0)
# First map each point to uniform[0,1]
# PCtoPC maps to [-1,1], which then gets remapped to [0,1]
for idim in range(ndim):
quadunif[idim] = (uqtktools.PCtoPC(
qdpts[ipt, idim], pc_model.GetPCType(), pc_model.GetAlpha(),
pc_model.GetBeta(), "LU", 0.0, 0.0) + 1.0) / 2.0
# Map each point from uniform[0,1] to the distribution given by the original samples via inverse Rosenblatt
if bw > 0:
uqtktools.invRos(quadunif, ydata_t, invRosData_1s, bw)
else:
uqtktools.invRos(quadunif, ydata_t, invRosData_1s)
# Store results
for idim in range(ndim):
invRosData[ipt, idim] = invRosData_1s[idim]
# Screen diagnostic output
if ((ipt + 1) % iiout == 0) or ipt == 0 or (ipt + 1) == totquat:
print("Inverse Rosenblatt for Galerkin projection:", (ipt + 1),
"/", totquat, "=", (ipt + 1) * 100 / totquat, "% completed")
# Get PC coefficients by Galerkin projection
# Set up numpy array for PC coefficients (one column for each transformed random variable)
c_k = np.zeros((npce, ndim))
# Project each random variable one by one
# Could replace some of this with the UQTkGalerkinProjection function below
for idim in range(ndim):
# UQTk array for PC coefficients for one variable
c_k_1d = uqtkarray.dblArray1D(npce, 0.0)
# UQTk array for map evaluations at quadrature points for that variable
invRosData_1d = uqtkarray.dblArray1D(totquat, 0.0)
# invRosData_1d.setnpdblArray(np.asfortranarray(invRosData[:,idim])
for ipt in range(totquat):
invRosData_1d[ipt] = invRosData[ipt, idim]
# Galerkin Projection
pc_model.GalerkProjection(invRosData_1d, c_k_1d)
# Put coefficients in full array
for ip in range(npce):
c_k[ip, idim] = c_k_1d[ip]
# Return numpy array of PC coefficients
return c_k
[7.745966692414834043e-01, -9.061798459386638527e-01],
[7.745966692414834043e-01, -7.745966692414832933e-01],
[7.745966692414834043e-01, -5.384693101056832187e-01],
[7.745966692414834043e-01, 0.000000000000000000e+00],
[7.745966692414834043e-01, 5.384693101056829967e-01],
[7.745966692414834043e-01, 7.745966692414834043e-01],
[7.745966692414834043e-01, 9.061798459386638527e-01],
[8.360311073266353254e-01, 0.000000000000000000e+00],
[9.061798459386638527e-01, -7.745966692414832933e-01],
[9.061798459386638527e-01, 0.000000000000000000e+00],
[9.061798459386638527e-01, 7.745966692414834043e-01],
[9.681602395076263079e-01, 0.000000000000000000e+00]])
# initiate uqtk arrays for quad points and weights
x = uqtkarray.dblArray2D()
w = uqtkarray.dblArray1D()
# create instance of quad class and output
# points and weights
print('Create an instance of Quad class')
ndim = 2
level = 3
q = uqtkquad.Quad('LU','sparse',ndim,level,0,1)
print('Now set and get the quadrature rule...')
q.SetRule()
q.GetRule(x,w)
# print out x and w
print('Displaying the quadrature points and weights:\n')
x_np = uqtk2numpy(x)
print(x_np)
# check if compiled self.__compiled = False self.compile() self.__cv_flag = False def compile(self,l_init=0.0,adaptive=0,optimal=1,scale=.1,verbose=0): ''' Setting up variables for the BCS algorithm. Most of the variables do not need to be set. Default settings are sufficient for more cases. See the C++ code for more information about variables. ''' # now we begin BCS routine # set work variables self.__newmindex_uqtk = uqtkarray.intArray2D() # for uporder iteration self.__sigma2_p = uqtktools.new_doublep() # initial noise variance self.__lambda_init = uqtkarray.dblArray1D() # hierarchical prior parameter self.__adaptive, self.__optimal, self.__scale, self.__verbose = adaptive,optimal,scale,verbose self.__weights_uqtk = uqtkarray.dblArray1D() # weights/ coefficients for basis self.__used_uqtk = uqtkarray.intArray1D() # index of weights retained (nonzero) self.__errbars_uqtk = uqtkarray.dblArray1D() # error bars for each weight self.__nextbasis_uqtk = uqtkarray.dblArray1D() # if adaptive self.__alpha_uqtk = uqtkarray.dblArray1D() # prior hyperparameter (1/gamma) self.__lambda_p = uqtktools.new_doublep() uqtktools.doublep_assign(self.__lambda_p,l_init) self.__compiled = True def leastsq(self,X,y): ''' perform simple least squares based on the original
# try to import uqtk array library and # functions to convert between uqtk and numpy arrays try: import uqtkarray from uqtkarray import numpy2uqtk from uqtkarray import uqtk2numpy except ImportError: print "PyUQTk array module not found" print "If installing in a directory other than the build directory, make sure PYTHONPATH includes the install directory" import unittest ''' Test converting 1d numpy array to 1d uqtk array ''' # create 1d array N = 35 x = uqtkarray.dblArray1D(N,0) # create 1d numpy array x_np = random.randn(N) # set uqtk array to numpy array x.setnpdblArray(x_np) # test to make sure array elements are the same for i in range(N): assert x[i] == x_np[i] ''' Test converting 2d numpy array to 2d uqtk array ''' # create 2d array in uqtk m = 100 n = 3
