First commit

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2025-06-22 00:31:33 +02:00
parent a52c20d1fb
commit 4bdbcad256
110 changed files with 31991 additions and 1 deletions

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from __future__ import print_function
from array import array
import sys
try:
import numpy as np
import scipy
from scipy import sparse
except:
scipy = None
__all__ = ['svm_read_problem', 'evaluations', 'csr_find_scale_param', 'csr_scale']
def svm_read_problem(data_source, return_scipy=False):
"""
svm_read_problem(data_source, return_scipy=False) -> [y, x], y: list, x: list of dictionary
svm_read_problem(data_source, return_scipy=True) -> [y, x], y: ndarray, x: csr_matrix
Read LIBSVM-format data from data_source and return labels y
and data instances x.
"""
if scipy != None and return_scipy:
prob_y = array('d')
prob_x = array('d')
row_ptr = array('l', [0])
col_idx = array('l')
else:
prob_y = []
prob_x = []
row_ptr = [0]
col_idx = []
indx_start = 1
if hasattr(data_source, "read"):
file = data_source
else:
file = open(data_source)
try:
for line in file:
line = line.split(None, 1)
# In case an instance with all zero features
if len(line) == 1: line += ['']
label, features = line
prob_y.append(float(label))
if scipy != None and return_scipy:
nz = 0
for e in features.split():
ind, val = e.split(":")
if ind == '0':
indx_start = 0
val = float(val)
if val != 0:
col_idx.append(int(ind)-indx_start)
prob_x.append(val)
nz += 1
row_ptr.append(row_ptr[-1]+nz)
else:
xi = {}
for e in features.split():
ind, val = e.split(":")
xi[int(ind)] = float(val)
prob_x += [xi]
except Exception as err_msg:
raise err_msg
finally:
if not hasattr(data_source, "read"):
# close file only if it was created by us
file.close()
if scipy != None and return_scipy:
prob_y = np.frombuffer(prob_y, dtype='d')
prob_x = np.frombuffer(prob_x, dtype='d')
col_idx = np.frombuffer(col_idx, dtype='l')
row_ptr = np.frombuffer(row_ptr, dtype='l')
prob_x = sparse.csr_matrix((prob_x, col_idx, row_ptr))
return (prob_y, prob_x)
def evaluations_scipy(ty, pv):
"""
evaluations_scipy(ty, pv) -> (ACC, MSE, SCC)
ty, pv: ndarray
Calculate accuracy, mean squared error and squared correlation coefficient
using the true values (ty) and predicted values (pv).
"""
if not (scipy != None and isinstance(ty, np.ndarray) and isinstance(pv, np.ndarray)):
raise TypeError("type of ty and pv must be ndarray")
if len(ty) != len(pv):
raise ValueError("len(ty) must be equal to len(pv)")
ACC = 100.0*(ty == pv).mean()
MSE = ((ty - pv)**2).mean()
l = len(ty)
sumv = pv.sum()
sumy = ty.sum()
sumvy = (pv*ty).sum()
sumvv = (pv*pv).sum()
sumyy = (ty*ty).sum()
with np.errstate(all = 'raise'):
try:
SCC = ((l*sumvy-sumv*sumy)*(l*sumvy-sumv*sumy))/((l*sumvv-sumv*sumv)*(l*sumyy-sumy*sumy))
except:
SCC = float('nan')
return (float(ACC), float(MSE), float(SCC))
def evaluations(ty, pv, useScipy = True):
"""
evaluations(ty, pv, useScipy) -> (ACC, MSE, SCC)
ty, pv: list, tuple or ndarray
useScipy: convert ty, pv to ndarray, and use scipy functions for the evaluation
Calculate accuracy, mean squared error and squared correlation coefficient
using the true values (ty) and predicted values (pv).
"""
if scipy != None and useScipy:
return evaluations_scipy(np.asarray(ty), np.asarray(pv))
if len(ty) != len(pv):
raise ValueError("len(ty) must be equal to len(pv)")
total_correct = total_error = 0
sumv = sumy = sumvv = sumyy = sumvy = 0
for v, y in zip(pv, ty):
if y == v:
total_correct += 1
total_error += (v-y)*(v-y)
sumv += v
sumy += y
sumvv += v*v
sumyy += y*y
sumvy += v*y
l = len(ty)
ACC = 100.0*total_correct/l
MSE = total_error/l
try:
SCC = ((l*sumvy-sumv*sumy)*(l*sumvy-sumv*sumy))/((l*sumvv-sumv*sumv)*(l*sumyy-sumy*sumy))
except:
SCC = float('nan')
return (float(ACC), float(MSE), float(SCC))
def csr_find_scale_param(x, lower=-1, upper=1):
assert isinstance(x, sparse.csr_matrix)
assert lower < upper
l, n = x.shape
feat_min = x.min(axis=0).toarray().flatten()
feat_max = x.max(axis=0).toarray().flatten()
coef = (feat_max - feat_min) / (upper - lower)
coef[coef != 0] = 1.0 / coef[coef != 0]
# (x - ones(l,1) * feat_min') * diag(coef) + lower
# = x * diag(coef) - ones(l, 1) * (feat_min' * diag(coef)) + lower
# = x * diag(coef) + ones(l, 1) * (-feat_min' * diag(coef) + lower)
# = x * diag(coef) + ones(l, 1) * offset'
offset = -feat_min * coef + lower
offset[coef == 0] = 0
if sum(offset != 0) * l > 3 * x.getnnz():
print(
"WARNING: The #nonzeros of the scaled data is at least 2 times larger than the original one.\n"
"If feature values are non-negative and sparse, set lower=0 rather than the default lower=-1.",
file=sys.stderr)
return {'coef':coef, 'offset':offset}
def csr_scale(x, scale_param):
assert isinstance(x, sparse.csr_matrix)
offset = scale_param['offset']
coef = scale_param['coef']
assert len(coef) == len(offset)
l, n = x.shape
if not n == len(coef):
print("WARNING: The dimension of scaling parameters and feature number do not match.", file=sys.stderr)
coef = coef.resize(n) # zeros padded if n > len(coef)
offset = offset.resize(n)
# scaled_x = x * diag(coef) + ones(l, 1) * offset'
offset = sparse.csr_matrix(offset.reshape(1, n))
offset = sparse.vstack([offset] * l, format='csr', dtype=x.dtype)
scaled_x = x.dot(sparse.diags(coef, 0, shape=(n, n))) + offset
if scaled_x.getnnz() > x.getnnz():
print(
"WARNING: original #nonzeros %d\n" % x.getnnz() +
" > new #nonzeros %d\n" % scaled_x.getnnz() +
"If feature values are non-negative and sparse, get scale_param by setting lower=0 rather than the default lower=-1.",
file=sys.stderr)
return scaled_x

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from ctypes import *
from ctypes.util import find_library
from os import path
from glob import glob
from enum import IntEnum
import sys
try:
import numpy as np
import scipy
from scipy import sparse
except:
scipy = None
if sys.version_info[0] < 3:
range = xrange
from itertools import izip as zip
__all__ = ['libsvm', 'svm_problem', 'svm_parameter',
'toPyModel', 'gen_svm_nodearray', 'print_null', 'svm_node', 'svm_forms',
'PRINT_STRING_FUN', 'kernel_names', 'c_double', 'svm_model']
try:
dirname = path.dirname(path.abspath(__file__))
dynamic_lib_name = 'clib.cp*'
path_to_so = glob(path.join(dirname, dynamic_lib_name))[0]
libsvm = CDLL(path_to_so)
except:
try:
if sys.platform == 'win32':
libsvm = CDLL(path.join(dirname, r'..\..\windows\libsvm.dll'))
else:
libsvm = CDLL(path.join(dirname, '../../libsvm.so.4'))
except:
# For unix the prefix 'lib' is not considered.
if find_library('svm'):
libsvm = CDLL(find_library('svm'))
elif find_library('libsvm'):
libsvm = CDLL(find_library('libsvm'))
else:
raise Exception('LIBSVM library not found.')
class svm_forms(IntEnum):
C_SVC = 0
NU_SVC = 1
ONE_CLASS = 2
EPSILON_SVR = 3
NU_SVR = 4
class kernel_names(IntEnum):
LINEAR = 0
POLY = 1
RBF = 2
SIGMOID = 3
PRECOMPUTED = 4
PRINT_STRING_FUN = CFUNCTYPE(None, c_char_p)
def print_null(s):
return
# In multi-threading, all threads share the same memory space of
# the dynamic library (libsvm). Thus, we use a module-level
# variable to keep a reference to ctypes print_null, preventing
# python from garbage collecting it in thread B while thread A
# still needs it. Check the usage of svm_set_print_string_function()
# in LIBSVM README for details.
ctypes_print_null = PRINT_STRING_FUN(print_null)
def genFields(names, types):
return list(zip(names, types))
def fillprototype(f, restype, argtypes):
f.restype = restype
f.argtypes = argtypes
class svm_node(Structure):
_names = ["index", "value"]
_types = [c_int, c_double]
_fields_ = genFields(_names, _types)
def __init__(self, index=-1, value=0):
self.index, self.value = index, value
def __str__(self):
return '%d:%g' % (self.index, self.value)
def gen_svm_nodearray(xi, feature_max=None, isKernel=False):
if feature_max:
assert(isinstance(feature_max, int))
xi_shift = 0 # ensure correct indices of xi
if scipy and isinstance(xi, tuple) and len(xi) == 2\
and isinstance(xi[0], np.ndarray) and isinstance(xi[1], np.ndarray): # for a sparse vector
if not isKernel:
index_range = xi[0] + 1 # index starts from 1
else:
index_range = xi[0] # index starts from 0 for precomputed kernel
if feature_max:
index_range = index_range[np.where(index_range <= feature_max)]
elif scipy and isinstance(xi, np.ndarray):
if not isKernel:
xi_shift = 1
index_range = xi.nonzero()[0] + 1 # index starts from 1
else:
index_range = np.arange(0, len(xi)) # index starts from 0 for precomputed kernel
if feature_max:
index_range = index_range[np.where(index_range <= feature_max)]
elif isinstance(xi, (dict, list, tuple)):
if isinstance(xi, dict):
index_range = sorted(xi.keys())
elif isinstance(xi, (list, tuple)):
if not isKernel:
xi_shift = 1
index_range = range(1, len(xi) + 1) # index starts from 1
else:
index_range = range(0, len(xi)) # index starts from 0 for precomputed kernel
if feature_max:
index_range = list(filter(lambda j: j <= feature_max, index_range))
if not isKernel:
index_range = list(filter(lambda j:xi[j-xi_shift] != 0, index_range))
else:
raise TypeError('xi should be a dictionary, list, tuple, 1-d numpy array, or tuple of (index, data)')
ret = (svm_node*(len(index_range)+1))()
ret[-1].index = -1
if scipy and isinstance(xi, tuple) and len(xi) == 2\
and isinstance(xi[0], np.ndarray) and isinstance(xi[1], np.ndarray): # for a sparse vector
# since xi=(indices, values), we must sort them simultaneously.
for idx, arg in enumerate(np.argsort(index_range)):
ret[idx].index = index_range[arg]
ret[idx].value = (xi[1])[arg]
else:
for idx, j in enumerate(index_range):
ret[idx].index = j
ret[idx].value = xi[j - xi_shift]
max_idx = 0
if len(index_range) > 0:
max_idx = index_range[-1]
return ret, max_idx
try:
from numba import jit
jit_enabled = True
except:
# We need to support two cases: when jit is called with no arguments, and when jit is called with
# a keyword argument.
def jit(func=None, *args, **kwargs):
if func is None:
# This handles the case where jit is used with parentheses: @jit(nopython=True)
return lambda x: x
else:
# This handles the case where jit is used without parentheses: @jit
return func
jit_enabled = False
@jit(nopython=True)
def csr_to_problem_jit(l, x_val, x_ind, x_rowptr, prob_val, prob_ind, prob_rowptr, indx_start):
for i in range(l):
b1,e1 = x_rowptr[i], x_rowptr[i+1]
b2,e2 = prob_rowptr[i], prob_rowptr[i+1]-1
for j in range(b1,e1):
prob_ind[j-b1+b2] = x_ind[j]+indx_start
prob_val[j-b1+b2] = x_val[j]
def csr_to_problem_nojit(l, x_val, x_ind, x_rowptr, prob_val, prob_ind, prob_rowptr, indx_start):
for i in range(l):
x_slice = slice(x_rowptr[i], x_rowptr[i+1])
prob_slice = slice(prob_rowptr[i], prob_rowptr[i+1]-1)
prob_ind[prob_slice] = x_ind[x_slice]+indx_start
prob_val[prob_slice] = x_val[x_slice]
def csr_to_problem(x, prob, isKernel):
if not x.has_sorted_indices:
x.sort_indices()
# Extra space for termination node and (possibly) bias term
x_space = prob.x_space = np.empty((x.nnz+x.shape[0]), dtype=svm_node)
# rowptr has to be a 64bit integer because it will later be used for pointer arithmetic,
# which overflows when the added pointer points to an address that is numerically high.
prob.rowptr = x.indptr.astype(np.int64, copy=True)
prob.rowptr[1:] += np.arange(1,x.shape[0]+1)
prob_ind = x_space["index"]
prob_val = x_space["value"]
prob_ind[:] = -1
if not isKernel:
indx_start = 1 # index starts from 1
else:
indx_start = 0 # index starts from 0 for precomputed kernel
if jit_enabled:
csr_to_problem_jit(x.shape[0], x.data, x.indices, x.indptr, prob_val, prob_ind, prob.rowptr, indx_start)
else:
csr_to_problem_nojit(x.shape[0], x.data, x.indices, x.indptr, prob_val, prob_ind, prob.rowptr, indx_start)
class svm_problem(Structure):
_names = ["l", "y", "x"]
_types = [c_int, POINTER(c_double), POINTER(POINTER(svm_node))]
_fields_ = genFields(_names, _types)
def __init__(self, y, x, isKernel=False):
if (not isinstance(y, (list, tuple))) and (not (scipy and isinstance(y, np.ndarray))):
raise TypeError("type of y: {0} is not supported!".format(type(y)))
if isinstance(x, (list, tuple)):
if len(y) != len(x):
raise ValueError("len(y) != len(x)")
elif scipy != None and isinstance(x, (np.ndarray, sparse.spmatrix)):
if len(y) != x.shape[0]:
raise ValueError("len(y) != len(x)")
if isinstance(x, np.ndarray):
x = np.ascontiguousarray(x) # enforce row-major
if isinstance(x, sparse.spmatrix):
x = x.tocsr()
pass
else:
raise TypeError("type of x: {0} is not supported!".format(type(x)))
self.l = l = len(y)
max_idx = 0
x_space = self.x_space = []
if scipy != None and isinstance(x, sparse.csr_matrix):
csr_to_problem(x, self, isKernel)
max_idx = x.shape[1]
else:
for i, xi in enumerate(x):
tmp_xi, tmp_idx = gen_svm_nodearray(xi,isKernel=isKernel)
x_space += [tmp_xi]
max_idx = max(max_idx, tmp_idx)
self.n = max_idx
self.y = (c_double * l)()
if scipy != None and isinstance(y, np.ndarray):
np.ctypeslib.as_array(self.y, (self.l,))[:] = y
else:
for i, yi in enumerate(y): self.y[i] = yi
self.x = (POINTER(svm_node) * l)()
if scipy != None and isinstance(x, sparse.csr_matrix):
base = addressof(self.x_space.ctypes.data_as(POINTER(svm_node))[0])
x_ptr = cast(self.x, POINTER(c_uint64))
x_ptr = np.ctypeslib.as_array(x_ptr,(self.l,))
x_ptr[:] = self.rowptr[:-1]*sizeof(svm_node)+base
else:
for i, xi in enumerate(self.x_space): self.x[i] = xi
class svm_parameter(Structure):
_names = ["svm_type", "kernel_type", "degree", "gamma", "coef0",
"cache_size", "eps", "C", "nr_weight", "weight_label", "weight",
"nu", "p", "shrinking", "probability"]
_types = [c_int, c_int, c_int, c_double, c_double,
c_double, c_double, c_double, c_int, POINTER(c_int), POINTER(c_double),
c_double, c_double, c_int, c_int]
_fields_ = genFields(_names, _types)
def __init__(self, options = None):
if options == None:
options = ''
self.parse_options(options)
def __str__(self):
s = ''
attrs = svm_parameter._names + list(self.__dict__.keys())
values = map(lambda attr: getattr(self, attr), attrs)
for attr, val in zip(attrs, values):
s += (' %s: %s\n' % (attr, val))
s = s.strip()
return s
def set_to_default_values(self):
self.svm_type = svm_forms.C_SVC;
self.kernel_type = kernel_names.RBF
self.degree = 3
self.gamma = 0
self.coef0 = 0
self.nu = 0.5
self.cache_size = 100
self.C = 1
self.eps = 0.001
self.p = 0.1
self.shrinking = 1
self.probability = 0
self.nr_weight = 0
self.weight_label = None
self.weight = None
self.cross_validation = False
self.nr_fold = 0
self.print_func = cast(None, PRINT_STRING_FUN)
def parse_options(self, options):
if isinstance(options, list):
argv = options
elif isinstance(options, str):
argv = options.split()
else:
raise TypeError("arg 1 should be a list or a str.")
self.set_to_default_values()
self.print_func = cast(None, PRINT_STRING_FUN)
weight_label = []
weight = []
i = 0
while i < len(argv):
if argv[i] == "-s":
i = i + 1
self.svm_type = svm_forms(int(argv[i]))
elif argv[i] == "-t":
i = i + 1
self.kernel_type = kernel_names(int(argv[i]))
elif argv[i] == "-d":
i = i + 1
self.degree = int(argv[i])
elif argv[i] == "-g":
i = i + 1
self.gamma = float(argv[i])
elif argv[i] == "-r":
i = i + 1
self.coef0 = float(argv[i])
elif argv[i] == "-n":
i = i + 1
self.nu = float(argv[i])
elif argv[i] == "-m":
i = i + 1
self.cache_size = float(argv[i])
elif argv[i] == "-c":
i = i + 1
self.C = float(argv[i])
elif argv[i] == "-e":
i = i + 1
self.eps = float(argv[i])
elif argv[i] == "-p":
i = i + 1
self.p = float(argv[i])
elif argv[i] == "-h":
i = i + 1
self.shrinking = int(argv[i])
elif argv[i] == "-b":
i = i + 1
self.probability = int(argv[i])
elif argv[i] == "-q":
self.print_func = ctypes_print_null
elif argv[i] == "-v":
i = i + 1
self.cross_validation = 1
self.nr_fold = int(argv[i])
if self.nr_fold < 2:
raise ValueError("n-fold cross validation: n must >= 2")
elif argv[i].startswith("-w"):
i = i + 1
self.nr_weight += 1
weight_label += [int(argv[i-1][2:])]
weight += [float(argv[i])]
else:
raise ValueError("Wrong options")
i += 1
libsvm.svm_set_print_string_function(self.print_func)
self.weight_label = (c_int*self.nr_weight)()
self.weight = (c_double*self.nr_weight)()
for i in range(self.nr_weight):
self.weight[i] = weight[i]
self.weight_label[i] = weight_label[i]
class svm_model(Structure):
_names = ['param', 'nr_class', 'l', 'SV', 'sv_coef', 'rho',
'probA', 'probB', 'prob_density_marks', 'sv_indices',
'label', 'nSV', 'free_sv']
_types = [svm_parameter, c_int, c_int, POINTER(POINTER(svm_node)),
POINTER(POINTER(c_double)), POINTER(c_double),
POINTER(c_double), POINTER(c_double), POINTER(c_double),
POINTER(c_int), POINTER(c_int), POINTER(c_int), c_int]
_fields_ = genFields(_names, _types)
def __init__(self):
self.__createfrom__ = 'python'
def __del__(self):
# free memory created by C to avoid memory leak
if hasattr(self, '__createfrom__') and self.__createfrom__ == 'C':
libsvm.svm_free_and_destroy_model(pointer(pointer(self)))
def get_svm_type(self):
return libsvm.svm_get_svm_type(self)
def get_nr_class(self):
return libsvm.svm_get_nr_class(self)
def get_svr_probability(self):
return libsvm.svm_get_svr_probability(self)
def get_labels(self):
nr_class = self.get_nr_class()
labels = (c_int * nr_class)()
libsvm.svm_get_labels(self, labels)
return labels[:nr_class]
def get_sv_indices(self):
total_sv = self.get_nr_sv()
sv_indices = (c_int * total_sv)()
libsvm.svm_get_sv_indices(self, sv_indices)
return sv_indices[:total_sv]
def get_nr_sv(self):
return libsvm.svm_get_nr_sv(self)
def is_probability_model(self):
return (libsvm.svm_check_probability_model(self) == 1)
def get_sv_coef(self):
return [tuple(self.sv_coef[j][i] for j in range(self.nr_class - 1))
for i in range(self.l)]
def get_SV(self):
result = []
for sparse_sv in self.SV[:self.l]:
row = dict()
i = 0
while True:
if sparse_sv[i].index == -1:
break
row[sparse_sv[i].index] = sparse_sv[i].value
i += 1
result.append(row)
return result
def toPyModel(model_ptr):
"""
toPyModel(model_ptr) -> svm_model
Convert a ctypes POINTER(svm_model) to a Python svm_model
"""
if bool(model_ptr) == False:
raise ValueError("Null pointer")
m = model_ptr.contents
m.__createfrom__ = 'C'
return m
fillprototype(libsvm.svm_train, POINTER(svm_model), [POINTER(svm_problem), POINTER(svm_parameter)])
fillprototype(libsvm.svm_cross_validation, None, [POINTER(svm_problem), POINTER(svm_parameter), c_int, POINTER(c_double)])
fillprototype(libsvm.svm_save_model, c_int, [c_char_p, POINTER(svm_model)])
fillprototype(libsvm.svm_load_model, POINTER(svm_model), [c_char_p])
fillprototype(libsvm.svm_get_svm_type, c_int, [POINTER(svm_model)])
fillprototype(libsvm.svm_get_nr_class, c_int, [POINTER(svm_model)])
fillprototype(libsvm.svm_get_labels, None, [POINTER(svm_model), POINTER(c_int)])
fillprototype(libsvm.svm_get_sv_indices, None, [POINTER(svm_model), POINTER(c_int)])
fillprototype(libsvm.svm_get_nr_sv, c_int, [POINTER(svm_model)])
fillprototype(libsvm.svm_get_svr_probability, c_double, [POINTER(svm_model)])
fillprototype(libsvm.svm_predict_values, c_double, [POINTER(svm_model), POINTER(svm_node), POINTER(c_double)])
fillprototype(libsvm.svm_predict, c_double, [POINTER(svm_model), POINTER(svm_node)])
fillprototype(libsvm.svm_predict_probability, c_double, [POINTER(svm_model), POINTER(svm_node), POINTER(c_double)])
fillprototype(libsvm.svm_free_model_content, None, [POINTER(svm_model)])
fillprototype(libsvm.svm_free_and_destroy_model, None, [POINTER(POINTER(svm_model))])
fillprototype(libsvm.svm_destroy_param, None, [POINTER(svm_parameter)])
fillprototype(libsvm.svm_check_parameter, c_char_p, [POINTER(svm_problem), POINTER(svm_parameter)])
fillprototype(libsvm.svm_check_probability_model, c_int, [POINTER(svm_model)])
fillprototype(libsvm.svm_set_print_string_function, None, [PRINT_STRING_FUN])

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@@ -0,0 +1,263 @@
import os, sys
from .svm import *
from .svm import __all__ as svm_all
from .commonutil import *
from .commonutil import __all__ as common_all
try:
import numpy as np
import scipy
from scipy import sparse
except:
scipy = None
if sys.version_info[0] < 3:
range = xrange
from itertools import izip as zip
_cstr = lambda s: s.encode("utf-8") if isinstance(s,unicode) else str(s)
else:
_cstr = lambda s: bytes(s, "utf-8")
__all__ = ['svm_load_model', 'svm_predict', 'svm_save_model', 'svm_train'] + svm_all + common_all
def svm_load_model(model_file_name):
"""
svm_load_model(model_file_name) -> model
Load a LIBSVM model from model_file_name and return.
"""
model = libsvm.svm_load_model(_cstr(model_file_name))
if not model:
print("can't open model file %s" % model_file_name)
return None
model = toPyModel(model)
return model
def svm_save_model(model_file_name, model):
"""
svm_save_model(model_file_name, model) -> None
Save a LIBSVM model to the file model_file_name.
"""
libsvm.svm_save_model(_cstr(model_file_name), model)
def svm_train(arg1, arg2=None, arg3=None):
"""
svm_train(y, x [, options]) -> model | ACC | MSE
y: a list/tuple/ndarray of l true labels (type must be int/double).
x: 1. a list/tuple of l training instances. Feature vector of
each training instance is a list/tuple or dictionary.
2. an l * n numpy ndarray or scipy spmatrix (n: number of features).
svm_train(prob [, options]) -> model | ACC | MSE
svm_train(prob, param) -> model | ACC| MSE
Train an SVM model from data (y, x) or an svm_problem prob using
'options' or an svm_parameter param.
If '-v' is specified in 'options' (i.e., cross validation)
either accuracy (ACC) or mean-squared error (MSE) is returned.
options:
-s svm_type : set type of SVM (default 0)
0 -- C-SVC (multi-class classification)
1 -- nu-SVC (multi-class classification)
2 -- one-class SVM
3 -- epsilon-SVR (regression)
4 -- nu-SVR (regression)
-t kernel_type : set type of kernel function (default 2)
0 -- linear: u'*v
1 -- polynomial: (gamma*u'*v + coef0)^degree
2 -- radial basis function: exp(-gamma*|u-v|^2)
3 -- sigmoid: tanh(gamma*u'*v + coef0)
4 -- precomputed kernel (kernel values in training_set_file)
-d degree : set degree in kernel function (default 3)
-g gamma : set gamma in kernel function (default 1/num_features)
-r coef0 : set coef0 in kernel function (default 0)
-c cost : set the parameter C of C-SVC, epsilon-SVR, and nu-SVR (default 1)
-n nu : set the parameter nu of nu-SVC, one-class SVM, and nu-SVR (default 0.5)
-p epsilon : set the epsilon in loss function of epsilon-SVR (default 0.1)
-m cachesize : set cache memory size in MB (default 100)
-e epsilon : set tolerance of termination criterion (default 0.001)
-h shrinking : whether to use the shrinking heuristics, 0 or 1 (default 1)
-b probability_estimates : whether to train a model for probability estimates, 0 or 1 (default 0)
-wi weight : set the parameter C of class i to weight*C, for C-SVC (default 1)
-v n: n-fold cross validation mode
-q : quiet mode (no outputs)
"""
prob, param = None, None
if isinstance(arg1, (list, tuple)) or (scipy and isinstance(arg1, np.ndarray)):
assert isinstance(arg2, (list, tuple)) or (scipy and isinstance(arg2, (np.ndarray, sparse.spmatrix)))
y, x, options = arg1, arg2, arg3
param = svm_parameter(options)
prob = svm_problem(y, x, isKernel=(param.kernel_type == kernel_names.PRECOMPUTED))
elif isinstance(arg1, svm_problem):
prob = arg1
if isinstance(arg2, svm_parameter):
param = arg2
else:
param = svm_parameter(arg2)
if prob == None or param == None:
raise TypeError("Wrong types for the arguments")
if param.kernel_type == kernel_names.PRECOMPUTED:
for i in range(prob.l):
xi = prob.x[i]
idx, val = xi[0].index, xi[0].value
if idx != 0:
raise ValueError('Wrong input format: first column must be 0:sample_serial_number')
if val <= 0 or val > prob.n:
raise ValueError('Wrong input format: sample_serial_number out of range')
if param.gamma == 0 and prob.n > 0:
param.gamma = 1.0 / prob.n
libsvm.svm_set_print_string_function(param.print_func)
err_msg = libsvm.svm_check_parameter(prob, param)
if err_msg:
raise ValueError('Error: %s' % err_msg)
if param.cross_validation:
l, nr_fold = prob.l, param.nr_fold
target = (c_double * l)()
libsvm.svm_cross_validation(prob, param, nr_fold, target)
ACC, MSE, SCC = evaluations(prob.y[:l], target[:l])
if param.svm_type in [svm_forms.EPSILON_SVR, svm_forms.NU_SVR]:
print("Cross Validation Mean squared error = %g" % MSE)
print("Cross Validation Squared correlation coefficient = %g" % SCC)
return MSE
else:
print("Cross Validation Accuracy = %g%%" % ACC)
return ACC
else:
m = libsvm.svm_train(prob, param)
m = toPyModel(m)
# If prob is destroyed, data including SVs pointed by m can remain.
m.x_space = prob.x_space
return m
def svm_predict(y, x, m, options=""):
"""
svm_predict(y, x, m [, options]) -> (p_labels, p_acc, p_vals)
y: a list/tuple/ndarray of l true labels (type must be int/double).
It is used for calculating the accuracy. Use [] if true labels are
unavailable.
x: 1. a list/tuple of l training instances. Feature vector of
each training instance is a list/tuple or dictionary.
2. an l * n numpy ndarray or scipy spmatrix (n: number of features).
Predict data (y, x) with the SVM model m.
options:
-b probability_estimates: whether to predict probability estimates,
0 or 1 (default 0).
-q : quiet mode (no outputs).
The return tuple contains
p_labels: a list of predicted labels
p_acc: a tuple including accuracy (for classification), mean-squared
error, and squared correlation coefficient (for regression).
p_vals: a list of decision values or probability estimates (if '-b 1'
is specified). If k is the number of classes, for decision values,
each element includes results of predicting k(k-1)/2 binary-class
SVMs. For probabilities, each element contains k values indicating
the probability that the testing instance is in each class.
Note that the order of classes here is the same as 'model.label'
field in the model structure.
"""
def info(s):
print(s)
if scipy and isinstance(x, np.ndarray):
x = np.ascontiguousarray(x) # enforce row-major
elif sparse and isinstance(x, sparse.spmatrix):
x = x.tocsr()
elif not isinstance(x, (list, tuple)):
raise TypeError("type of x: {0} is not supported!".format(type(x)))
if (not isinstance(y, (list, tuple))) and (not (scipy and isinstance(y, np.ndarray))):
raise TypeError("type of y: {0} is not supported!".format(type(y)))
predict_probability = 0
argv = options.split()
i = 0
while i < len(argv):
if argv[i] == '-b':
i += 1
predict_probability = int(argv[i])
elif argv[i] == '-q':
info = print_null
else:
raise ValueError("Wrong options")
i+=1
svm_type = m.get_svm_type()
is_prob_model = m.is_probability_model()
nr_class = m.get_nr_class()
pred_labels = []
pred_values = []
if scipy and isinstance(x, sparse.spmatrix):
nr_instance = x.shape[0]
else:
nr_instance = len(x)
if predict_probability:
if not is_prob_model:
raise ValueError("Model does not support probabiliy estimates")
if svm_type in [svm_forms.NU_SVR, svm_forms.EPSILON_SVR]:
info("Prob. model for test data: target value = predicted value + z,\n"
"z: Laplace distribution e^(-|z|/sigma)/(2sigma),sigma=%g" % m.get_svr_probability());
nr_class = 0
prob_estimates = (c_double * nr_class)()
for i in range(nr_instance):
if scipy and isinstance(x, sparse.spmatrix):
indslice = slice(x.indptr[i], x.indptr[i+1])
xi, idx = gen_svm_nodearray((x.indices[indslice], x.data[indslice]), isKernel=(m.param.kernel_type == kernel_names.PRECOMPUTED))
else:
xi, idx = gen_svm_nodearray(x[i], isKernel=(m.param.kernel_type == kernel_names.PRECOMPUTED))
label = libsvm.svm_predict_probability(m, xi, prob_estimates)
values = prob_estimates[:nr_class]
pred_labels += [label]
pred_values += [values]
else:
if is_prob_model:
info("Model supports probability estimates, but disabled in predicton.")
if svm_type in [svm_forms.ONE_CLASS, svm_forms.EPSILON_SVR, svm_forms.NU_SVC]:
nr_classifier = 1
else:
nr_classifier = nr_class*(nr_class-1)//2
dec_values = (c_double * nr_classifier)()
for i in range(nr_instance):
if scipy and isinstance(x, sparse.spmatrix):
indslice = slice(x.indptr[i], x.indptr[i+1])
xi, idx = gen_svm_nodearray((x.indices[indslice], x.data[indslice]), isKernel=(m.param.kernel_type == kernel_names.PRECOMPUTED))
else:
xi, idx = gen_svm_nodearray(x[i], isKernel=(m.param.kernel_type == kernel_names.PRECOMPUTED))
label = libsvm.svm_predict_values(m, xi, dec_values)
if(nr_class == 1):
values = [1]
else:
values = dec_values[:nr_classifier]
pred_labels += [label]
pred_values += [values]
if len(y) == 0:
y = [0] * nr_instance
ACC, MSE, SCC = evaluations(y, pred_labels)
if svm_type in [svm_forms.EPSILON_SVR, svm_forms.NU_SVR]:
info("Mean squared error = %g (regression)" % MSE)
info("Squared correlation coefficient = %g (regression)" % SCC)
else:
info("Accuracy = %g%% (%d/%d) (classification)" % (ACC, int(round(nr_instance*ACC/100)), nr_instance))
return pred_labels, (ACC, MSE, SCC), pred_values