forked from sjwhitworth/golearn
/
liblinear.go
155 lines (135 loc) · 3.33 KB
/
liblinear.go
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package linear_models
/*
#include "linear.h"
*/
import "C"
import "fmt"
import "unsafe"
type Problem struct {
c_prob C.struct_problem
}
type Parameter struct {
c_param C.struct_parameter
}
type Model struct {
c_model unsafe.Pointer
}
const (
L2R_LR = C.L2R_LR
L2R_L2LOSS_SVC_DUAL = C.L2R_L2LOSS_SVC_DUAL
L2R_L2LOSS_SVC = C.L2R_L2LOSS_SVC
L2R_L1LOSS_SVC_DUAL = C.L2R_L1LOSS_SVC_DUAL
MCSVM_CS = C.MCSVM_CS
L1R_L2LOSS_SVC = C.L1R_L2LOSS_SVC
L1R_LR = C.L1R_LR
L2R_LR_DUAL = C.L2R_LR_DUAL
)
func NewParameter(solver_type int, C float64, eps float64) *Parameter {
param := Parameter{}
param.c_param.solver_type = C.int(solver_type)
param.c_param.eps = C.double(eps)
param.c_param.C = C.double(C)
param.c_param.nr_weight = C.int(0)
param.c_param.weight_label = nil
param.c_param.weight = nil
return ¶m
}
func NewProblem(X [][]float64, y []float64, bias float64) *Problem {
prob := Problem{}
prob.c_prob.l = C.int(len(X))
prob.c_prob.n = C.int(len(X[0]) + 1)
prob.c_prob.x = convert_features(X, bias)
c_y := make([]C.double, len(y))
for i := 0; i < len(y); i++ {
c_y[i] = C.double(y[i])
}
prob.c_prob.y = &c_y[0]
prob.c_prob.bias = C.double(-1)
return &prob
}
func Train(prob *Problem, param *Parameter) *Model {
libLinearHookPrintFunc() // Sets up logging
tmpCProb := &prob.c_prob
tmpCParam := ¶m.c_param
return &Model{unsafe.Pointer(C.train(tmpCProb, tmpCParam))}
}
func Export(model *Model, filePath string) error {
status := C.save_model(C.CString(filePath), (*C.struct_model)(model.c_model))
if status != 0 {
return fmt.Errorf("Problem occured during export to %s (status was %d)", filePath, status)
}
return nil
}
func Load(model *Model, filePath string) error {
model.c_model = unsafe.Pointer(C.load_model(C.CString(filePath)))
if model.c_model == nil {
return fmt.Errorf("Something went wrong")
}
return nil
}
func Predict(model *Model, x []float64) float64 {
c_x := convert_vector(x, 0)
c_y := C.predict((*C.struct_model)(model.c_model), c_x)
y := float64(c_y)
return y
}
func convert_vector(x []float64, bias float64) *C.struct_feature_node {
n_ele := 0
for i := 0; i < len(x); i++ {
if x[i] > 0 {
n_ele++
}
}
n_ele += 2
c_x := make([]C.struct_feature_node, n_ele)
j := 0
for i := 0; i < len(x); i++ {
if x[i] > 0 {
c_x[j].index = C.int(i + 1)
c_x[j].value = C.double(x[i])
j++
}
}
if bias > 0 {
c_x[j].index = C.int(0)
c_x[j].value = C.double(0)
j++
}
c_x[j].index = C.int(-1)
return &c_x[0]
}
func convert_features(X [][]float64, bias float64) **C.struct_feature_node {
n_samples := len(X)
n_elements := 0
for i := 0; i < n_samples; i++ {
for j := 0; j < len(X[i]); j++ {
if X[i][j] != 0.0 {
n_elements++
}
n_elements++ //for bias
}
}
x_space := make([]C.struct_feature_node, n_elements+n_samples)
cursor := 0
x := make([]*C.struct_feature_node, n_samples)
var c_x **C.struct_feature_node
for i := 0; i < n_samples; i++ {
x[i] = &x_space[cursor]
for j := 0; j < len(X[i]); j++ {
if X[i][j] != 0.0 {
x_space[cursor].index = C.int(j + 1)
x_space[cursor].value = C.double(X[i][j])
cursor++
}
if bias > 0 {
x_space[cursor].index = C.int(0)
x_space[cursor].value = C.double(bias)
cursor++
}
}
x_space[cursor].index = C.int(-1)
cursor++
}
c_x = &x[0]
return c_x
}