casa-mp-base

#!/usr/bin/env python

#This tool allow users to plot SVM-prob ROC curve from data

from svmutil import *

from sys import argv, platform

from os import path, popen

from random import randrange , seed

from operator import itemgetter

from time import sleep

​

#search path for gnuplot executable 

#be careful on using windows LONG filename, surround it with double quotes.

#and leading 'r' to make it raw string, otherwise, repeat \\.

gnuplot_exe_list = [r'"C:\Program Files\gnuplot\pgnuplot.exe"', "/usr/bin/gnuplot","/usr/local/bin/gnuplot"]

​

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def get_pos_deci(train_y, train_x, test_y, test_x, param):

    model = svm_train(train_y, train_x, param)

    #predict and grab decision value, assure deci>0 for label+,

    #the positive descision value = val[0]*labels[0]

    labels = model.get_labels()

    py, evals, deci = svm_predict(test_y, test_x, model)

    deci = [labels[0]*val[0] for val in deci]

    return deci,model

​

#get_cv_deci(prob_y[], prob_x[], svm_parameter param, nr_fold)

#input raw attributes, labels, param, cv_fold in decision value building

#output list of decision value, remember to seed(0)

def get_cv_deci(prob_y, prob_x, param, nr_fold):

    if nr_fold == 1 or nr_fold==0:

        deci,model = get_pos_deci(prob_y, prob_x, prob_y, prob_x, param)

        return deci

    deci, model = [], []

    prob_l = len(prob_y)

​

    #random permutation by swapping i and j instance

    for i in range(prob_l):

        j = randrange(i,prob_l)

        prob_x[i], prob_x[j] = prob_x[j], prob_x[i]

        prob_y[i], prob_y[j] = prob_y[j], prob_y[i]

​

    #cross training : folding

    for i in range(nr_fold):

        begin = i * prob_l // nr_fold

        end = (i + 1) * prob_l // nr_fold

        train_x = prob_x[:begin] + prob_x[end:]

        train_y = prob_y[:begin] + prob_y[end:]

        test_x = prob_x[begin:end]

        test_y = prob_y[begin:end]

        subdeci, submdel = get_pos_deci(train_y, train_x, test_y, test_x, param)

        deci += subdeci

    return deci

​

#a simple gnuplot object

class gnuplot:

    def __init__(self, term='onscreen'):

        # -persists leave plot window on screen after gnuplot terminates

        if platform == 'win32':

            cmdline = gnuplot_exe

            self.__dict__['screen_term'] = 'windows'

        else:

            cmdline = gnuplot_exe + ' -persist'

            self.__dict__['screen_term'] = 'x11'

        self.__dict__['iface'] = popen(cmdline,'w')