Confusion Matrix ValueError: Classification metrics can't handle a mix of binary and continuous targets

Question:

I’m currently trying to make a confusion matrix for my neural network model, but keep getting this error:

ValueError: Classification metrics can't handle a mix of binary and continuous targets.

I have a peptide dataset that I’m using with 100 positive and 100 negative examples, and the labels are 1s and 0s. I’ve converted each peptide into a Word2Vec embedding that was put into a ML model and trained.

This is my code:

pos = "/content/drive/MyDrive/pepfun/Training_format_pos (1).txt"
neg = "/content/drive/MyDrive/pepfun/Training_format_neg.txt"

# pos sequences extract into list
f = open(pos, 'r')
file_contents = f.read()
data = file_contents
f.close()

newdatapos = data.splitlines()
print(newdatapos)

# neg sequences extract into list
f2 = open(neg, 'r')
file_contents2 = f2.read()
data2 = file_contents2
f2.close()

newdataneg = data2.splitlines()
print(newdataneg)

!pip install rdkit-pypi
import rdkit
from rdkit import Chem

# set up embeddings
import nltk
from gensim.models import Word2Vec
import multiprocessing
EMB_DIM = 4

# embeddings pos
w2vpos = Word2Vec([newdatapos], size=EMB_DIM, min_count=1)
sequez = "VVYPWTQRF"
w2vpos[sequez].shape
words=list(w2vpos.wv.vocab)
vectors = []
for word in words:
  vectors.append(w2vpos[word].tolist())
print(len(vectors))
print(vectors[1])
data = np.array(vectors)

# embeddings neg
w2vneg = Word2Vec([newdataneg], size=EMB_DIM, min_count=1)
sequen = "GIGKFLHSAGKFGKAFLGEVMKS"
w2vneg[sequen].shape
wordsneg = list(w2vneg.wv.vocab)
vectorsneg = []
for word in wordsneg:
  vectorsneg.append(w2vneg[word].tolist())
allvectors = vectorsneg + vectors
print(len(allvectors))
arrayvectors = np.array(allvectors)

labels = []
for i in range (100):
  labels.append(1)
print(labels)
for i in range (100):
  labels.append(0)
print(labels)
print(len(labels))


import seaborn as sns
!pip install keras
import keras
from pylab import rcParams
import matplotlib.pyplot as plt
from matplotlib import rc
from sklearn.model_selection import train_test_split
from sklearn.metrics import confusion_matrix, classification_report
from sklearn.utils import shuffle
import numpy as np
import pandas as pd
import torch
import torch.nn as nn
import torch.optim as optim
from torch.utils.data import Dataset, DataLoader
from sklearn.preprocessing import StandardScaler
!pip install tensorflow==2.7.0
import tensorflow as tf
from keras import metrics  
from keras.models import Sequential
from keras.layers import Dense
from keras.layers import Conv3D, Flatten, Dropout


import sklearn
a = sklearn.utils.shuffle(arrayvectors, random_state=1)
b = sklearn.utils.shuffle(labels, random_state=1)
dfa = pd.DataFrame(a, columns=None)
dfb = pd.DataFrame(b, columns=None)
X = dfa.iloc[:]
y = dfb.iloc[:]

X_train, X_test, y_train, y_test = train_test_split(X,y,test_size=0.2, random_state=300)
X_train = np.asarray(X_train)
X_test = np.asarray(X_test)
y_train = np.asarray(y_train)
y_test = np.asarray(y_test)
y_train = y_train.astype(np.float32)
y_test = y_test.astype(np.float32)

# train data & test data tensor conversion

class trainData(Dataset):
    
    def __init__(self, X_data, y_data):
        self.X_data = X_data
        self.y_data = y_data
        
    def __getitem__(self, index):
        return self.X_data[index], self.y_data[index]
        
    def __len__ (self):
        return len(self.X_data)


train_data = trainData(torch.FloatTensor(X_train), 
                       torch.FloatTensor(y_train))
## test data    
class testData(Dataset):
    
    def __init__(self, X_data):
        self.X_data = X_data
        
    def __getitem__(self, index):
        return self.X_data[index]
        
    def __len__ (self):
        return len(self.X_data)
    

test_data = testData(torch.FloatTensor(X_test))

train_loader = DataLoader(train_data, batch_size=BATCH_SIZE, shuffle=True)
test_loader = DataLoader(test_data, batch_size=1)

# make model
model = Sequential()
model.add(Dense(64, activation='relu', input_shape=(4,)))
model.add(Dropout(0.1))
model.add(Dense(32, activation='relu'))
model.add(Dropout(0.1))
model.add(Dense(16, input_dim=1, activation='relu'))
model.add(Dropout(0.1))
model.add(Dense(12,activation='relu'))
model.add(Dropout(0.1))
model.add(Dense(1,activation='sigmoid'))
model.summary()

model.compile(loss='binary_crossentropy',optimizer='RMSprop', metrics=['accuracy','AUC'])

history = model.fit(X_train, y_train, epochs=2000,batch_size=64, validation_data = (X_test, y_test), validation_batch_size=64)


from sklearn.metrics import confusion_matrix, classification_report
print(y_pred.round)
print(classification_report(y_test,y_pred))

I’ve tried printing my y_pred value to see the problem. This is what I get:

[[6.0671896e-01]
 [9.9999785e-01]
 [1.6576621e-01]
 [9.9999899e-01]
 [5.6016445e-04]
 [2.4935007e-02]
 [4.4204036e-11]
 [2.8884350e-11]
 [6.3217885e-05]
 [4.7181606e-02]
 [9.9742711e-03]
 [1.0780278e-01]
 [7.0868194e-01]
 [2.0298421e-02]
 [9.5819527e-01]
 [1.4784497e-01]
 [1.7605269e-01]
 [9.9643111e-01]
 [4.7657710e-01]
 [9.9991858e-01]
 [4.5830309e-03]
 [6.5091753e-01]
 [3.8710403e-01]
 [2.4756461e-02]
 [1.1719930e-01]
 [6.4381957e-03]
 [7.1598434e-01]
 [1.5749395e-02]
 [6.8473631e-01]
 [9.5499575e-01]
 [2.2420317e-02]
 [9.9999177e-01]
 [6.9633877e-01]
 [9.2811453e-01]
 [1.8373668e-01]
 [2.9298562e-07]
 [1.1250973e-03]
 [4.3785056e-01]
 [9.6832716e-01]
 [8.6754566e-01]]

It’s not 1s and 0s. I believe there’s a problem there as well, but I’m not sure.

Asked By: Ash Roy

||

Answers:

The model outputs the predicted probabilities, you need to transform them back to class labels before calculating the classification metrics, see below.

import numpy as np
import tensorflow as tf
from tensorflow.keras.models import Sequential
from tensorflow.keras.layers import Dense, Dropout
from sklearn.datasets import make_classification
from sklearn.model_selection import train_test_split
from sklearn.metrics import confusion_matrix, classification_report
tf.random.set_seed(0)

# generate the data
X, y = make_classification(n_classes=2, n_features=4, n_informative=4, n_redundant=0, random_state=42)

# split the data
X_train, X_test, y_train, y_test = train_test_split(X, y, random_state=42)

# build the model
model = Sequential()
model.add(Dense(64, activation='relu', input_shape=(4,)))
model.add(Dropout(0.1))
model.add(Dense(32, activation='relu'))
model.add(Dropout(0.1))
model.add(Dense(16, input_dim=1, activation='relu'))
model.add(Dropout(0.1))
model.add(Dense(12, activation='relu'))
model.add(Dropout(0.1))
model.add(Dense(1, activation='sigmoid'))

# fit the model
model.compile(loss='binary_crossentropy', optimizer='RMSprop', metrics=['accuracy', 'AUC'])
model.fit(X_train, y_train, epochs=100, batch_size=64, validation_data=(X_test, y_test), validation_batch_size=64, verbose=0)

# extract the predicted probabilities
p_pred = model.predict(X_test)
p_pred = p_pred.flatten()
print(p_pred.round(2))
# [1. 0.01 0.91 0.87 0.06 0.95 0.24 0.58 0.78 ...

# extract the predicted class labels
y_pred = np.where(p_pred > 0.5, 1, 0)
print(y_pred)
# [1 0 1 1 0 1 0 1 1 0 0 0 0 1 1 0 1 0 0 0 0 ...

print(confusion_matrix(y_test, y_pred))
# [[13  1]
#  [ 2  9]]

print(classification_report(y_test, y_pred))
#               precision    recall  f1-score   support
#            0       0.87      0.93      0.90        14
#            1       0.90      0.82      0.86        11
#     accuracy                           0.88        25
#    macro avg       0.88      0.87      0.88        25
# weighted avg       0.88      0.88      0.88        25
Answered By: Flavia Giammarino