Keras : KeyError: 'acc' , during plotting - python-3.x

Question

i'm trying to visualize the Training plot of my Model , and i get this Error :
Traceback (most recent call last):
File "train.py", line 120, in <module>
plt.plot(H.history['acc'])
KeyError: 'acc'
& here's the Full Code :
# set the matplotlib backend so figures can be saved in the background
import matplotlib
matplotlib.use("Agg")
# import the necessary packages
from pyimagesearch.resnet import ResNet
from sklearn.preprocessing import LabelEncoder
from sklearn.model_selection import train_test_split
from sklearn.metrics import classification_report
from keras.preprocessing.image import ImageDataGenerator
from keras.optimizers import SGD
from keras.utils import np_utils
from imutils import paths
import matplotlib.pyplot as plt
import numpy as np
import argparse
import cv2
import os
# construct the argument parser and parse the arguments
ap = argparse.ArgumentParser()
ap.add_argument("-d", "--dataset", required=True,
help="path to input dataset")
ap.add_argument("-a", "--augment", type=int, default=-1,
help="whether or not 'on the fly' data augmentation should be used")
ap.add_argument("-p", "--plot", type=str, default="plot.png",
help="path to output loss/accuracy plot")
args = vars(ap.parse_args())
# initialize the initial learning rate, batch size, and number of
# epochs to train for
INIT_LR = 1e-1
BS = 8
EPOCHS = 50
# grab the list of images in our dataset directory, then initialize
# the list of data (i.e., images) and class images
print("[INFO] loading images...")
imagePaths = list(paths.list_images(args["dataset"]))
data = []
labels = []
# loop over the image paths
for imagePath in imagePaths:
# extract the class label from the filename, load the image, and
# resize it to be a fixed 64x64 pixels, ignoring aspect ratio
label = imagePath.split(os.path.sep)[-2]
image = cv2.imread(imagePath)
image = cv2.resize(image, (64, 64))
# update the data and labels lists, respectively
data.append(image)
labels.append(label)
# convert the data into a NumPy array, then preprocess it by scaling
# all pixel intensities to the range [0, 1]
data = np.array(data, dtype="float") / 255.0
# encode the labels (which are currently strings) as integers and then
# one-hot encode them
le = LabelEncoder()
labels = le.fit_transform(labels)
labels = np_utils.to_categorical(labels, 3)
# partition the data into training and testing splits using 75% of
# the data for training and the remaining 25% for testing
(trainX, testX, trainY, testY) = train_test_split(data, labels,
test_size=0.25, random_state=42)
# initialize an our data augmenter as an "empty" image data generator
aug = ImageDataGenerator()
# check to see if we are applying "on the fly" data augmentation, and
# if so, re-instantiate the object
if args["augment"] > 0:
print("[INFO] performing 'on the fly' data augmentation")
aug = ImageDataGenerator(
rotation_range=20,
zoom_range=0.15,
width_shift_range=0.2,
height_shift_range=0.2,
shear_range=0.15,
horizontal_flip=True,
fill_mode="nearest")
# initialize the optimizer and model
print("[INFO] compiling model...")
opt = SGD(lr=INIT_LR, momentum=0.9, decay=INIT_LR / EPOCHS)
model = ResNet.build(64, 64, 3, 2, (2, 3, 4),
(32, 64, 128, 256), reg=0.0001)
model.compile(loss="categorical_crossentropy", optimizer=opt,
metrics=["accuracy"])
# train the network
print("[INFO] training network for {} epochs...".format(EPOCHS))
H = model.fit_generator(
aug.flow(trainX, trainY, batch_size=BS),
validation_data=(testX, testY),
steps_per_epoch=len(trainX) // BS,
epochs=EPOCHS)
# evaluate the network
print("[INFO] evaluating network...")
predictions = model.predict(testX, batch_size=BS)
print(classification_report(testY.argmax(axis=1),
predictions.argmax(axis=1), target_names=le.classes_))
# plot the training loss and accuracy
N = np.arange(0, EPOCHS)
plt.style.use("ggplot")
plt.figure()
plt.plot(N, H.history["loss"], label="train_loss")
plt.plot(N, H.history['val_loss'], label="val_loss")
plt.plot(N, H.history['acc'], label="accuracy")
plt.plot(N, H.history['val_acc'], label="val_acc")
plt.title("Training Loss and Accuracy on Dataset")
plt.xlabel("Epoch #")
plt.ylabel("Loss/Accuracy")
plt.legend(loc="lower left")
plt.savefig(args["plot"])
So, this code , is originally from the blog Pyimagesearch , on data augmentation , so , i decided to give it a try , the original "pipeline" was meant for a binary classification , so , since i was intrested in a mutli-class "task" , i brought some changes.
but the plotting part of the code , seems correct to me , i cheked on multiple posts here on Stack , checked the keras documentation , and nothing , i do not understand , why it dose not work !!!!
any suggestion would be much appreciated .
thank you.

Answer 1

Have you tried H.history['accuracy']? Since you compiled using 'accuracy' it will probably have the same string.
Now you can always inspect what you've got:
for key in H.history.keys():
print(key)
You will see what is logged there