I have trained a classifier and I now want to pass any single image through.
I'm using the keras library with Tensorflow as the backend.
I'm getting an error I can't seem to get past
img_path = '/path/to/my/image.jpg'
import numpy as np
from keras.preprocessing import image
x = image.load_img(img_path, target_size=(250, 250))
x = image.img_to_array(x)
x = np.expand_dims(x, axis=0)
preds = model.predict(x)
Do I need to reshape my data to have None as the first dimension? I'm confused why Tensorflow would expect None as the first dimension?
Error when checking : expected convolution2d_input_1 to have shape (None, 250, 250, 3) but got array with shape (1, 3, 250, 250)
I'm wondering if there has been an issue with the architecture of my trained model?
edit: if i call model.summary() give convolution2d_input_1 as...
Edit: I did play around with the suggestion below but used numpy to transpose instead of tf - still seem to be hitting the same issue!
None matches any number. Usually, when you pass some data to a model, it is expected that you pass tensor of dimensions: None x data_size, meaning the first dimension is any dimension and denotes batch size. In your case, the problem is that you pass 250 x 250 x 3, and it is expected 3 x 250 x 250. Try:
x = image.load_img(img_path, target_size=(250, 250))
x_trans = tf.transpose(x, perm=[2, 0, 1])
x_expanded = np.expand_dims(x_trans, axis=0)
preds = model.predict(x_expanded)
Ok so using feedback rom Sygi i think i have half solved it,
The error was actually telling me i needed to pass in my dimensions as [1, 250, 250, 3] so that was an easy fix; i must say im not sure why TF is expecting the dimensions in this order as looking at the docs it doesnt seem right so more research required here.
Moving ahead im not sure transpose is the way to go as if i use a different input image the dimensions may not be in the same order meaning the transpose doesnt work properly,
Instead of transpose I'm probably trying to t call x_reshape = img.reshape((1, 250, 250, 3)) depending on what i find out about dimension order in reshaping for TS
thanks for the hints Sygi :)
Related
I want to use the Crossentropyloss of pytorch but somehow my code only works with batchsize 2, so i am asuming there is something wrong with the shapes of target and output.
I get following error:
Value Error: Expected target size (50, 2), got torch.Size([50, 3])
My targetsize is (N=50,batchsize=3) and the output of my model is (N=50, batchsize=3, number of classes =2). Before the output layer my shape is (N=50,batchsize=3,dimensions=64).
How do i need to change the shapes so that the Crossentropyloss works?
Without further information about your model, here's what I would do. You have a many-to-many RNN which outputs (seq_len, batch_size, nb_classes) and the target is (seq_len, seq_len). The nn.CrossEntropyLoss module can take additional dimensions (batch_size, nb_classes, d1â, d2â, ..., dKâ) as an input.
You could make it work by permuting the axes, such that the outputted tensor is of shape (batch_size, nb_classes, seq_len). This should make it happen:
output = output.permute(0, 2, 1)
Additionally, your target will also have to change to be (batch_size, seq_len):
target = target.permute(1, 0)
I am implementing a custom connection between two different keras layers. The neural network begins something like below:
model = tf.keras.Sequential()
c1 = model.add(Conv2D(6, kernel_size=[5,5], strides=(stride,stride), padding="valid", input_shape=(32,32,1),
activation = 'tanh'))
s2 = model.add(AveragePooling2D(pool_size=2, strides=2, padding='valid'))
Now, the output of s2 has a size of 14*14*6
Here, I want to apply my custom connection to convolution layer c3 which has an output size of 10*10*16 (that is, 16 filters need to be applied on s2 of size 14*14*6 and get an output of 10*10*16). For this, I need to use kernal_size = 5*5, filers=16, stride = 1, and padding=valid.
However, all the 6 feature maps (of s2) are not connected to 16 feature maps of (c3). The connections are explained as given here.
For example (the explanation of given link above), to build your first feature map of C3, you convolve 3 of your input maps (of s2 of size 14*14*6) with 5x5 filters, which gives you 3 10x10 maps that are summed up to give your first feature map, which is then of size 10x10.
I read somewhere that, we need to use Functional API to build this.
But, I am not sure, how to proceed further. Can someone help on implementing this.
My initial approach of implementing this is as follows:
from keras.models import Model
from keras.layers import Conv2D, Input, Concatenate, Lambda, Add
inputTensor = Input(shape=(14, 14,6))
stride =1
group0_a = Lambda(lambda x: x[:,:,0])(inputTensor)
group0_b = Lambda(lambda x: x[:,:,1])(inputTensor)
group0_c = Lambda(lambda x: x[:,:,2])(inputTensor) # Take 0,1,2 feature map of s2
conv_group0_a = Conv2D(1, kernel_size=[5,5], strides=(stride,stride), padding="valid", activation = 'tanh')(group0_a)
conv_group0_b = Conv2D(1, kernel_size=[5,5], strides=(stride,stride), padding="valid", activation = 'tanh')(group0_b)
conv_group0_c = Conv2D(1, kernel_size=[5,5], strides=(stride,stride), padding="valid", activation = 'tanh')(group0_c) #Applying convolution on each of 0, 1, 2 feature maps of s2 with distinct kernals
added_0 = Add()([conv_group0_a, conv_group0_b, conv_group0_c]) #adding all the three to get one of the 10*10*16
#Repeat this for 16 neurons of c3 and then finally
output_layer = Concatenate()([]) #concatenate them
Mymodel = Model(inputTensor,output_layer)
I want to know, if my approach is correct (I know it is not because I am getting too many errors). So, I need help in recreating the custom connection as explained above. Any help is appreciated.
the above code is correct, the only change I made is group0_a = Lambda(lambda x: x[:,:,0:1])(inputTensor), that is instead of passing x as x[:,:,0] I passed it as x[:,:,0:1]
I am trying to create a list based on my neural network outputs and use it in Tensorflow as a loss function.
Assume that results is list of size [1, batch_size] that is output by a neural network. I check to see whether the first value of this list is in a specific range passed in as a placeholder called valid_range, and if it is add 1 to a list. If it is not, add -1. The goal is to make all predictions of the network in the range, so the correct predictions is a tensor of all 1, which I call correct_predictions.
values_list = []
for j in range(batch_size):
a = results[0, j] >= valid_range[0]
b = result[0, j] <= valid_range[1]
c = tf.logical_and(a, b)
if (c == 1):
values_list.append(1)
else:
values_list.append(-1.)
values_list_tensor = tf.convert_to_tensor(values_list)
correct_predictions = tf.ones([batch_size, ], tf.float32)
Now, I want to use this as a loss function in my network, so that I can force all the predictions to be in the specified range. I try to train like this:
loss = tf.reduce_mean(tf.squared_difference(values_list_tensor, correct_predictions))
optimizer = tf.train.AdamOptimizer(learning_rate=learning_rate)
gradients, variables = zip(*optimizer.compute_gradients(loss))
gradients, _ = tf.clip_by_global_norm(gradients, gradient_clip_threshold)
optimize = optimizer.apply_gradients(zip(gradients, variables))
This, however, has a problem and throws an error on the last optimize line, saying:
ValueError: No gradients provided for any variable: ['<tensorflow.python.training.optimizer._RefVariableProcessor object at 0x7f0245d4afd0>',
'<tensorflow.python.training.optimizer._RefVariableProcessor object at 0x7f0245d66050>'
...
I tried to debug this in Tensorboard, and I notice that the list I am creating does not appear in the graph, so basically the x part of the loss function is not part of the network itself. Is there some way to accurately create a list based on the predictions of a neural network and use it in the loss function in Tensorflow to train the network?
Please help, I have been stuck on this for a few days now.
Edit:
Following what was suggested in the comments, I decided to use a l2 loss function, multiplying it by the binary vector I had from before values_list_tensor. The binary vector now has values 1 and 0 instead of 1 and -1. This way when the prediction is in the range the loss is 0, else it is the normal l2 loss. As I am unable to see the values of the tensors, I am not sure if this is correct. However, I can view the final loss and it is always 0, so something is wrong here. I am unsure if the multiplication is being done correctly and if values_list_tensor is calculated accurately? Can someone help and tell me what could be wrong?
loss = tf.reduce_mean(tf.nn.l2_loss(tf.matmul(tf.transpose(tf.expand_dims(values_list_tensor, 1)), tf.expand_dims(result[0, :], 1))))
Thanks
To answer the question in the comment. One way to write a piece-wise function is using tf.cond. For example, here is a function that returns 0 in [-1, 1] and x everywhere else:
sess = tf.InteractiveSession()
x = tf.placeholder(tf.float32)
y = tf.cond(tf.logical_or(tf.greater(x, 1.0), tf.less(x, -1.0)), lambda : x, lambda : 0.0)
y.eval({x: 1.5}) # prints 1.5
y.eval({x: 0.5}) # prints 0.0
I need to utilize TensorFlow for a project to classify items based on their attributes to a certain class (either 1, 2, or 3).
Only problem is almost every TF tutorial or example I find online is about image recognition or text classification. I can't find anything about classification based on numbers. I guess what I'm asking for is where to get started. If anyone knows of a relevant example, or if I'm just thinking about this completely wrong.
We are given the 13 attributes for each item, and need to use the TF neural network to classify each item correctly (or mark the margin of error). But nothing online is showing me even how to start with this kind of dataset.
Example of dataset: (first value is class, other values are attributes)
2, 11.84, 2.89, 2.23, 18, 112, 1.72, 1.32, 0.43, 0.95, 2.65, 0.96, 2.52, 500
3, 13.69, 3.26, 2.54, 20, 107, 1.83, 0.56, 0.5, 0.8, 5.88, 0.96, 1.82, 680
3, 13.84, 4.12, 2.38, 19.5, 89, 1.8, 0.83, 0.48, 1.56, 9.01, 0.57, 1.64, 480
2, 11.56, 2.05, 3.23, 28.5, 119, 3.18, 5.08, 0.47, 1.87, 6, 0.93, 3.69, 465
1, 14.06, 1.63, 2.28, 16, 126, 3, 3.17, 0.24, 2.1, 5.65, 1.09, 3.71, 780
Suppose you have the data in a file, data.txt. You can use Numpy to read this:
import numpy as np
xy = np.loadtxt('data.txt', unpack=True, dtype='float32')
x_data = xy[1:]
y_data = xy[0];
More information: http://docs.scipy.org/doc/numpy-1.10.0/reference/generated/numpy.loadtxt.html
Perhaps, you may need 'np.transpose' depends on the shape of your weights and operations.
x_data = np.transpose(xy[1:])
Then, use 'placeholders' and 'feed_dict' to train/test your model:
X = tf.placeholder("float", ...
Y = tf.placeholder("float", ...
....
with tf.Session() as sess:
....
sess.run(optimizer, feed_dict={X:x_data, Y:y_data})
for this kind problem TensorFlow have an in depth tutorial here
or in toward data science here
if your looking for videos to start i think sentdex's tutorials on the titanic data-set
is what your looking for although he is using k means to do the classification
(actually I think his entire deep learning/machine learning playlist is great to start with)
you can find it here
otherwise if your looking for basic how to start
first prepossessing:
try first separating the data into class labels and inputs (pandas lib should be able to help you with this)
make your class labels into a one-hot array
than normalize the data:
it looks like your different data attributes have wildly different ranges, make sure to get them all in the same range between 0 and 1
build your model:
a simple fully connected net should do the trick
remember to make the output layer the same size as the number of classes you have
use an argmax function on the output of the finale layer to decide which class the model thinks is the proper classification
It seems that variable.shape would notify me that
AttributeError: 'SharedVariable' object has no attribute 'shape'
while theano.tensor.shape(variable) will return me a shape.0
I am really confused why can't I get a shape information on that? The same problem occurs when I want to get the shape information of a symbolic variable. It is just so weird.
x = T.matrix('x') # the data is presented as rasterized images
y = T.ivector('y') # the labels are presented as 1D vector of
# [int] labels
layer0_input = x.reshape((batch_size, 1, 28, 28))
In the example above, the x (symbolic variable) has been reshaped to some shape, if would not make sense to me if I can't retrieve its shape information while could still assigning it new shape.
The first error is probably due to the fact that you tried to evaluate the shape property on the data type SharedVariable, not on an actual shared variable.
Otherwise, obtaining shape.0 is completely normal: This is a symbolic expression representing the shape, which is a priori unknown. As soon as you evaluate with data, you will see the shape:
import theano
import theano.tensor as T
import numpy as np
s = theano.shared(np.arange(2 * 3 * 5).reshape(2, 3, 5))
print(s.shape) # gives you shape.0
print(s.shape.eval()) # gives you an array containing 2, 3, 5
a = T.tensor3()
print(a.shape) # gives you shape.0
print(a.shape.eval({a: np.arange(2 * 3 * 5).reshape(2, 3, 5).astype(theano.config.floatX)})) # gives 2, 3, 5