I am new to programming and used Google OR-tools to create my VRP model. In my current model, I have included a general time window and capacity constraint per vehicle, creating a capacitated vehicle routing problem with time windows. I followed the OR-tools guides which contains a maximum travel duration for each vehicle.
However, I want to include a maximum travel duration for the sum of all routes, whereas the maximum travel duration for each vehicle does not matter (so I set it to 100.000). Accorddingly, I want to create something in the model/solution printer that tells me which amount of addresses could not be visited due to the constraint on the maximum travel duration for the sum of all routes. From the examples I have seen I think it would be kind of easy, but my knowledge on programming is fairly limited, so my attempts had no succes. Can anyone help me?
import pandas as pd
import openpyxl
import numpy as np
import math
from random import sample
from ortools.constraint_solver import routing_enums_pb2
from ortools.constraint_solver import pywrapcp
from scipy.spatial.distance import squareform, pdist
from haversine import haversine
#STEP - create data
# import/read excel file
data = pd.read_excel(r'C:\Users\Jean-Paul\Documents\Thesis\OR TOOLS\Data.xlsx', engine = 'openpyxl')
df = pd.DataFrame(data, columns= ['number','lat','lng']) # create dataframe with 10805 addresses + address of the depot
#print (df)
# randomly sample X addresses from the dataframe and their corresponding number/latitude/longtitude
df_sample = df.sample(n=100)
#print (df_data)
# read first row of the excel file (= coordinates of the depot)
df_depot = pd.DataFrame(data, columns= ['number','lat','lng']).iloc[0:1]
#print (df_depot)
# combine dataframe of depot and sample into one dataframe
df_data = pd.concat([df_depot, df_sample], ignore_index=True, sort=False)
#print (df_data)
#STEP - create distance matrix data
# determine distance between latitude and longtitude
df_data.set_index('number', inplace=True)
matrix_distance = pd.DataFrame(squareform(pdist(df_data, metric=haversine)), index=df_data.index, columns=df_data.index)
matrix_list = np.array(matrix_distance)
#print (matrix_distance) # create table of distances between addresses including headers
#print (matrix_list) # converting table to list of lists and exclude headers
#STEP - create time matrix data
travel_time = matrix_list / 15 * 60 # divide distance by travel speed 20 km/h and multiply by 60 minutes
#print (travel_time) # converting distance matrix to travel time matrix
#STEP - create time window data
# create list for each sample - couriers have to visit this address within 0-X minutes of time using a list of lists
window_range = []
for i in range(len(df_data)):
list = [0, 240]
window_range.append(list) # create list of list with a time window range for each address
#print (window_range)
#STEP - create demand data
# create list for each sample - all addresses demand 1 parcel except the depot
demand_range = []
for i in range(len(df_data.iloc[0:1])):
list = 0
demand_range.append(list)
for j in range(len(df_data.iloc[1:])):
list2 = 1
demand_range.append(list2)
#print (demand_range)
#STEP - create fleet size data # amount of vehicles in the fleet
fleet_size = 6
#print (fleet_size)
#STEP - create capacity data for each vehicle
fleet_capacity = []
for i in range(fleet_size): # capacity per vehicle
list = 20
fleet_capacity.append(list)
#print (fleet_capacity)
#STEP - create data model that stores all data for the problem
def create_data_model():
data = {}
data['time_matrix'] = travel_time
data['time_windows'] = window_range
data['num_vehicles'] = fleet_size
data['depot'] = 0 # index of the depot
data['demands'] = demand_range
data['vehicle_capacities'] = fleet_capacity
return data
#STEP - creating the solution printer
def print_solution(data, manager, routing, solution):
"""Prints solution on console."""
print(f'Objective: {solution.ObjectiveValue()}')
time_dimension = routing.GetDimensionOrDie('Time')
total_time = 0
for vehicle_id in range(data['num_vehicles']):
index = routing.Start(vehicle_id)
plan_output = 'Route for vehicle {}:\n'.format(vehicle_id)
while not routing.IsEnd(index):
time_var = time_dimension.CumulVar(index)
plan_output += '{0} Time({1},{2}) -> '.format(
manager.IndexToNode(index), solution.Min(time_var),
solution.Max(time_var))
index = solution.Value(routing.NextVar(index))
time_var = time_dimension.CumulVar(index)
plan_output += '{0} Time({1},{2})\n'.format(manager.IndexToNode(index),
solution.Min(time_var),
solution.Max(time_var))
plan_output += 'Time of the route: {}min\n'.format(
solution.Min(time_var))
print(plan_output)
total_time += solution.Min(time_var)
print('Total time of all routes: {}min'.format(total_time))
#STEP - create the VRP solver
def main():
# instantiate the data problem
data = create_data_model()
# create the routing index manager
manager = pywrapcp.RoutingIndexManager(len(data['time_matrix']),
data['num_vehicles'], data['depot'])
# create routing model
routing = pywrapcp.RoutingModel(manager)
#STEP - create demand callback and dimension for capacity
# create and register a transit callback
def demand_callback(from_index):
"""Returns the demand of the node."""
# convert from routing variable Index to demands NodeIndex
from_node = manager.IndexToNode(from_index)
return data['demands'][from_node]
demand_callback_index = routing.RegisterUnaryTransitCallback(
demand_callback)
routing.AddDimensionWithVehicleCapacity(
demand_callback_index,
0, # null capacity slack
data['vehicle_capacities'], # vehicle maximum capacities
True, # start cumul to zero
'Capacity')
#STEP - create time callback
# create and register a transit callback
def time_callback(from_index, to_index):
"""Returns the travel time between the two nodes."""
# convert from routing variable Index to time matrix NodeIndex
from_node = manager.IndexToNode(from_index)
to_node = manager.IndexToNode(to_index)
return data['time_matrix'][from_node][to_node]
transit_callback_index = routing.RegisterTransitCallback(time_callback)
# define cost of each Arc (costs in terms of travel time)
routing.SetArcCostEvaluatorOfAllVehicles(transit_callback_index)
# STEP - create a dimension for the travel time (TIMEWINDOW) - dimension keeps track of quantities that accumulate over a vehicles route
# add time windows constraint
time = 'Time'
routing.AddDimension(
transit_callback_index,
2, # allow waiting time (does not have an influence in this model)
100000, # maximum total route lenght in minutes per vehicle (does not have an influence because of capacity constraint)
False, # do not force start cumul to zero
time)
time_dimension = routing.GetDimensionOrDie(time)
# add time window constraints for each location except depot
for location_idx, time_window in enumerate(data['time_windows']):
if location_idx == data['depot']:
continue
index = manager.NodeToIndex(location_idx)
time_dimension.CumulVar(index).SetRange(time_window[0], time_window[1])
# add time window constraint for each vehicle start node
depot_idx = data['depot']
for vehicle_id in range(data['num_vehicles']):
index = routing.Start(vehicle_id)
time_dimension.CumulVar(index).SetRange(
data['time_windows'][depot_idx][0],
data['time_windows'][depot_idx][1])
#STEP - instantiate route start and end times to produce feasible times
for i in range(data['num_vehicles']):
routing.AddVariableMinimizedByFinalizer(
time_dimension.CumulVar(routing.Start(i)))
routing.AddVariableMinimizedByFinalizer(
time_dimension.CumulVar(routing.End(i)))
#STEP - setting default search parameters and a heuristic method for finding the first solution
search_parameters = pywrapcp.DefaultRoutingSearchParameters()
search_parameters.first_solution_strategy = (
routing_enums_pb2.FirstSolutionStrategy.PATH_CHEAPEST_ARC)
#STEP - solve the problem with the serach parameters and print solution
solution = routing.SolveWithParameters(search_parameters)
if solution:
print_solution(data, manager, routing, solution)
if __name__ == '__main__':
main()
See #Mizux's answer, going under-the-hood in the solver to make a summation cost over all vehicle route lengths:
https://stackoverflow.com/a/68756570/13773745
Related
I have a convolutional neural network. And I wanted to train it on images from the training set but first they should be wrapped with my function change(tensor, float) that takes in a tensor/image of the form [hight,width,3] and a float.
Batch size =4
loading data
trainset = torchvision.datasets.CIFAR10(root='./data', train=True,
download=True, transform=transform)
trainloader = torch.utils.data.DataLoader(trainset, batch_size=batch_size,
shuffle=True, num_workers=2)
Cnn architecture
for epoch in range(2): # loop over the dataset multiple times
running_loss = 0.0
for i, data in enumerate(trainloader, 0):
# get the inputs; data is a list of [inputs, labels]
inputs, labels = data
#size of inputs [4,3,32,32]
#size of labels [4]
inputs = change(inputs,0.1) <----------------------------
# zero the parameter gradients
optimizer.zero_grad()
# forward + backward + optimize
outputs = net(inputs) #[4, 10]
loss = criterion(outputs, labels)
loss.backward()
optimizer.step()
# print statistics
running_loss += loss.item()
if i % 2000 == 1999: # print every 2000 mini-batches
print(f'[{epoch + 1}, {i + 1:5d}] loss: {running_loss / 2000:.3f}')
running_loss = 0.0
print('Finished Training')
I am trying to apply the image function change but it gives an object error.
it there a quick way to fix it?
I am using a Julia function but it works completely fine with other objects. Error message:
JULIA: MethodError: no method matching copy(::PyObject)
Closest candidates are:
copy(!Matched::T) where T<:SHA.SHA3_CTX at /opt/julia-1.7.2/share/julia/stdlib/v1.7/SHA/src/types.jl:213
copy(!Matched::T) where T<:SHA.SHA2_CTX at /opt/julia-1.7.2/share/julia/stdlib/v1.7/SHA/src/types.jl:212
copy(!Matched::Number) at /opt/julia-1.7.2/share/julia/base/number.jl:113
I would recommend to put change function to transforms list, so you do data changes on transformation stage.
partial from functools will help you to fix number of arguments, like this:
from functools import partial
def change(input, float):
pass
# Use partial to fix number of params, such that change accepts only input
change_partial = partial(change, float=pass_float_value_here)
# Add change_partial to a list of transforms before or after converting to tensors
transforms = Compose([
RandomResizedCrop(img_size), # example
# Add change_partial here if it operates on PIL Image
change_partial,
ToTensor(), # convert to tensor
# Add change_partial here if it operates on torch tensors
change_partial,
])
I am trying to speed up the calculations from multiple operations that I am adding as columns in a pyspark data frame, when I found the sparkbyexamples article on performance tunning. I am considering how to use the cache and the spark.sql.shuffle.partitions, solutions.
Would cache be appropriate for a code that first joins multiple data
frames and then adds calculations over different windows?
What happens when reassigning the cached data frame (see bellow)?
Example:
df = dfA.join(dfB, on = ['key'], how ='left') # should I add .cache here?
w_u = Window.partitionBy('user')
w_m = Window.partitionBy(['user','month']).orderBy('month')\
.rangeBetween(Window.unboundedPreceding, Window.unboundedFollowing)
MLAB = ['val1','val2'] # example to indicate that I run similar operations multiple times
for mlab in MLAB:
percent_50 = F.expr('percentile_approx('+mlab+',0.5)')
df = df.withColumn(mlab+'_md', percent_50.over(w_u) # what happens with the cache when I reassing it
Afterwards I am adding additional operations that include aggregations, such as:
radius_df = (df
# number of visits per stop
.groupby('userId', 'locationId').agg(F.count(F.lit(1)).alias('n_i'),
F.first('locationLongitude').alias('locationLongitude'),
F.first('locationLatitude').alias('locationLatitude'))
#compute center of mass (lat/lon) per user
.withColumn('center_lon', F.avg(F.col('locationLongitude')).over(w))
.withColumn('center_lat', F.avg(F.col('locationLatitude')).over(w))
# compute total visits
.withColumn('N', F.sum(F.col('n_i')).over(w))
# compute (r_i - r_cm)
.withColumn('distance', distance(F.col('locationLatitude'), F.col('locationLongitude'), F.col('center_lat'), F.col('center_lon')))
# compute n_i(r_i - r_cm)^2 / N
.withColumn('distance2', F.col('n_i') * (F.col('distance') * F.col('distance')) / F.col('N'))
# compute sum(n_i(r_i - r_cm)^2)
.groupBy('userId').agg(F.sum(F.col('distance2')).alias('sum_dist2'))
# square root
.withColumn('radius_gyr', F.sqrt(F.col('sum_dist2')))
.select('userId','radius_gyr')
)
df_f = df.join(radius_df.dropDuplicates(), on='userId', how='left')
I am open to any suggestions on how to speed up the code. Many thanks.
I am training a VAE (using federated learning, but that is not so important) and wanted to keep the loss and train functions simple to exchange. The initial approach was to have a tf.function as loss function and a tf.function as train function as follows:
#tf.function
def kl_reconstruction_loss(model, model_input, beta):
x, y = model_input
mean, logvar = model.encode(x, y)
z = model.reparameterize(mean, logvar)
x_logit = model.decode(z, y)
cross_ent = tf.nn.sigmoid_cross_entropy_with_logits(logits=x_logit, labels=x)
reconstruction_loss = tf.reduce_mean(tf.reduce_sum(cross_ent, axis=[1, 2, 3]), axis=0)
kl_loss = tf.reduce_mean(0.5 * tf.reduce_sum(tf.exp(logvar) + tf.square(mean) - 1. - logvar, axis=-1), axis=0)
loss = reconstruction_loss + beta * kl_loss
return loss, kl_loss, reconstruction_loss
#tf.function
def train_fn(model: tf.keras.Model, batch, optimizer, kl_beta):
"""Trains the model on a single batch.
Args:
model: The VAE model.
batch: A batch of inputs [images, labels] for the vae.
optimizer: The optimizer to train the model.
beta: Weighting of KL loss
Returns:
The loss.
"""
def vae_loss():
"""Does the forward pass and computes losses for the generator."""
# N.B. The complete pass must be inside loss() for gradient tracing.
return kl_reconstruction_loss(model, batch, kl_beta)
with tf.GradientTape() as tape:
loss, kl_loss, rc_loss = vae_loss()
grads = tape.gradient(loss, model.trainable_variables)
grads_and_vars = zip(grads, model.trainable_variables)
optimizer.apply_gradients(grads_and_vars)
return loss
For my dataset this results in an epoch duration of approx. 25 seconds. However, since I have to call those functions directly in my code, I would have to enter different ones if I would want to try out different loss/train functions.
So, alternatively, I followed https://github.com/google-research/federated/tree/master/gans and wrapped the loss function in a class and the train function in another function. Now I have:
class VaeKlReconstructionLossFns(AbstractVaeLossFns):
#tf.function
def vae_loss(self, model, model_input, labels, global_round):
# KL Reconstruction loss
mean, logvar = model.encode(model_input, labels)
z = model.reparameterize(mean, logvar)
x_logit = model.decode(z, labels)
cross_ent = tf.nn.sigmoid_cross_entropy_with_logits(logits=x_logit, labels=model_input)
reconstruction_loss = tf.reduce_mean(tf.reduce_sum(cross_ent, axis=[1, 2, 3]), axis=0)
kl_loss = tf.reduce_mean(0.5 * tf.reduce_sum(tf.exp(logvar) + tf.square(mean) - 1. - logvar, axis=-1), axis=0)
loss = reconstruction_loss + self._get_beta(global_round) * kl_loss
if model.losses:
loss += tf.add_n(model.losses)
return loss, kl_loss, reconstruction_loss
def create_train_vae_fn(
vae_loss_fns: vae_losses.AbstractVaeLossFns,
vae_optimizer: tf.keras.optimizers.Optimizer):
"""Create a function that trains VAE, binding loss and optimizer.
Args:
vae_loss_fns: Instance of gan_losses.AbstractVAELossFns interface,
specifying the VAE training loss.
vae_optimizer: Optimizer for training the VAE.
Returns:
Function that executes one step of VAE training.
"""
# We check that the optimizer has not been used previously, which ensures
# that when it is bound the train fn isn't holding onto a different copy of
# the optimizer variables then the copy that is being exchanged b/w server and
# clients.
if vae_optimizer.variables():
raise ValueError(
'Expected vae_optimizer to not have been used previously, but '
'variables were already initialized.')
#tf.function
def train_vae_fn(model: tf.keras.Model,
model_inputs,
labels,
global_round,
new_optimizer_state=None):
"""Trains the model on a single batch.
Args:
model: The VAE model.
model_inputs: A batch of inputs (usually images) for the VAE.
labels: A batch of labels corresponding to the inputs.
global_round: The current glob al FL round for beta calculation
new_optimizer_state: A possible optimizer state to overwrite the current one with.
Returns:
The number of examples trained on.
The loss.
The updated optimizer state.
"""
def vae_loss():
"""Does the forward pass and computes losses for the generator."""
# N.B. The complete pass must be inside loss() for gradient tracing.
return vae_loss_fns.vae_loss(model, model_inputs, labels, global_round)
# Set optimizer vars
optimizer_state = get_optimizer_state(vae_optimizer)
if new_optimizer_state is not None:
# if optimizer is uninitialised, initialise vars
try:
tf.nest.assert_same_structure(optimizer_state, new_optimizer_state)
except ValueError:
initialize_optimizer_vars(vae_optimizer, model)
optimizer_state = get_optimizer_state(vae_optimizer)
tf.nest.assert_same_structure(optimizer_state, new_optimizer_state)
tf.nest.map_structure(lambda a, b: a.assign(b), optimizer_state, new_optimizer_state)
with tf.GradientTape() as tape:
loss, kl_loss, rc_loss = vae_loss()
grads = tape.gradient(loss, model.trainable_variables)
grads_and_vars = zip(grads, model.trainable_variables)
vae_optimizer.apply_gradients(grads_and_vars)
return tf.shape(model_inputs)[0], loss, optimizer_state
return train_vae_fn
This new formulation takes about 86 seconds per epoch.
I am struggling to understand why the second version performs so much worse than the first one. Does anyone have a good explanation for this?
Thanks in advance!
EDIT: My Tensorflow version is 2.5.0
After some research, I was able to predict the future value using the LSTM code below. I have also attached the Dmd1ahr.csv file in the github link that I am using.
https://github.com/ukeshchawal/hello-world/blob/master/Dmd1ahr.csv
As you all can see below, 90 data points are training sets and 91st to 100th are future value prediction.
However some of the questions that I still have are:
In order to predict these values I had to originally take more than hundred data sets (here, I have taken 500 data sets) which is not exactly what my primary goal is. Is there a way that given 500 data sets, it will predict the rest 10 or 20 out of sample data points? If yes, will you please write me a sample code where you can just take 500 data points from Dmd1ahr.csv file attached below and it will predict some future values (say 501 to 520) based on those 500 points?
The prediction are way off compared to the one who have in your blogs (definitely indicates for parameter tuning - I tried changing epochs, LSTM layers, Activation, optimizer). What other parameter tuning I can do to make it more robust?
Thank you'll in advance.
import numpy as np
import matplotlib.pyplot as plt
import pandas
# By twaking the architecture it could be made more robust
np.random.seed(7)
numOfSamples = 500
lengthTrain = 90
lengthValidation = 100
look_back = 1 # Can be set higher, in my experiments it made performance worse though
transientTime = 90 # Time to "burn in" time series
series = pandas.read_csv('Dmd1ahr.csv')
def generateTrainData(series, i, look_back):
return series[i:look_back+i+1]
trainX = np.stack([generateTrainData(series, i, look_back) for i in range(lengthTrain)])
testX = np.stack([generateTrainData(series, lengthTrain + i, look_back) for i in range(lengthValidation)])
trainX = trainX.reshape((lengthTrain,look_back+1,1))
testX = testX.reshape((lengthValidation, look_back + 1, 1))
trainY = trainX[:,1:,:]
trainX = trainX[:,:-1,:]
testY = testX[:,1:,:]
testX = testX[:,:-1,:]
############### Build Model ###############
import keras
from keras.models import Model
from keras import layers
from keras import regularizers
inputs = layers.Input(batch_shape=(1,look_back,1), name="main_input")
inputsAux = layers.Input(batch_shape=(1,look_back,1), name="aux_input")
# this layer makes the actual prediction, i.e. decides if and how much it goes up or down
x = layers.recurrent.LSTM(300,return_sequences=True, stateful=True)(inputs)
x = layers.recurrent.LSTM(200,return_sequences=True, stateful=True)(inputs)
x = layers.recurrent.LSTM(100,return_sequences=True, stateful=True)(inputs)
x = layers.recurrent.LSTM(50,return_sequences=True, stateful=True)(inputs)
x = layers.wrappers.TimeDistributed(layers.Dense(1, activation="linear",
kernel_regularizer=regularizers.l2(0.005),
activity_regularizer=regularizers.l1(0.005)))(x)
# auxillary input, the current input will be feed directly to the output
# this way the prediction from the step before will be used as a "base", and the Network just have to
# learn if it goes a little up or down
auxX = layers.wrappers.TimeDistributed(layers.Dense(1,
kernel_initializer=keras.initializers.Constant(value=1),
bias_initializer='zeros',
input_shape=(1,1), activation="linear", trainable=False
))(inputsAux)
outputs = layers.add([x, auxX], name="main_output")
model = Model(inputs=[inputs, inputsAux], outputs=outputs)
model.compile(optimizer='adam',
loss='mean_squared_error',
metrics=['mean_squared_error'])
#model.summary()
#model.fit({"main_input": trainX, "aux_input": trainX[look_back-1,look_back,:]},{"main_output": trainY}, epochs=4, batch_size=1, shuffle=False)
model.fit({"main_input": trainX, "aux_input": trainX[:,look_back-1,:].reshape(lengthTrain,1,1)},{"main_output": trainY}, epochs=100, batch_size=1, shuffle=False)
############### make predictions ###############
burnedInPredictions = np.zeros(transientTime)
testPredictions = np.zeros(len(testX))
# burn series in, here use first transitionTime number of samples from test data
for i in range(transientTime):
prediction = model.predict([np.array(testX[i, :, 0].reshape(1, look_back, 1)), np.array(testX[i, look_back - 1, 0].reshape(1, 1, 1))])
testPredictions[i] = prediction[0,0,0]
burnedInPredictions[:] = testPredictions[:transientTime]
# prediction, now dont use any previous data whatsoever anymore, network just has to run on its own output
for i in range(transientTime, len(testX)):
prediction = model.predict([prediction, prediction])
testPredictions[i] = prediction[0,0,0]
# for plotting reasons
testPredictions[:np.size(burnedInPredictions)-1] = np.nan
############### plot results ###############
#import matplotlib.pyplot as plt
plt.plot(testX[:, 0, 0])
plt.show()
plt.plot(burnedInPredictions, label = "training")
plt.plot(testPredictions, label = "prediction")
plt.legend()
plt.show()
I want to extract protein sequences and their corresponding secondary structure from any Protein Data bank, say RCSB. I just need short sequences and their secondary structure. Something like,
ATRWGUVT Helix
It is fine even if the sequences are long, but I want a tag at the end that denotes its secondary structure. Is there any programming tool or anything available for this.
As I've shown above I want only this much minimal information. How can I achieve this?
from Bio.PDB import *
from distutils import spawn
Extract sequence:
def get_seq(pdbfile):
p = PDBParser(PERMISSIVE=0)
structure = p.get_structure('test', pdbfile)
ppb = PPBuilder()
seq = ''
for pp in ppb.build_peptides(structure):
seq += pp.get_sequence()
return seq
Extract secondary structure with DSSP as explained earlier:
def get_secondary_struc(pdbfile):
# get secondary structure info for whole pdb.
if not spawn.find_executable("dssp"):
sys.stderr.write('dssp executable needs to be in folder')
sys.exit(1)
p = PDBParser(PERMISSIVE=0)
ppb = PPBuilder()
structure = p.get_structure('test', pdbfile)
model = structure[0]
dssp = DSSP(model, pdbfile)
count = 0
sec = ''
for residue in model.get_residues():
count = count + 1
# print residue,count
a_key = list(dssp.keys())[count - 1]
sec += dssp[a_key][2]
print sec
return sec
This should print both sequence and secondary structure.
You can use DSSP.
The output of DSSP is explained extensively under 'explanation'. The very short summary of the output is:
H = α-helix
B = residue in isolated β-bridge
E = extended strand, participates in β ladder
G = 3-helix (310 helix)
I = 5 helix (π-helix)
T = hydrogen bonded turn
S = bend