Solutions Intermediate Book Answers
Rolan Sacco
I have been running Minizinc models from the command line, and I get final solutions as output.I know I can make Minizic print intermedite solutions in the IDE. How can I make the same from the command line, so that they are printed as output like in the IDE? Btw, I'm refering to the output Minizinc prints by default, not to the 'output' (the one that acts like print) that you can include in the code of the model.
To output intermediate solutions you can use the -a flag on optimisation problems. So for example minizinc --solver gecode -a model.mzn data.dzn will solve model.mzn with data.dzn on the Gecode solver and output all intermediate solutions.
Lately, I've been struggling a lot with plotly, it seemed like I tamed it to match my needs until this problem came up. I'm solving a Job Shop problem with the or-tools solver and use plotly to create an interactive gantt-chart. Everything worked out quite well, but there's still one thing, which would make it perfect. I don't want to simply plot the final result of this mathematical problem, but also the intermediate steps, meaning all the solution the solver finds before it finds the optimal solution. Or-Tools provides on their website code for a solution printer, which met my requirements: it prints the intermediate solutions found. The only problem I'm facing is: I can't plot the intermediate solutions with plotly.
Below you can see the code provided by Or-Tools, I modified it for my problem and it works just fine. It prints the intermediate solutions. As soon as the solver found the optimal solution it continues to my plotly function and plots a gantt-chart. I tried to put the plot function in the on_soltuion_callback function of the class VarArraySolutionPrinter. What happens, it plots the very first solution found and stops the execution of the code. Is there a way in plotly I can plot all solution my solver finds on its way to optimality?
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AWS regions are separate geographical areas, like the US-West 1 (North California) and Asia South (Mumbai). On the other hand, availability zones are the areas that are present inside the regions. These are generally isolated zones that can replicate themselves whenever required.
Auto-scaling is a function that allows you to provision and launch new instances whenever there is a demand. It allows you to automatically increase or decrease resource capacity in relation to the demand.
Geo-Targeting is a concept where businesses can show personalized content to their audience based on their geographic location without changing the URL. This helps you create customized content for the audience of a specific geographical area, keeping their needs in the forefront.
The essential services that you can use are Amazon CloudWatch Logs, store them in Amazon S3, and then use Amazon Elastic Search to visualize them. You can use Amazon Kinesis Firehose to move the data from Amazon S3 to Amazon ElasticSearch.
This is a service that provides a history of the AWS API calls for every account. It lets you perform security analysis, resource change tracking, and compliance auditing of your AWS environment as well. The best part about this service is that it enables you to configure it to send notifications via AWS SNS when new logs are delivered.
This helps you understand the configuration changes that happen in your environment. This service provides an AWS inventory that includes configuration history, configuration change notification, and relationships between AWS resources. It can also be configured to send information via AWS SNS when new logs are delivered.
DDoS is a cyber-attack in which the perpetrator accesses a website and creates multiple sessions so that the other legitimate users cannot access the service. The native tools that can help you deny the DDoS attacks on your AWS services are:
To support multiple devices with various resolutions like laptops, tablets, and smartphones, we need to change the resolution and format of the video. This can be done easily by an AWS Service tool called the Elastic Transcoder, which is a media transcoding in the cloud that exactly lets us do the needful. It is easy to use, cost-effective, and highly scalable for businesses and developers.
Availability zones are geographically separate locations. As a result, failure in one zone has no effect on EC2 instances in other zones. When it comes to regions, they may have one or more availability zones. This configuration also helps to reduce latency and costs.
The image that will be used to boot an EC2 instance is stored on the root device drive. This occurs when an Amazon AMI runs a new EC2 instance. And this root device volume is supported by EBS or an instance store. In general, the root device data on Amazon EBS is not affected by the lifespan of an EC2 instance.
No, standby instances are launched in different availability zones than the primary, resulting in physically separate infrastructures. This is because the entire purpose of standby instances is to prevent infrastructure failure. As a result, if the primary instance fails, the backup instance will assist in recovering all of the data.
Reserved instances, on the other hand, allow you to specify attributes such as instance type, platform, tenancy, region, and availability zone. Reserved instances offer significant reductions and capacity reservations when instances in certain availability zones are used.
To make limit administration easier for customers, Amazon EC2 now offers the option to switch from the current 'instance count-based limitations' to the new 'vCPU Based restrictions.' As a result, when launching a combination of instance types based on demand, utilization is measured in terms of the number of vCPUs.
The point-in-time backups of EC2 instances, block storage drives, and databases are known as snapshots. They can be produced manually or automatically at any moment. Your resources can always be restored using snapshots, even after they have been created. These resources will also perform the same tasks as the original ones from which the snapshots were made.
It can be accomplished by setting up an autoscaling group to deploy additional instances, when an EC2 instance's CPU use surpasses 80% and by allocating traffic across instances via the creation of an application load balancer and the designation of EC2 instances as target instances.
Security best practices for Amazon EC2 include using Identity and Access Management (IAM) to control access to AWS resources; restricting access by only allowing trusted hosts or networks to access ports on an instance; only opening up those permissions you require, and disabling password-based logins for instances launched from your AMI.
Amazon S3 can be used for instances with root devices backed by local instance storage. That way, developers have access to the same highly scalable, reliable, fast, inexpensive data storage infrastructure that Amazon uses to run its own global network of websites. To execute systems in the Amazon EC2 environment, developers load Amazon Machine Images (AMIs) into Amazon S3 and then move them between Amazon S3 and Amazon EC2.
While you may think that both stopping and terminating are the same, there is a difference. When you stop an EC2 instance, it performs a normal shutdown on the instance and moves to a stopped state. However, when you terminate the instance, it is transferred to a stopped state, and the EBS volumes attached to it are deleted and can never be recovered.
The Key-Pairs are password-protected login credentials for the Virtual Machines that are used to prove our identity while connecting the Amazon EC2 instances. The Key-Pairs are made up of a Private Key and a Public Key which lets us connect to the instances.
S3 is short for Simple Storage Service, and Amazon S3 is the most supported storage platform available. S3 is object storage that can store and retrieve any amount of data from anywhere. Despite that versatility, it is practically unlimited as well as cost-effective because it is storage available on demand. In addition to these benefits, it offers unprecedented levels of durability and availability. Amazon S3 helps to manage data for cost optimization, access control, and compliance.
A VPC is the best way of connecting to your cloud resources from your own data center. Once you connect your datacenter to the VPC in which your instances are present, each instance is assigned a private IP address that can be accessed from your data center. That way, you can access your public cloud resources as if they were on your own private network.
You would use Provisioned IOPS when you have batch-oriented workloads. Provisioned IOPS delivers high IO rates, but it is also expensive. However, batch processing workloads do not require manual intervention.
Businesses use cloud computing in part to enable faster disaster recovery of critical IT systems without the cost of a second physical site. The AWS cloud supports many popular disaster recovery architectures ranging from small customer workload data center failures to environments that enable rapid failover at scale. With data centers all over the world, AWS provides a set of cloud-based disaster recovery services that enable rapid recovery of your IT infrastructure and data.
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