Here you will find information about how to create job. We will also explain each section in the creation form.
The job page is the first page you see after logging into the application. Here you have access to all of your jobs and can see their status. The status consists of three variants:
1. Not started
2. In progress
On the job page, you have the ability to perform various actions. These include creating a new job, accessing detailed information about ongoing job processing, viewing results for completed jobs, and comparing different sets of results.
A job, also known as a simulation, encompasses the input data provided by the user. Upon completion, it includes the generated results corresponding to that particular job.
To create a job, you need to fill in data about the system. When starting, you have the option of creating a job from scratch or base it on a previous system you already made.
A system is all specifications that are needed to run a job. This entails the composition as well as the external conditions, such as temperature and pressure. A system name is specified by the user only to make it easier to keep track of different jobs. An example of a good system name is “LP30, T=25”.
Composition is a detailed description of the molecules in the system, and it is divided into solutes and solvents. In practice, the distinction between the two lies in the specification of the amount of each solute relative to the solvent (using measures like molar or weight-%). Meanwhile, the amount of solvent is automatically adjusted to ensure a simulation box of manageable size. A solute can be a mixture of multiple components (such as EC and DMC), in which case it is necessary to specify the relative proportions between them (using, for example, weight or mole fractions).
Conditions are the external constraints that the system will be exposed to during the simulation. The meaning of the different conditions depends on the choice of ensemble.
The constraints for the system are set by the conditions, and depending on the ensemble type, specific conditions must be provided. Except for “other information,” all conditions are mandatory and must be provided.
You have the option to select from three ensemble variants: NVE, NVT, and NPT. The difference between these three ensembles relates to whether the volume and/or the total energy is kept fixed. In the case of a fixed volume (V), the pressure (P) will vary, and vice versa. Similarly, in the case of fixed energy (E), the temperature (T) will vary, and vice versa. The letter N stands for a fixed number of atoms, which is always the case in our simulations.
1. NVE means fixed volume and energy.
2. NVT means fixed volume and temperature.
3. NPT means fixed pressure and temperature. This is the recommended choice unless you have a good reason for picking another.
The temperature can be specified in Celsius (°C), Fahrenheit (°F) or Kelvin (K), whichever is more convenient for you. You should typically use a value close to the working conditions of your system.
If you use the NVT or NPT ensemble, the temperature during the simulation will very closely match the temperature you specify here.
If you use the NVE ensemble, the specified temperature will merely define the kinetic energy of the starting point of the simulation, and the temperature will typically change drastically throughout the simulation.
Pressure is a required parameter only for the NPT ensemble. It defines the approximate pressure that the simulation will be driven to. Note, however, that pressure typically fluctuates wildly in atomic-scale simulations, and it is hard or impossible to resolve small differences in pressure. Pressure can be specified in units of Pa, atm, bar, psi or mmHg.
The value you specify for density enables the estimation of the volume of the simulation cell. When using NPT ensemble, a rough approximation is sufficient (you can use 1 g/cm³ if unsure), as the simulation cell will dynamically adjust during the simulation to achieve the correct density based on temperature and pressure. In the NVE and NVT ensembles, the density will not change, meaning that your specification here is important. The density can be specified in g/cm3 or kg/m3.
Use the “Other information” section to pass information to Compular’s simulation engineers. They will review this information before starting the job, and it can be handy if you want expert input or review before investing computational resources.
You have the flexibility to save, delete, or submit the create job form along with the system data for analysis. Saving the form does not run the system, but only saves it on your account, providing the convenience of accessing it at a later time. Jobs labeled as “not started” in the job list indicate they have only been saved.
By deleting the system, it is removed from your account. Systems that have been deleted cannot be recovered.
When satisfied with the form, you can click on the “Analyze system” button to send the information for processing. Before sending the system for processing, you will receive a summary encompassing the information you have filled in about the system. This information contains a suggestion for the number of molecules of each species to include in the simulation to as closely as possible match the composition you specified, while keeping the computational workload manageable. You can still edit this suggestion by simply changing the number of molecules of each species. When you are happy, you click “Submit job”.
When the system data has been sent for processing, it can no longer be edited. Instead, cancel the job (see In progress) and create another job.