Guide To Learn
One of the key elements of almost every computer program is taking different execution paths (branches) depending on some criterion. Take, for example, a program that parses a bank account registration form for a customer. If one of the input fields isn’t entered correctly, such as a Social Security number having letters or a name […]
Now that you have an idea of how to declare a variable of a specific numeric type, let’s declare some variables, constants, and arrays that we’ll use in the tsunami simulator. Declaring variables What kinds of variables will we need? As a reminder, based on our implementation strategy in section 2.3.1, we’ll need the following: […]
Fortran provides three numerical data types out of the box: integer, real, and complex. Integer numbers The integer is the simplest numeric type in Fortran. Here are some examples of integer literals: You declare one or more integers like this: This statement instructs the compiler to reserve the space in memory for integer variables i and n. It’s made of the […]
Explicit is better than implicit. –Tim Peters The first part of any program unit is the declaration section. Fortran employs a static, manifest, strong typing system: Implicit typing Fortran has a historical feature called implicit typing, which allows variable types to be inferred by the compiler based on the first letter of the variable. Yes, you read that right. Implicit […]
The main program is the fundamental program unit in Fortran. It allows you to assign a name to your program and defines the program scope, as shown in the following listing. Listing 2.3 Defining the program unit and scope program tsunami ❶ end program tsunami ❷ ❶ Begins the new program and gives it a name […]
Before we do any coding, it will be helpful to sketch out our tentative strategy for implementing the first version of our app: Sound good? Let’s dive in and tackle these one at a time.
Having set the problem to solve, we’ll soon be able to dive into Fortran coding. But first we’ll go over the implementation strategy (you should always have one) in the next subsection. Then, we’ll go over the core elements of the language and apply them to implement the first version of the tsunami simulator.
Wikipedia defines advection as “the transport of a substance or quantity by bulk motion.” Advection is a fundamental process in physics, engineering, and earth sciences. It governs how a solid object or a fluid moves in space because of background flow. When a swimmer is swimming against the current, they’re advected by the current, and […]
At this stage, we’ll simulate only the movement of an object (or fluid) due to background flow. This will provide the foundation for other physical processes that we’ll add to the solver in later chapters. Simulating only one process for now will guide the design of our program structure and its elements: declaration and initialization […]
Near the end of the previous chapter, I introduced the shallow water system of equations, which we’ll work to solve over the course of this book to produce a realistic simulation of a tsunami. Here we’ll start implementing the simulator from scratch, both in terms of the source code and the physics that we’ll simulate […]