(In fact, false (and true) are also built-in MATLAB functions: false takes no arguments and returns a logical zero.) Note the MATLAB "core" is quite large compared to other languages such as Python, in which most functions must be explicitly brought in as modules. All of the functions we describe in the preceding paragraph are "built-in" functions that are part of the core MATLAB scripting language we shall exercise these functions in the next section once we are armed with the assignment operation. For now, think of a function as a program which takes some (zero, one, two, or many) input arguments and yields some output we provide illustrations in the next section. We do not fully define functions until a later chapter, in which we learn how to create our own functions. We already above and will frequently below refer to functions. We can also determine what type of data a particular variable is with the islogical, isinteger, ischar, and isfloat functions. It is, however, possible to specify that any particular variable is logical, with the logical function, an integer, with the (say) int32 command, a character, with the char command (or more simply with quotes), and a floating point number, with the double command. MATLAB is much less picky than other programming languages - a blessing and a curse - and typically if no type is specified MATLAB will simply assume a (double) floating point number, which is hence the "default." (We define variables in the next section - for now, think of a variable as the name of a particular piece of data.) Each variable must be an instance of one of the available (in our case, MATLAB ) data types. In some programming languages the user is required upon creation of a variable to specify the data type. These types are "atomic" in that they are part of the core MATLAB scripting language. MATLAB also supports a complex floating point type. Representation of floating point numbers (FPNs) by a 64 bits is probably less obvious than representation of a whole number, and hence we will discuss representation of FPNs, and also floating point operations, in a separate section. And particularly important for us, there are floating point numbers, which in MATLAB are 64 bits and are called (for largely historical reasons) simply double. There is character data, in which the 0 ’s and 1’s encode particular characters such as letters in the alphabet or numerals - the famous ASCII code and recent extensions. There is integer data - a signed whole number. ![]() There are logical variables which are either 0 or 1 which correspond respectively to (and in fact the data may be entered as) false or true. ![]() ![]() ![]() There are several important types within MATLAB (and homologous types within other programming languages). As regards the latter, we note that the same set of 0 ’s and 1’s can mean something very different - and be operated on in very different ways - depending on the data type associated with these 0’s and 1’s. Furthermore, there are many different type of data: any piece of data is defined not just by the 0’s and 1’s that make up the word, but also by the "data type" which tells the computer how to interpret and operate upon the data. Most machines these days are based on 32-bit or 64-bit words (which are 4 Bytes and 8 Bytes, respectively) in some cases particular data types might be represented by two words (or more).īut obviously we will need to interpret these 0’s and 1’s in different ways: in some cases the 0’s and 1’s might represent machines codes (instructions) which tell the arithmetic unit what to execute in other cases, the 0’s and 1’s might represent data on which the the instructions will operate (the "operands"). The basic unit of memory is the "word-length" of the machine - the number of binary digits, or "bits," which are used to represent data. This is most convenient as binary operations are very efficiently effected in terms of the necessary nonlinear circuit elements. \)Īll data in the computer is stored as 0’s and 1’s - binary digits.
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