THE ELEMENTS OF MATLAB STYLE PDF
This page intentionally left blank The Elements of MATLAB R Style The Elements of MATLAB Style is a guide for both ne. Cambridge Core - Science Handbooks - The Elements of MATLAB Style - by Richard K. Johnson. Access. PDF; Export citation. Contents. pp v-viii. Access. For broader and deeper coverage of MATLAB style and best The Elements of MATLAB Style available at .. or pdf can produce basic reports. MATLAB can.
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“The Elements of MATLAB Style”. - by Richard K. Indent Consistently with the MATLAB Editor. . Consider Providing PDF Documentation. Comments. 2 Johnson, R., ”Matlab programming style guidelines.” USA Datatool MathWorks developer (for “Elements of MATLAB style” by R. Johnson)2. Elements of MATLAB. Lloyd D. Fosdick. Elizabeth R. Jessup. Carolyn J. C. Schauble. 19 August Revised. February 20, High Performance Scienti c.
Make input and output modules for large functions. Just don't do it. Format output for easy use. For humans, make it human readable. Short single statement if, for, or while statements can be Constants For machines, make it parsable.
Named constants should be all uppercase using underscore to separate words. Constants can be prefixed by a common type name.
Structures Related variables of the same type can be declared in a common Keywords should be followed by a space. Structure names should be mixed case and begin with a capital statement. Unrelated variables should not be declared in the same Blocks of code should be separated by three blank lines or a letter.
Car, DumpTruck persistent x, y, z Use code alignment wherever it enhances readability. Do not include the name of the structure in the field name. Document important variables in comments near the start of the Use Segment. Comments Document constants with end of line comments. If you choose to do it, then insert spaces to help the reader distinguish statements from expressions.
Use of this extra spacing is tedious to apply consistently and does not enhance readability. When you avoid inserting this space, it is easier to distinguish the function and command forms. Do follow a keyword with a space so that it does not look like a function. Maintaining the alignment when the code is changed is much more trouble than it is worth. Code Blocks Each block should be cohesive, performing a task such as initializing variables, checking parameters, or computing a task.
This allows single blank lines within a long code block while still helping the entire block stand out from the adjacent blocks. The number of blank lines can depend on context. For example, fewer lines are appropriate when followed by a comment for the next code block. This approach might have been helpful when programs were primarily viewed on a line printer listing.
It is no longer as important now that comments are displayed in a different color from statements in the Editor. Use Editor Cells Most code will be read in an editor. In addition to supporting selective execution, cells enhance readability in the Editor and support the Publish feature. A cell break or a cell break after a blank line provides enough visual separation to adequately distinguish code blocks.
Formatting Summary Format the code to make it more readable. Avoid long lines and multiple statements per line so that the code is easier to scan. Indent consistently to reveal logical structure. Use spaces consistently in appropriate places to make each line easier to read and interpret.
In particular, insert spaces around operators and expressions to reveal the structure and meaning of statements. Write your code in logical blocks that can be read as paragraphs so that the program can be understood in chunks.
Use blank lines, comment lines, and Editor cell breaks to make these blocks easy to see.
Naming The purpose of a software naming convention is to help the people who read and write the code understand the program. Understanding the code makes it easier to use, write, or modify correctly. The goal in naming is to use names that are easy to recognize and associate with their meaning and role. The basic content idea is to use words and character sequences that help connect a name with the entity that it represents.
It is a great idea to use names that are intuitive, but developers have surprisingly divergent ideas on which names are intuitive.
A more realistic objective is to use names that help the reader understand the code. This makes it easier to recognize the various elements of the language. Clearly, some consistency and differentiation is important. There is a balance in differentiation because having a large number of styles makes for too much to remember.
In any case, only a few variations of naming style are available in MATLAB, so the language elements have to be grouped into a smaller number of styles. There is controversy is over how best to do it.
Establishing a naming convention for a group of developers is important, but the process can become ridiculously contentious. There is no naming convention that will please everyone. Following a convention consistently is more important than the details of the convention.
Inconsistent practices confuse readers and raise legitimate concerns about code quality. Good names are very helpful to both the reader and the programmer. However, coming up with good names is not easy. Keep trying until you get them right. Names should be easy to remember and easy to associate with a meaning. They should also be responsive to their environment not too short or long. Trade-offs are likely to be required. Both attributes make the code easier to read, write, and use. Put the elements of compound names in familiar order.
Replace lengthArm with armLength If the software is targeted for a knowledge domain or a user group, then use names consistent with standard practice in that domain or by that group. Organize the data so that it makes sense to use one name or multiple distinctive names.
Similarly, avoid mixing similar action terms such as fetchaccount, retreivestore, returncustomer, getinventory for the same general functionality. Long names are particularly problematic in visually parsing expressions.
Because very long names decrease the readability of expressions and statements, the best names are those just long enough to be descriptive. Replace applyThresholdToDataArray with applyThreshold The goal in choosing names is not necessarily to give everything complete and proper names, but rather to give them comprehensible and trackable names.
Programmers are used to some shortening in compound words, but do not overdo it. Using whole words reduces ambiguity and helps make the code self-documenting. Because they are often not unique, abbreviations are prone to interpretation and typing errors. Use computeArrivalTime Avoid comparr In this case, it is unclear whether the intent is compute or compare. For example, html, cpu, cm Use the same convention for capitalizing acronyms as for words.
Avoid Names that Differ Only by Capitalization Names that differ only by capitalization are easy to confuse, and this is an almost certain way to introduce defects. Consistent capitalization is one of the hallmarks of good style.
Do not use FlightTime or Flighttime in the same module in which you use flightTime. Authors of books and papers sometimes use names such as x and X together for related but distinct entities. They also increase the likelihood of unintentional use. Code written by novices often includes names like a1, a2, a3 or a, aa, aaa. This is usually evidence that the names are not meaningful.
Even names that carry some meaning can be problematic if they only differ by one number or letter. Also avoid using lowercase l or uppercase O as a single-letter name. The audio cues can make names easier to hold in shortterm memory. Pronounceable names improve communication with other programmers and also reduce the likelihood of typographic errors.
Variables and Parameters Variable names should be easily remembered by the programmer and have a suggestive value for readers; that is, they should help us recognize the meanings of the variables. They should also be consistent with the names of similar variables.
Avoid Ambiguous or Vague Names A good name distinguishes one variable from another. A variable name that has to be deciphered should be changed. Names such as temp1 and vec convey little meaning. If used, they should be limited to very small scope. Be selective in the use of numbers at the ends of names.
The appearance of numbers at the ends of variable names often indicates poor naming. Including type or class in a variable name creates a headache if the type or class is changed.
MATLAB Style Guidelines Cheat Sheet: Naming Conventions
For example, use linearity, delta Very short variable names can be in uppercase if they are uppercase in conventional usage and if they are unlikely to become parts of compound variable names. Examples include V and R in electrical engineering and Q in signal processing.
The use of capital letters makes it easier to recognize the individual words in the variable name. Starting variable names with uppercase is usually reserved for objects, types, or structures in other languages. This practice is common in Unix. Although readable, this usage is generally unexpected and not common for variable names in other languages.
A descriptive or meaningful name is especially important when a variable is used in code locations that are far apart.
Names that are too short are a common problem that obscures meaning; that is, it is easier to understand and remember the meaning of salary than s.
Limit Use of Very Short Names to Variables with a Small Scope The use of short names should be reserved for conditions in which they clarify the structure of the statements or are consistent with intended generality. In a general-purpose function, it may be appropriate to use short generic variable names such as x, y, z, and t.
Scratch variables used for temporary storage or indices can have short names because they do not need to be remembered outside local scope. Variable names in different local scopes also do not need to be unique. Be Consistent With i and j The letters i and j have long been used as both imaginary numbers and indices or loop counters.
Those who favor this usage can establish a different variable for imaginary numbers, such as I, J, or jay, or use an expression of the form 1i, which The MathWorks recommends for speed and robustness.
Those who favor saving i or j for the imaginary number can use different loop counter variable names such as iSample or I.
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Avoid using both j and J in the same scope because they look similar and thus can be easily confused. Be especially careful to avoid unintended mixing of the singular and plural names.
The most important consideration in this guideline is to distinguish clearly between a single entity number and the number of entities. This practice may be suboptimal, particularly if the loop is long, because it misses an opportunity to reinforce the meaning of the loop index.
For nested loops, the iterator variables should usually be in alphabetical order. Alternatively, some mathematically oriented programmers use a variable name starting with i for rows and j for columns, independent of their position in nested loops.
Embed is, has, etc. Avoid Negated Boolean Variable Names A problem arises when such a name is used in conjunction with the logical negation operator because this usage results in a double negative.
Use the Expected Logical Names and Values A true or valid condition is usually associated with a positive integer or a logical true; a false or invalid condition is usually associated with zero or a logical false. It is generally poor practice to rely on this somewhat confusing behavior. Reserved words are listed by the command iskeyword. Also avoid using a variable name that differs from a keyword or special value only by capitalization or a single letter. These names can be ugly, particularly when they are strings of contractions or abbreviations.
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If the type needs to be changed, then all incidences of the variable name need to be changed. This practice can be problematic if use of the variable changes to include, for example, two-dimensional arrays. Such usage in scripts will shadow the functions and can lead to errors. Using a variable and a function with the same name inside a function will probably cause an error. Some standard function names that have appeared in code examples as variables are alpha, angle, axes, axis, balance, beta, contrast, gamma, image, info, input, length, line, mode, power, rank, run, start, text, type Using a well-known function name as a variable name also reduces readability.
Avoid Reusing a Variable for Different Contents When a variable is reused, its purpose is unlikely to be clear from its name. Reuse variables only if memory is a constraint. If you change the meaning of a variable, then also change its name. Similarly, avoid giving two interpretations to a single variable, such as a hidden meaning as well as a normal meaning. We use naming conventions to provide a visual cue that a variable is being treated as a constant.
The best naming and usage practices can depend on the scope of the constant. If the constant has a compound name, then use an underscore as a separator. For example, you can use c for the speed of light or h for the Planck constant. Each constant is the output of a function with the same name as the constant.
This practice makes it easy to avoid most of the problems with global constants. It is also graceful in expressions.
Use Meaningful Names for Constants As with variable names, the goal is to make it easier for the reader to remember what the name means. Use Fieldnames that Follow the Naming Convention for Variables Structures are convenient for passing variables into and out of functions. Name Cell Arrays Following the Style for Variables The names of cell arrays should follow the convention for simple variables and arrays. Remember that the goal of different naming styles is to help the reader understand the code.
Making their names easy to scan and understand is critical to readability. Try to use function names that succinctly convey what the functions do and suggest how to use them. The selection of a useful name depends on what the function does and what if anything it returns. Give Functions Meaningful Names The purpose of a well-named function or method can often be determined just from its name.
This concern is no longer relevant and the tradition should usually be avoided to improve readability. Naming the function after this action increases readability, making it clear what the function should and possibly should not do. Also, this usage can make it easier to keep the code clean of unintended side effects.
Typically, function names should start with a verb: plot, reviseforecast You can also name functions for their output. This practice is appropriate if the name would otherwise begin with a common computing verb such as compute or find. Naming a mathematical or statistical function for its output is common practice in MATLAB code: mean, standarderror, localmaxima It works well for single-word names and reasonably well for short compound names.
This practice also helps distinguish function names from lowerCamelCase variable names or UpperCamelCase object names. This practice is especially popular for functions that are class methods. Function names often begin with a verb, which helps distinguish them from variable names. For longer compound names, lowerCamelCase is more readable than all lowercase: removeVaryingBias, adjustHistogramBins These are the preferred conventions, and their use can be mixed.
T attribute, which returns the transpose of the data. I, and.
A attributes, which return the conjugate transpose, inverse, and asarray of the matrix, respectively. Convenience constructor The array constructor takes nested Python sequences as initializers.
As in, array [[1,2,3],[4,5,6]]. The matrix constructor additionally takes a convenient string initializer. A v treats v as a column vector, while v A treats v as a row vector. This can save you having to type a lot of transposes. To hold three-dimensional data you need array or perhaps a Python list of matrix.
You cannot have vectors. They must be cast as single-column or single-row matrices. Interaction with scipy. The array is thus much more advisable to use. Indeed, we intend to deprecate matrix eventually.
These are not exact equivalents, but rather should be taken as hints to get you going in the right direction.Understanding the motivation will help you decide what to do. The syntax options should start with the most basic options, and then detail the rest of the calling forms. They are really variables that are, or should be, resistant to change. This is machine translation Translated by Mouseover text to see original.
When you avoid inserting this space, it is easier to distinguish the function and command forms. The Dirichlet boundary condition is posed by assign the function values at Dirichlet boundary nodes bdNode.