Что значит nan в матлабе
Description
NaN returns the IEEE arithmetic representation for Not-a-Number ( NaN ). These result from operations which have undefined numerical results.
NaN(‘double’) is the same as NaN with no inputs.
NaN(‘single’) is the single precision representation of NaN .
NaN(n) is an n -by- n matrix of NaN s.
NaN(m,n) or NaN([m,n]) is an m -by- n matrix of NaN s.
NaN(m,n,p. ) or NaN([m,n,p. ]) is an m -by- n -by- p -by-. array of NaN s.
NaN(. classname) is an array of NaN s of class specified by classname . classname must be either ‘single’ or ‘double’ .
These operations produce NaN :
-
Any arithmetic operation on a NaN , such as sqrt(NaN) Addition or subtraction, such as magnitude subtraction of infinities as (+Inf)+(-Inf) Multiplication, such as 0*Inf Division , such as 0/0 and Inf/Inf Remainder, such as rem(x,y) where y is zero or x is infinity
Because two NaN s are not equal to each other, logical operations involving NaN s always return false, except
Как подсчитать NaN в MATLAB (за 3 шага)
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Содержание
В среде математического программирования MATLAB NaN — это специальное значение, которое означает «не число». Значения NaN могут возникать в ваших переменных в случаях, когда происходит необычная операция, например деление нуля. Это также может происходить в некоторых бесконечных операциях, представленных как + Inf и -Inf в MATLAB. Значения NaN также могут возникать при импорте данных из поврежденных файлов или необычных форматов. MATLAB предлагает специальные функции для работы с матрицами, содержащими значения NaN.
Шаг 1
Создайте или получите массив, содержащий значения NaN: Например, myArray = nan (m, n); "создает массив значений NaN размером m на n для переменной myArray.
Шаг 2
Определите, равно ли каждое значение NaN, используя функцию isnan (). Это необходимо, поскольку обычные логические операции, такие как «==», не могут сравнивать значения NaN. Следуя приведенному выше примеру:
myBooleanArray = isnan (myArray);
Шаг 3
Суммируйте значения в myBooleanArray, чтобы определить количество значений NaN, содержащихся в myArray. В MATLAB сумма операций работает только с последним измерением. Итак, в приведенном выше примере myArray m-by-n вам нужно либо вызвать:
how_many_NaNs = сумма (сумма (myBooleanArray));
how_many_NaNs = сумма (изменить форму (myBooleanArray, m * n, 1));
Во втором примере кода массив реконфигурируется в одномерный массив, так что сумма функции работает по всему массиву.
Что значит nan в матлабе
Description
NaN returns the IEEE arithmetic representation for Not-a-Number ( NaN ). These result from operations which have undefined numerical results.
These operations produce NaN :
-
Any arithmetic operation on a NaN , such as sqrt(NaN) Addition or subtraction, such as magnitude subtraction of infinities as (+Inf)+(-Inf) Multiplication, such as 0*Inf Division , such as 0/0 and Inf/Inf Remainder, such as rem(x,y) where y is zero or x is infinity
Because two NaN s are not equal to each other, logical operations involving NaN s always return false, except
What is NaN in MATLAB
NaN values are different from all other numbers, including themselves. This means that if you compare a NaN value to another number, the result will always be false.
How is NaN Created?
NaN values can be created by a variety of operations in MATLAB, including:
- Division by zero
- Overflow
- The NaN functions
What Does NaN Mean?
NaN values mean that the result of an arithmetic operation is undefined. This can happen for a variety of reasons, such as trying to divide by zero or trying to store a number that is too large or too small to be represented in MATLAB.
The NaN values have different behavior than other numbers in MATLAB. For example, NaN values cannot be compared to other numbers, and they cannot be used in arithmetic operations.
How to Deal with NaN in MATLAB?
There are a few ways to deal with NaN values in MATLAB:
Test for NaN Values
The isnan() function can test if a value is NaN. Below, given MATLAB code will test if the variable x is NaN:
Fill NaN Values
To fill NaN values with another value, we can use the below-given code syntax. Now we will execute the below code that will fill the NaN value in the variable x with the value 1:
Ignore NaN Values
The omitnan() option can be used to ignore NaN values in some MATLAB functions. For example, the following code will calculate the sum of the elements in the vector x, ignoring any NaN values:
How to Prevent NaN in MATLAB?
There are a few ways to prevent NaN values in MATLAB:
Avoid Division by Zero
Division by zero can easily output NaN values. To avoid NaN values occurring due to zeros, we can check for the zero before we start a division of the number. The below given MATLAB code will check if the variable x is equal to zero before it divides by x:
Avoid Overflow
Overflow can also create NaN values. You can avoid overflow by checking if a number is too large or too small before you store it in MATLAB. The below MATLAB code will check if the variable x is greater than the maximum value that can be stored in MATLAB:
Conclusion
NaN values are a special type of value in MATLAB that represents undefined or missing numbers. They can be created by a variety of operations, and they behave differently from other numbers in MATLAB. We have different ways in MATLAB to deal with NaN values. To avoid NaN values, avoid both divisions by zero and overflow. Read more here.
About the author
Kashif
I am an Electrical Engineer. I love to write about electronics. I am passionate about writing and sharing new ideas related to emerging technologies in the field of electronics.