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This article mainly introduces the use of the summation function sum in Matlab, which is very detailed and has a certain reference value. Friends who are interested must finish it!

The use of Matlab summation function sum: 1, use [S = sum (A)] to sum; 2, use [S = sum (Ajindim)] to sum according to the specified dimension; 3, use [S = sum (_ _, outtype)] to specify the data type of the output result.

How to use the summation function sum of Matlab:

1. S = sum (A), summation

If x is a vector, the sum of the elements of the vector is calculated, such as:

> > x = randi (10 Personl 10) x = 7 1 9 10 7 8 4 7 2 > > sum (x) ans = 63

If the array of x is the sum of the columns of the computed array, such as:

> > x = pascal (4pm 2) x =-1-1-1-1321 10-3-1001000 > > sum (x) ans = 0 000-1

2. S = sum (A _ cadine dim), summing according to the specified dimension

Dim = 1, indicating the sum of columns

Dim = 2, indicating the sum of rows

Dim = 3, indicating the summation of the page

., and so on.

For example:

> a = toeplitz (1:5) a = 12 3 4 5 2 12 3 4 3 2 12 3 4 3 2 12 5 4 3 21 > > sum (a prime1) ans = 15 12 11 12 15 > > sum (a prime2) ans = 15 12 11 12 15

3. S = sum (_ _, outtype) specifies the data type of the output result

Optional string parameters are 'double','default' and' native'

Generally speaking, the default is' default'

Sometimes we can use this parameter when we sum integers and want the result to be of type double.

For example:

> > a = single (1:4) a = 1234 > > class (sum (a mahjong') ans = double > > class (sum (a)) ans = single

Although the data types of Matlab are comprehensive, the data type conversion is not exactly the same as that of other languages, so you need to be careful when using it.

4. Whether S = sum (_ _, nanflag) ignores nan value

Sometimes when summing, there is the influence of nan value in the data, which leads to NaN in the calculation result. The general processing method is to use the isnan function to exclude the nanvalue. With this option, it is simple.

Such as:

> > a = rand (1Magol 6); a (randperm (6Magne2)) = NaNa = 0.7060 0.0318 NaN 0.0462 0.0971 NaN > > sum (a) ans = NaN > > sum (a) ans = 0.8812 is all the contents of this article entitled "examples of the use of sum in Matlab". Thank you for reading! Hope to share the content to help you, more related knowledge, welcome to follow the industry information channel!

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