Matlab Program Runs Once but Not Again

Definition of Nested Loop in Matlab

Nested Loop is a compound statement in Matlab where we can place a loop inside the body of some other loop which nested form of conditional statements. As you lot accept known that, Matlab allows you to combine some chemical compound statements like IF, FOR & WHILE inside other chemical compound loops. This nesting loop is called a nested loop in Matlab. You should note that yous can put ane type of loop inside another type of loop.

Generally, a loop is a repetitive code function that efficiently allows you to execute the conditional statements a specific number of times you need. Thus, a Nested Loop defines a concept to use an inner loop within the body of the outer loop in the code statements. When executed the loop gets triggered passes to the outer loop and so the inner once again. This process continues until the outer loop fulfills the status and this is interrupted past the pause statement which further proceeds to provide the required result.

Syntax:

Following is the syntax of the nested loop in Matlab with 'For' loop statement:

for m = 1:i
for n = i:i
[statements] finish
end

Here 'I' represents the number of loops yous want, to run in the nested loop and the statements define the condition or numeric expression of the code. Likewise, the nested loop for WHILE loop statement in Matlab:

while [expressions1] while [expressions] statements
end
end

Flowchart

The following figure defines the flow chart for Nested Loop in Matlab:

How Nested Loop Works in Matlab?

As per the above syntax, the following is an example of a nested loop in Matlab.

a = 0;
for m = one:v
for north = 1:5
a = a+thousand+due north;
finish
end

But when we look at the above loop construction in Mathematics term then, it seems that we are calculating the sum as _grand=1∑⁵ _n=1∑⁵ (m + northward). This tin be calculated to give the beneath event:

As nosotros take taken i=5, then

i2(i + 1 ) = 5ii * 6 = 150

This is what you go in MATLAB:

a = 0;
for m = 1:5
for n = ane:5
a = a + m + n;     >>>>>150
end
end

How to Exit a Nested FOR Loop?

Inappropriately, there is no smart method in my noesis to exit every nested loop and run the remaining code part. Generally, nosotros need to repeat the status each time to exit the FOR loop. You can view the post-obit syntax:

for m = 1:i
for n = i:i
[conditional statements] if conditionforbreak
break
end
end
if conditionforbreak
suspension
cease
cease

Suppose if nosotros have the previous instance to implement break to get out the loop, and then nosotros will get:

a = 0;
for chiliad = 1:five
for north = 1:5
a = a+m+north;
conditionforbreak = a>100;
if conditionforbreak
break
terminate
end
if conditionforbreak
end
finish

This provides the beneath outcome in Matlab:

If a = 109 or greater value than 100 so it will put a break and leave the loop. Note that 'a' does not repeat in a unmarried increase, so it assures that the next repeat of 'a' is non 101.

Examples of Nested Loop in Matlab

For case to apply the nested loop nosotros tin write the post-obit code to evidence all the prime numbers from 1 to 50. We need to create a script file and code the following nested loop statements.

for m=2:fifty
for n=ii:fifty
if (~mod(grand,n))
break;
cease
end
if(one thousand>(m/north))
fprintf('%d is prime \n', chiliad);
end
terminate

When you execute the in a higher place file yous will go the consequence below:

Output:

Here, in Matlab, nosotros can execute the code inside the iterative statements. In this code, nosotros have nested the IF loop in the trunk of the argument. We can continue this every bit many times as required. Likewise, we tin nest FOR loop inside other FOR loops and the WHILE loop tin can besides be executed in the class of a nested loop to write the statements.

% to create a multiplication table and the result is saved as 10.

rows 1:ten
cols 1:x
for a = rows
for b = cols
A(a,c) = a*b;
end
finish

We need to call back that along with whatsoever statement that is put in an inner FOR loop, a nested FOR loop is run in one case for each value of the surrounding loop. Talking about the in a higher place code script, the outside loop i.east. the loop for 'a = rows' is executed 10 times every time for each value of a. On the other hand, every fourth dimension the inside loop i.east. the loop for 'b = cols' modifies x different entries, one with respect to each value of 'b' in the Ten matrix. Finally, we will go the output of full 100 i.e. '=10*x' entries or values in table X which is updated.

Indentation

Reliable use of indentation allows creating a readable code especially while using nested IF and FOR loops together. We can employ the smart Indent characteristic provided by MATLAB editor then that nosotros can confirm the code added is valid for the nested loop statement, like using (TEXT ->SMART INDENT). If the indentation is not proper so, it may hide whatsoever errors or problems.

Avoid or Cease a Nested Loop with A Interruption Statement

A BREAK statement provides logical output only within a loop. We should also understand to know the Interruption statement is used only with the innermost loop that encloses a BREAK statement. In Matlab, there are several means of creating a FOR loop. Let united states talk over a simple syntax with an case to write the loop:

for j = 1:k  % k is the number of loops that we want
conditions;  % the condition to exist fulfilled for loop to execute it
end

Now let the states create the loop:

for j = 1:5
j
stop

Output:

Conclusion

Hence, the Nested Loop is a control construction that helps to iterate a given section of the loop statement until it meets a satisfying status and and then information technology terminates. Yous need to write the loops as scripts and not directly to the command window like locating the button in the upper left corner from the NEW Script option. In this commodity promise you might take learned some new concepts regarding the Nested loop in MATLAB.

Recommended Articles

This is a guide to Nested Loop in Matlab. Here we hash out the definition and how nested loop works in Matlab along with flowchart and examples. You may also look at the following articles to learn more –

1. Various Types of Loops in MATLAB
2. Examples of Meshgrid in Matlab
3. Introduction to Colormap in Matlab
4. ismember Functions in MATLAB
5. Guide to Nested Loop in C++

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