# tic

Start stopwatch timer

## Syntax

``tic``
``timerVal = tic``

## Description

example

````tic` works with the `toc` function to measure elapsed time. The `tic` function records the current time, and the `toc` function uses the recorded value to calculate the elapsed time.```

example

````timerVal = tic` stores the current time in `timerVal` so that you can pass it explicitly to the `toc` function. Passing this value is useful when there are multiple calls to `tic` to time different parts of the same code. `timerVal` is an integer that has meaning only for the `toc` function.```

## Examples

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Measure the time required to create two random matrices.

```tic A = rand(12000,4400); B = rand(12000,4400); toc```
```Elapsed time is 0.743248 seconds. ```

Measure the elapsed time since a call to the `tic` function at different points of the program.

```tic A = rand(12000,4400); B = rand(12000,4400); toc```
```Elapsed time is 1.436023 seconds. ```
```C = A.*B; toc```
```Elapsed time is 1.634381 seconds. ```

Use a pair of `tic` and `toc` calls to report the total time required for element-by-element matrix multiplication; use another pair to report the total runtime of your program.

```tStart = tic; % pair 2: tic n = 10; T = zeros(1,n); for i = 1:n A = rand(12000,4400); B = rand(12000,4400); tic % pair 1: tic C = A.*B; T(i)= toc; % pair 1: toc end tMul = sum(T)```
```tMul = 0.5585 ```
`tEnd = toc(tStart) % pair 2: toc`
```tEnd = 14.8667 ```

The variable `tMul` includes the total time spent on multiplication. `tEnd` specifies the elapsed time since the call to the `tic` function at the beginning of the program.

## Tips

• Consecutive calls to the `tic` function overwrite the internally recorded starting time.

• The `clear` function does not reset the starting time recorded by a `tic` function call.

• Sometimes programs run too fast for `tic` and `toc` to provide useful data. If your code is faster than 1/10 second, consider measuring it running in a loop, and then average to find the time for a single run. For more information, see Measure the Performance of Your Code.

• The following actions result in unexpected output:

• Using `tic` and `toc` to time `timeit`
• Using `tic` and `toc` within a function timed by `timeit`

## Version History

Introduced before R2006a