Load balancing: Cant understand Summation Term

[zak100]

Hi,

I am trying to understand the following text. I can’t understand the term Summation of (j tj). Are we multiplying j and tj. But the text is not talking about multiplying, it says”Total processing time.

 

 

 

Somebody please guide me.

 

Zulfi.

 

 

Hi,

Thanks. Its not "j * tj"

 

Zulfi.

I got it.

 

Zulfi.

[Sensei]

Are you familiar with mathematical summation?

https://en.wikipedia.org/wiki/Summation

 

If t is array/list of elements/pointer to memory etc. j is index to element. And t_j is value of element i.e. t[ j ] in computer language.

So summation of array etc. is e.g:

int *t;
int sum = 0;
for( int j = 0; j < length; j++ ) {
	sum += t[ j ];
}

 

However, in the special cases, if t_j is always constant it can be replaced by multiplication (addition of the same value multiple times).

Edited April 29, 2020 by Sensei