Adding statistical distribution in global tables

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Marc K asked Jul 30, '19 Joseph Gillespie commented Aug 5, '19

Adding statistical distribution in global tables

I have processes that are variable each time they are ran. I created a Global Table to contain the time variables. If I enter a single number variable (i.e. 5 for 5 minutes) the lookup works. I needs the value to be a statically distributed (i.e. triangular(5.0, 15.0, 10.0, getstream(current))). When I input this string the Global Table does not work. Like Excel where you put an "=" sign to designate it as an expression, is there a simple way to do that in Flexsim? This way when I have my DELAY look up the table the Delay becomes variable. I know I can just have the DELAY have the expression but having the ability to modify the table is far easier than going through all DELAYS in my model.

Software Version:

FlexSim 19.0.1

global tables

Answer 1 · 2019-07-31T08:11:42Z

Mischa Spelt answered Jul 31, '19 Joerg Vogel commented Aug 1, '19

First of all you should make sure to tell FlexSim that you want to put a script in your cell. Right click the table cell, select Assign Data, then Assign FlexScript Data (or do it on the whole column at once).

Since there will not be a current variable, you should replace the last argument with a hardcoded one such as 1 or getstream(Table("tablename")).

Now each time you request the value of the cell

Table("GlobalTable1")[1][1]

it will return a random value.

Note that you will have to be careful not to write code like this:

if(Table("GlobalTable1")[1][1] < 0.5) {
  item.RandomValue = Table("GlobalTable1")[1][1];
}

but like this, only executing the cell once:

double randomValue = Table("GlobalTable1")[1][1];
if(randomValue < 0.5) {
  item.RandomValue = randomValue;
}

Alternatively, you can just put the cell data type to String, and then instead of

Table("GlobalTable1")[1][1]

use something like

Table("GlobalTable1").executeCell(1, 1)

to execute it.

· 8

Marc K commented · Jul 31, 2019 at 11:58 AM

This is what I think you are saying but it doesn't work. I get error messages. Is the Equation correct in the table cell?

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globaltable.png (40.6 KiB)

Marc K commented · Jul 31, 2019 at 12:04 PM

Mischa, is this what I am doing wrong? I did not fully understand this statement...

"Since there will not be a current variable, you should replace the last argument with a hardcoded one such as 1 or getstream(Table("tablename"))."

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Joerg Vogel Marc K commented · Aug 01, 2019 at 11:27 AM

you can parse parameters into the code of a table cell, if you evaluate the cell node.

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evaluate-params-at-table-cell.jpg (204.2 KiB)

Marc K Joerg Vogel commented · Aug 01, 2019 at 12:31 PM

Jorg, what is the advantage of doing this way compared to the answer Mischa gave. I am always trying to learn.

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Mischa Spelt Marc K commented · Aug 01, 2019 at 07:59 AM

Yes, you cannot use current there. Normally, when you use an object trigger or Process Flow activity, FlexSim will automatically add a code header with a current variable that points at the current object or attached Process Flow object. In this case there is no such default header, so current is undefined. I made that mistake too, and the error message you get is not very enlightening.

If you use triangular(5.0, 15.0, 10.0, getstream(Table("GlobalTable1"))) then it should work. If you don't want to clutter your code and hardcode the table name everywhere, you could also reserve a specific stream, say 42, and use that: triangular(5.0, 15.0, 10.0, 42).

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Marc K Mischa Spelt commented · Aug 01, 2019 at 12:30 PM

Thank you Mischa. I knew there had to be a simpler way of getting is done.

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