# Silence parser warnings about integer division

**URL:** <https://discourse.mc-stan.org/t/silence-parser-warnings-about-integer-division/7716>\
**Category:** General\
**Created:** [February 14, 2019, 10:50pm UTC](https://discourse.mc-stan.org/t/silence-parser-warnings-about-integer-division/7716 "2019-02-14T22:50:55Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![paul.buerkner](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/paul.buerkner/32/3303_2.png) [@paul.buerkner](https://discourse.mc-stan.org/u/paul.buerkner)\
**Post date:** [February 14, 2019, 10:50pm UTC](https://discourse.mc-stan.org/t/silence-parser-warnings-about-integer-division/7716/1 "2019-02-14T22:50:55Z")

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For use in brms, I want to implement the following Stan code:

```
for (k in 1:nresp) {
  for (j in 1:(k - 1)) {
    cor[(k - 1) * (k - 2) / 2 + j] = Cor[j, k];
  }
}

```

to extract the elements of a matrix above the diagonal.

Not surprisingly, this triggers warnings about integer division.  
I know that the integer division will be valid in this case and want to silence the parser  
about this issue. Is there any way to achieve this or to extract the  
upper diagonal elements of a matrix in any other way?

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<div class="post-metadata">

**Author:** ![bgoodri](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/bgoodri/32/4451_2.png) [@bgoodri](https://discourse.mc-stan.org/u/bgoodri)\
**Post date:** [February 14, 2019, 10:52pm UTC](https://discourse.mc-stan.org/t/silence-parser-warnings-about-integer-division/7716/2 "2019-02-14T22:52:39Z")

</div>

`cor[choose(k - 1, 2) + j] = Cor[j,k];`

---

<div class="post-metadata">

**Author:** ![paul.buerkner](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/paul.buerkner/32/3303_2.png) [@paul.buerkner](https://discourse.mc-stan.org/u/paul.buerkner)\
**Post date:** [February 14, 2019, 10:53pm UTC](https://discourse.mc-stan.org/t/silence-parser-warnings-about-integer-division/7716/3 "2019-02-14T22:53:29Z")

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Thanks a lot Ben!