If-then-else issue in Rust

[Julen Bernabé]

Hi all,

I'm trying to compare two SecretI64 numbers and want to do some computations if the first number is greater than the second one. Algorithmically my code can be expressed as follows:

let a = SecretI64::from(5);

let b = SecretI64::from(4);

if a.gt(b) {

       println!("Hello World!");

}

I know that SecretI64 comparisons output a SecretBit, and if-then-else branches can only be expressed with conditions involving i64 numbers. For that reason, I considered the following variable changes:

let sbit = SecretBit::from(true);   // This would be replaced by a.gt(b)

let s_i64_bit = SecretI64::from(sbit);

let s_mp_bit = SecretModp::from(s_i64_bit);

let c_mp_bit = s_mp_bit.reveal();

let i_64_bit = i64::from(c_mp_bit);

As a consequence, I have turned the SecretBit into an i64 integer with value 0 (false) or 1 (true). Then I only have to write the following to branch my code:

if i_64_bit == 1 {

      // code if true

}

The issue is that the compilation of this program does not output any error, but ends without generating the needed .bc and .sch files. I attach a screenshot of the compilation. What can be wrong?

Thanks beforehand! Regards,

Julen

[Nigel Smart]

Hi

Sorry for taking so long to get back to you.

Try this...

let sbit = SecretBit::from(true); // This would be replaced by
a.gt(b)

let ibit = sbit.reveal();

if ibit {
println!("This is true");
}
else {
println!("This is false");
}

No idea why you get the weird compilation behaviour
on your code

Nigel

On 02/02/2022 15:52, Julen Bernabé wrote:
> Hi all,
>
> I'm trying to compare two SecretI64 numbers and want to do some
> computations if the first number is greater than the second one.
> Algorithmically my code can be expressed as follows:
>

> *let a = SecretI64::from(5);*
> *let b = SecretI64::from(4);*
> *if a.gt(b) {*
> *println!("Hello World!");*
> *}*
> *
> *

> I know that SecretI64 comparisons output a SecretBit, and if-then-else
> branches can only be expressed with conditions involving i64 numbers.
> For that reason, I considered the following variable changes:
>

> *let sbit = SecretBit::from(true);   // This would be replaced by a.gt(b)*
> *let s_i64_bit = SecretI64::from(sbit);*
> *let s_mp_bit = SecretModp::from(s_i64_bit);*
> *let c_mp_bit = s_mp_bit.reveal();*
> *let i_64_bit = i64::from(c_mp_bit);*
> *
> *

> As a consequence, I have turned the SecretBit into an i64 integer with
> value 0 (false) or 1 (true). Then I only have to write the following to
> branch my code:
>

> *if i_64_bit == 1 {*
> *      // code if true*
> *}*
> *
> *

> The issue is that the compilation of this program does not output any
> error, but ends without generating the needed .bc and .sch files. I
> attach a screenshot of the compilation. What can be wrong?
>
> Thanks beforehand! Regards,
>
> Julen
>

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