Incorrect Multiply Result?

[Tom321]

I'm doing the following, and received the wrong value. Is there something I'm missing?

[Jewsus]

Why is this incorrect?

anything x 0 = 0 and -0 = 0

[m3rl3n]

To prove that -0 is equal to 0, add an increment by 1 after the multiply and before your indicator.  The math is correct, it may just look wonky.

[Tom321]

I mean it makes sense. The reason why I ask is because problem arises when I try to convert this is an string which now becomes "-0". Doing any comparisons fails immediately. Is there a reason why LV does this, rather than follow -1 * 0 = 0?

[crossrulz · Accepted solution]

Well, there is a sign bit in the IEEE754 specification.  When multiplying, the two sign bits should just be XORed.  -1 has a sign of 1 (negative) while 0 has a sign of 0 (positive).  XOR the values and you get 1 (negative).  This results in -0.

For additional reading: Signed zero

[altenbach]

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@Tom321 wrote:

Doing any comparisons fails immediately.

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Define "fail". If you do the comparison on the numerics, you can see that -0 and 0 are equal as expected.

[crossrulz]

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@altenbach wrote:

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@Tom321 wrote:

Doing any comparisons fails immediately.

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Define "fail". If you do the comparison on the numerics, you can see that -0 and 0 are equal as expected.

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Tom321 did sort of define it.  He stated that he converts to a string and then does comparisons.