Updated README for BigNum lib #85
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jzaki
approved these changes
Dec 24, 2024
| pub limbs: [Field; N], | ||
| } | ||
| ``` | ||
| - `N` is the number of limbs needed to represent the number. Each limb is a `Field`, which contains max 120 bits (a field has 254 bits) |
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I found it confusing when reading "contains max 120 bits" and "has 254 bits".
Suggested change
| - `N` is the number of limbs needed to represent the number. Each limb is a `Field`, which contains max 120 bits (a field has 254 bits) | |
| - `N` is the number of limbs needed to represent the number. Each limb is at most 120 bits, stored in a `Field` (254 bits) |
And if useful could add reasoning "enables limb multiplication without overflow" (if that is indeed the case)
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| ## `RuntimeBigNum` | ||
| - `redc_param` is equal to `(1 << (2 * Params::modulus_bits())) / modulus` . This must be computed outside of the circuit and provided either as a private witness or hardcoded constant. (computing it via an unconstrained function would be very expensive until noir witness computation times improve) |
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Did you mean "constrained"?
Suggested change
| - `redc_param` is equal to `(1 << (2 * Params::modulus_bits())) / modulus` . This must be computed outside of the circuit and provided either as a private witness or hardcoded constant. (computing it via an unconstrained function would be very expensive until noir witness computation times improve) | |
| - `redc_param` is equal to `(1 << (2 * Params::modulus_bits())) / modulus` . This must be computed outside of the circuit and provided either as a private witness or hardcoded constant. (computing it via a constrained function would be very expensive until noir witness computation times improve) |
| let one: My_RBN = RuntimeBigNum::from_array(params, [1, 0, 0]); | ||
| let two: My_RBN = RuntimeBigNum::from_array(params, [2, 0, 0]); | ||
| let three: My_RBN = RuntimeBigNum::from_array(params, [3, 0, 0]); | ||
| The methods that are available on the types `BigNum` and `RuntimeBigNum` are almost the same. Thsi section discusses the methods and talks about "bignum" to indicate both types. |
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Suggested change
| The methods that are available on the types `BigNum` and `RuntimeBigNum` are almost the same. Thsi section discusses the methods and talks about "bignum" to indicate both types. | |
| The methods that are available on the types `BigNum` and `RuntimeBigNum` are almost the same. This section discusses these methods and uses "bignum" to indicate both types. |
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| `modulus` represents the BigNum modulus, encoded as an array of `Field` elements that each encode 120 bits of the modulus. The first array element represents the least significant 120 bits. | ||
| ## Custom or predefined parameter set |
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Previously I've noticed "parameterset" as one word, and didn't know if it was intentional?
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| TODO: the paramgen tool is not up to date for `BigNum` version >= `0.4`, an issue has been created for this [here](https://github.com/noir-lang/noir-bignum-paramgen/issues/4). This section should be adjusted after this fix. | ||
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| The easiest way to generate everything you need for a parameter set is to use [this tool](https://github.com/noir-lang/noir-bignum-paramgen). |
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In most places I've seen "parameterset" as one word, is that intentional? In a couple of places it is "parameter set".
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Description
Replacement of previously added documentation here as requested by @jzaki.
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cargo fmton default settings.