UUlpNacre
AI coding workspace

Finite binary64 ULP distance

UlpNacre is a Windows workspace for AI-assisted review of floating-point representation. Open the project and discuss adjacent binary64 values with a compatible model while keeping numerical accuracy claims under review.

● ● ●UlpNacre●
A concrete starting point · Finite binary64 ULP distance ×
import math, struct

def ulp_distance(a, b):
    if any(type(x) is not float or not math.isfinite(x) for x in (a, b)):
        raise ValueError("ulp.finite")
    def key(value):
        bits = struct.unpack(">Q", struct.pack(">d", value))[0]
        magnitude = bits & ((1 << 63)-1)
        return (1 << 63)-magnitude if bits >> 63 else (1 << 63)+magnitude
    return abs(key(a)-key(b))
✳Finite binary64 ULP distance
✓ ChangesReview before applying ↗
Illustrative workspace
Connection
Base URL, credentials and a reachable server.
Project
Test adjacent subnormals and both signs, rejecting integers, infinities and NaN without interpreting the result as relative error.
Review before applying
Compare actual behavior with the expected result. If a check fails, investigate it before applying more changes.
Workflows

Finite binary64 ULP distance

Workflows ↗
A concrete starting point
import math, struct

def ulp_distance(a, b):
    if any(type(x) is not float or not math.isfinite(x) for x in (a, b)):
        raise ValueError("ulp.finite")
    def key(value):
        bits = struct.unpack(">Q", struct.pack(">d", value))[0]
        magnitude = bits & ((1 << 63)-1)
        return (1 << 63)-magnitude if bits >> 63 else (1 << 63)+magnitude
    return abs(key(a)-key(b))
AI coding workspace

Give a numerical discrepancy the right comparison rule

Two numerical outputs can print alike while differing in their underlying representation. UlpNacre gives you a Windows AI coding workspace for investigating whether that difference matters to your application. Bring the actual inputs, computation and comparison that triggered the concern. Ask the assistant to inspect how values are produced and judged before replacing an equality check with a different rule.

The floating-point representation-distance example offers one possible task. You could examine finite inputs and signed zero, then discuss how a distance result should inform a test or diagnostic. Keep the application's tolerance decision separate from the measurement itself. The source example is Python; the domain name does not establish a PHP-specific debugger or make its assumptions valid for every numerical runtime.

Use a supported OpenAI-compatible or Anthropic endpoint to select an available abliterated AI model, with credentials where needed. Context, tools and restrictions depend on that model and server. Review the proposed comparison code and run it against representative values relevant to your application. A separate local model server covers inference, while connected tools may still operate through external services.

Investigating representation differences

Should every small representation distance count as equal?

That is an application requirement, not a conclusion supplied by the measurement. Consider how the value is used and define an acceptable comparison rule. Ask the proposal to explain its limits and test values near the decisions your software actually makes.

Why include the computation that produced the values?

The origin can explain why values differ and whether the discrepancy is expected. Inspect conversions and operations before changing the final comparison. A new tolerance may hide a defect elsewhere if the calculation path remains unexplained.

Can the example compare every possible numeric input?

No. Its stated contract accepts finite floating-point inputs, and other values need an explicit policy. Keep rejected inputs visible in the review rather than assuming a representation-distance helper covers every numeric type or exceptional value.

What should I verify when moving the idea to another runtime?

Check the runtime's numeric representation, conversion behavior and available operations. Recreate relevant boundary cases in that environment. The supplied Python example is a starting point for investigation, not evidence that an untested translation has identical behavior.

Get the Windows app ↗

UlpNacre · Updated 2026-10-25