SSM-Clock Stamp – Float Parity Across Implementations (5.12)

Objective. Confirm that different tools/languages print identical theta_deg strings when they follow the same fixed-digit, IEEE-754 binary64 round-half-to-even rule — fully offline, plain ASCII.

Deterministic rules (must)

  • UTC → angle only:
    wrap360(x) = x - 360*floor(x/360)
    theta_deg = wrap360( (unix_seconds / 86400) * 360 )
    rasi_idx = floor(theta_deg / 30)
  • Fixed print: theta_deg rendered with exactly theta_prec fractional digits (default 5) using half-to-even; decimal point is ..
  • Compare as strings; do not rely on float tolerances for acceptance.

Test plan (copy-ready)

  1. Pick probe times (UTC, seconds only; no subseconds; leap second :60 forbidden):
    • Exact minute: YYYY-MM-DDTHH:MM:00Z
    • Near day boundary: ...T23:59:59Z and +1s
    • Near sector cusps: times s.t. theta_deg ≈ 30*k
    • Half-way rounding probes where the next discarded digit is exactly 5
  2. In each implementation, compute and print:
    • unix_seconds = seconds_since_1970_UTC(iso_utc)
    • theta_deg = wrap360( (unix_seconds / 86400) * 360 )
    • theta_str = print_fixed(theta_deg, theta_prec, half_to_even=True)
    • rasi_idx = floor(theta_deg / 30)
  3. Compare outputs across tools:
    • Require identical theta_str and identical rasi_idx.

Expected

theta_str(tool_A) == theta_str(tool_B) == ...   # exact string equality
rasi_idx(tool_A) == rasi_idx(tool_B) == ...
CLOCK_OK=true

Half-to-even sanity probes (examples)

  • Choose iso_utc where (unix_seconds / 86400) * 360 produces a decimal tail like ...x5... at the (theta_prec+1)th digit; verify the final emitted digit is even when tied.

Common pitfalls (avoid)

  • Using locale formatting (, as decimal) or trimming trailing zeros.
  • Printing with more/fewer than theta_prec digits.
  • Relying on extended precision during formatting (must be binary64).
  • Parsing/printing non-UTC (offsets) or with subseconds.

Why this matters
The Shunyaya Symbolic Mathematical Clock Stamp requires string-equal theta_deg to guarantee cross-tool reproducibility and identical anchors.

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