The determinant's length, and the bound that decides how many primes to use before any of them is chosen
At its defaults it draws the determinant's length, and the bound that decides how many primes to use before any of them is chosen. Solid: Hadamard's bound on |det A|, the product of the row 2-norms, in bits. Dotted: the determinant's actual length. The bound is what a modular determinant budgets against — at n = 10 the random family needs 42 bits, which is 2 word-sized primes at 26 bits each, and that count is fixed before the first residue is computed. On a Sylvester Hadamard matrix of order 8 the bound is 13 bits and the determinant has 13, so the bound is attained rather than merely satisfied. On the unit triangular family the determinant is 1 at every size while the bound grows, which is the gap the budget pays for: a matrix can have a determinant of one and rows that are long.
prime-budget is one function in lib/figures/integer.js —
exact arithmetic — no residual to print, and a cost measured in the length of the numbers. Everything below came out of it during this build, at
arguments taken from the essays rather than invented for this page. A figure here is the
figure a reader meets in an essay, and if the generator changes, this page changes with it.
At its defaults
Drawn even though every essay passes arguments — which on this site is every essay, at 100% of placements since the standard pass. A default nothing exercises is a trap for the next essay to call this with none, and this is the page where a default that has drifted from the figures around it becomes visible.
Solid: Hadamard's bound on |det A|, the product of the row 2-norms, in bits. Dotted: the determinant's actual length. The bound is what a modular determinant budgets against — at n = 10 the random family needs 42 bits, which is 2 word-sized primes at 26 bits each, and that count is fixed before the first residue is computed. On a Sylvester Hadamard matrix of order 8 the bound is 13 bits and the determinant has 13, so the bound is attained rather than merely satisfied. On the unit triangular family the determinant is 1 at every size while the bound grows, which is the gap the budget pays for: a matrix can have a determinant of one and rows that are long.
upTo: 11
The arguments are the ones How many primes the answer needs passes. A value nobody placed would be a picture no essay asked for and no claim was ever checked against.
Solid: Hadamard's bound on |det A|, the product of the row 2-norms, in bits. Dotted: the determinant's actual length. The bound is what a modular determinant budgets against — at n = 11 the random family needs 47 bits, which is 2 word-sized primes at 26 bits each, and that count is fixed before the first residue is computed. On a Sylvester Hadamard matrix of order 8 the bound is 13 bits and the determinant has 13, so the bound is attained rather than merely satisfied. On the unit triangular family the determinant is 1 at every size while the bound grows, which is the gap the budget pays for: a matrix can have a determinant of one and rows that are long.
upTo: 5
The arguments are the ones How many primes the answer needs passes. A value nobody placed would be a picture no essay asked for and no claim was ever checked against.
Solid: Hadamard's bound on |det A|, the product of the row 2-norms, in bits. Dotted: the determinant's actual length. The bound is what a modular determinant budgets against — at n = 5 the random family needs 18 bits, which is 1 word-sized prime at 26 bits each, and that count is fixed before the first residue is computed. On a Sylvester Hadamard matrix of order 8 the bound is 13 bits and the determinant has 13, so the bound is attained rather than merely satisfied. On the unit triangular family the determinant is 1 at every size while the bound grows, which is the gap the budget pays for: a matrix can have a determinant of one and rows that are long.
upTo: 13
The arguments are the ones How many primes the answer needs passes. A value nobody placed would be a picture no essay asked for and no claim was ever checked against.
Solid: Hadamard's bound on |det A|, the product of the row 2-norms, in bits. Dotted: the determinant's actual length. The bound is what a modular determinant budgets against — at n = 13 the random family needs 56 bits, which is 3 word-sized primes at 26 bits each, and that count is fixed before the first residue is computed. On a Sylvester Hadamard matrix of order 8 the bound is 13 bits and the determinant has 13, so the bound is attained rather than merely satisfied. On the unit triangular family the determinant is 1 at every size while the bound grows, which is the gap the budget pays for: a matrix can have a determinant of one and rows that are long.
upTo: 9
The arguments are the ones How many primes the answer needs passes. A value nobody placed would be a picture no essay asked for and no claim was ever checked against.
Solid: Hadamard's bound on |det A|, the product of the row 2-norms, in bits. Dotted: the determinant's actual length. The bound is what a modular determinant budgets against — at n = 9 the random family needs 37 bits, which is 2 word-sized primes at 26 bits each, and that count is fixed before the first residue is computed. On a Sylvester Hadamard matrix of order 8 the bound is 13 bits and the determinant has 13, so the bound is attained rather than merely satisfied. On the unit triangular family the determinant is 1 at every size while the bound grows, which is the gap the budget pays for: a matrix can have a determinant of one and rows that are long.
upTo: 8
The arguments are the ones How many primes the answer needs passes. A value nobody placed would be a picture no essay asked for and no claim was ever checked against.
Solid: Hadamard's bound on |det A|, the product of the row 2-norms, in bits. Dotted: the determinant's actual length. The bound is what a modular determinant budgets against — at n = 8 the random family needs 32 bits, which is 2 word-sized primes at 26 bits each, and that count is fixed before the first residue is computed. On a Sylvester Hadamard matrix of order 8 the bound is 13 bits and the determinant has 13, so the bound is attained rather than merely satisfied. On the unit triangular family the determinant is 1 at every size while the bound grows, which is the gap the budget pays for: a matrix can have a determinant of one and rows that are long.
What it checked while drawing
Every figure above checked its own claims on the way to being drawn, and a claim that failed
would have stopped the picture rather than shipped a wrong one. Those checks used to leave
no trace at all: a passing one returned true and the only evidence the figure had
checked anything was that nothing crashed. The list below is what they actually said, collected
by running this generator with an observer installed — not a description of
what it is believed to check.
7 distinct claims across 6 sets of arguments, grouped below by shape — because most of them are one sentence with a different number in it, and how many separate times that sentence was put to the test is the informative part.
a range of sizes
a Sylvester Hadamard order, a power of two
and is attained on a Hadamard matrix, so it is not loose by construction
enough primes for Hadamard's bound on this determinant
every Bareiss division is exact
Hadamard's bound holds on every family drawn
the assertion refuses a counterexample
Against the rule
The rule does not apply to it. It factorises nothing, so there is no residual it could be withholding. That is worth stating rather than leaving blank: a site that reported the rule as satisfied by every generator would be counting mostly generators the rule never reached.
Across the library: the rule bites on 217
of 397 generators —
199 print a residual and
18 are exempt with a published reason;
180 factorise nothing.
Read from lib/residual-rule.js, which is the same body the gate enforces from,
and the gate's last check fails the build if this page and it disagree about any generator.
Where it is called
Changing this generator changes every figure on this list. That is what makes the list worth publishing rather than keeping in a check script.