Numbers stored against the number of indices, at n = 20 and rank 4: the tensor, its core, and a train
At its defaults it draws numbers stored against the number of indices, at n = 20 and rank 4: the tensor, its core, and a train. The tensor is n^d, which at d = 20 is 1.05·10²⁶. A Tucker representation of it is r^d + d·n·r — the core is still exponential in d, so at rank 4 it is 1.1·10¹², smaller than the tensor by 9.54·10¹³ and still unstorable. A train is (d − 2)nr² + 2nr, which is 5,920 — linear in d. The three lines are the field's whole argument: fixing the definition of the decomposition does not fix the size of what it returns, and the second fix is the same projection cut in a different place.
tucker-storage is one function in lib/figures/hosvd.js —
the higher-order svd — d matrix decompositions, and a core that cannot be diagonal. 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.
The tensor is n^d, which at d = 20 is 1.05·10²⁶. A Tucker representation of it is r^d + d·n·r — the core is still exponential in d, so at rank 4 it is 1.1·10¹², smaller than the tensor by 9.54·10¹³ and still unstorable. A train is (d − 2)nr² + 2nr, which is 5,920 — linear in d. The three lines are the field's whole argument: fixing the definition of the decomposition does not fix the size of what it returns, and the second fix is the same projection cut in a different place.
r: 4
The arguments are the ones A compression of 10¹⁴ that still does not fit passes. A value nobody placed would be a picture no essay asked for and no claim was ever checked against.
The tensor is n^d, which at d = 20 is 1.05·10²⁶. A Tucker representation of it is r^d + d·n·r — the core is still exponential in d, so at rank 4 it is 1.1·10¹², smaller than the tensor by 9.54·10¹³ and still unstorable. A train is (d − 2)nr² + 2nr, which is 5,920 — linear in d. The three lines are the field's whole argument: fixing the definition of the decomposition does not fix the size of what it returns, and the second fix is the same projection cut in a different place.
r: 6
The arguments are the ones A compression of 10¹⁴ that still does not fit passes. A value nobody placed would be a picture no essay asked for and no claim was ever checked against.
The tensor is n^d, which at d = 20 is 1.05·10²⁶. A Tucker representation of it is r^d + d·n·r — the core is still exponential in d, so at rank 6 it is 3.66·10¹⁵, smaller than the tensor by 2.87·10¹⁰ and still unstorable. A train is (d − 2)nr² + 2nr, which is 13,200 — linear in d. The three lines are the field's whole argument: fixing the definition of the decomposition does not fix the size of what it returns, and the second fix is the same projection cut in a different place.
r: 2
The arguments are the ones A compression of 10¹⁴ that still does not fit passes. A value nobody placed would be a picture no essay asked for and no claim was ever checked against.
The tensor is n^d, which at d = 20 is 1.05·10²⁶. A Tucker representation of it is r^d + d·n·r — the core is still exponential in d, so at rank 2 it is 1.05·10⁶, smaller than the tensor by 9.99·10¹⁹ and still unstorable. A train is (d − 2)nr² + 2nr, which is 1,520 — linear in d. The three lines are the field's whole argument: fixing the definition of the decomposition does not fix the size of what it returns, and the second fix is the same projection cut in a different place.
r: 3
The arguments are the ones A compression of 10¹⁴ that still does not fit passes. A value nobody placed would be a picture no essay asked for and no claim was ever checked against.
The tensor is n^d, which at d = 20 is 1.05·10²⁶. A Tucker representation of it is r^d + d·n·r — the core is still exponential in d, so at rank 3 it is 3.49·10⁹, smaller than the tensor by 3.01·10¹⁶ and still unstorable. A train is (d − 2)nr² + 2nr, which is 3,360 — linear in d. The three lines are the field's whole argument: fixing the definition of the decomposition does not fix the size of what it returns, and the second fix is the same projection cut in a different place.
r: 5
The arguments are the ones A compression of 10¹⁴ that still does not fit passes. A value nobody placed would be a picture no essay asked for and no claim was ever checked against.
The tensor is n^d, which at d = 20 is 1.05·10²⁶. A Tucker representation of it is r^d + d·n·r — the core is still exponential in d, so at rank 5 it is 9.54·10¹³, smaller than the tensor by 1.1·10¹² and still unstorable. A train is (d − 2)nr² + 2nr, which is 9,200 — linear in d. The three lines are the field's whole argument: fixing the definition of the decomposition does not fix the size of what it returns, and the second fix is the same projection cut in a different place.
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.
3 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 rank the storage is counted at
and at two indices they are the same object
the core outgrows the train
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.
A compression of 10¹⁴ that still does not fit
A Tucker core of a twenty-index array at rank four is 1.1·10¹² numbers against the tensor's 1.05·10²⁶ — a compression by a factor of 9.5·10¹³ that is still nearly nine terabytes. The ratio is not the verdict. The verdict is a ceiling, and the ceiling is a number of indices.
When the index is a tupleA decomposition made only of SVDs
Everything the definition of tensor rank loses comes back if the SVD's algorithm is carried across instead of its definition — take the leading left singular subspace of every unfolding and project onto all of them. It exists, it costs d matrix decompositions, and its error is within √d of the best there is.