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Add randlapack.cqrrpt and randlapack.cqrrt next to randlapack.bqrrp, for
tall matrices (m >= d_factor*n):
- CQRRPT (rank-revealing QR with column pivoting): [Q, R, J] with the rank
detected by CQRRPT as the inner dimension of Q and R; 'eps', 'd_factor'
and 'state' options. Taken from the unmerged bindings-wave1 branch, with
`rank` reset before the call (CQRRPT returns early on an all-zero input
without setting it) and the J-zeroing comment updated (RandLAPACK now
zeroes J itself; the MEX keeps doing it for older installs).
- CQRRT (unpivoted Cholesky QR for full-rank input): [Q, R] like
qr(A, 0), with Q factored in place into its output buffer; R = cqrrt(A)
uses CQRRT's R-only mode and forms no Q. CQRRT does not detect rank: a
rank-deficient input usually completes with a numerically singular R
(documented and tested); an exactly singular sketch or a Cholesky failure
is reported as randlapack:cqrrt_mex:breakdown, pointing at cqrrpt and
bqrrp.
- The RNG-state helpers move to +randlapack/private and bqrrp.m uses them.
- matlab/CMakeLists.txt: randlapack_add_mex(name) applies the per-target
setup (include dirs, output dir, static libstdc++ on GNU, Windows DLL
staging and libiomp5md.dll removal, MSVC OpenMP linkage) to all three
targets; bqrrp_mex's flags.make and link.txt are unchanged on Linux.
- All three MEX files: errors raised by the MEX keep their identifier.
feval("error") throws matlab::engine::MATLABExecutionException, which
derives from matlab::engine::Exception and std::exception but not from
matlab::Exception, so the old `catch (const matlab::Exception&)` never
matched and the std::exception handler re-raised it as ...:StdError. A
`catch (const matlab::engine::Exception&) { throw; }` now comes first.
- Tests, demos and README for both drivers. The CQRRPT demo compares
against qr(A, 'econ', 'vector') after a warm-up call (it used to compare
against a full QR with an m-by-m Q). Help texts and README say "matches
qr(A, 'econ', 'vector')" for bqrrp and cqrrpt.
Verified on Linux (GCC 15.2, MATLAB R2026a, RandLAPACK main): test_bqrrp,
test_cqrrpt and test_cqrrt pass, including rank detection, the all-zero
and breakdown error IDs, R-only vs [Q, R] agreement, a rank-deficient input
completing with a singular R, and a cond(A) = 1e10 input; CQRRT on
50000x500 matches qr(A, 0)'s R to 2e-15 (2.9x faster), CQRRPT on 20000x200
is 8.8x faster than qr(A, 'econ', 'vector'). On Windows (MSVC 19.44, MATLAB R2026a, RandLAPACK main installed
with install.ps1, threaded oneMKL): the three MEX files build with the README
command, import only MATLAB's libiomp5md for OpenMP, and all three test
suites pass with KMP_DUPLICATE_LIB_OK unset.
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Summary
MATLAB bindings for RandLAPACK's dense CQRRPT and CQRRT, next to BQRRP. Both are sketch-and-precondition QR factorizations for tall matrices (
m >= d_factor*n): CQRRPT pivots and reveals the rank, CQRRT is unpivoted Cholesky QR for full-rank input and also has an R-only mode. RSVD and the Python bindings from #5 are not included.Changes
randlapack.cqrrpt(cqrrpt_mex.cc,cqrrpt.m, test, demo), taken from Wave 1: bind RSVD and CQRRPT in MATLAB and Python #5:[Q, R, J] = randlapack.cqrrpt(A)with the detected rank as the inner dimension of Q and R; options'eps','d_factor','state'. Changes from Wave 1: bind RSVD and CQRRPT in MATLAB and Python #5:rankis reset before the call, since CQRRPT returns early on an all-zero input without setting it (now a clear zero-rank error, with a test); the J-zeroing comment reflects that RandLAPACK now zeroes J itself.randlapack.cqrrt(cqrrt_mex.cc,cqrrt.m, test, demo):[Q, R] = randlapack.cqrrt(A)likeqr(A, 0);R = randlapack.cqrrt(A)uses CQRRT's R-only mode and forms no Q; options'd_factor','state'. CQRRT does not detect rank: a rank-deficient input usually completes with a numerically singular R, which the help says to check for; an exactly singular sketch (e.g. a zero column) or a Cholesky failure raisesrandlapack:cqrrt_mex:breakdown, pointing atcqrrptandbqrrp.+randlapack/private/(from Wave 1: bind RSVD and CQRRPT in MATLAB and Python #5);bqrrp.muses them.matlab/CMakeLists.txt: one function,randlapack_add_mex(name), applies the per-target setup (include dirs, output dir, static libstdc++ on GNU, Windows DLL staging andlibiomp5md.dllremoval, MSVC OpenMP linkage) to all three MEX targets;bqrrp_mex's build flags are unchanged. On Windows the targets link one after another, because each stages the same backend DLLs into the same directory and parallel copies can collide.feval("error")throwsmatlab::engine::MATLABExecutionException, which does not derive frommatlab::Exception, so the old pass-through handler never matched and thestd::exceptionhandler re-raised the error as...:StdError; acatch (const matlab::engine::Exception&) { throw; }now comes first. This also affectedbqrrp_mex.qr(A, 'econ', 'vector')after a warm-up call;bqrrp/cqrrpthelp and README say they matchqr(A, 'econ', 'vector').