Mercurial > octave
view libinterp/corefcn/kron.cc @ 21724:aba2e6293dd8
use "#if ..." consistently instead of "#ifdef" and "#ifndef"
* configure.ac, Doxyfile.in, make_int.cc, Backend.cc, BaseControl.cc,
ButtonControl.cc, Canvas.cc, CheckBoxControl.cc, Container.cc,
ContextMenu.cc, EditControl.cc, Figure.cc, FigureWindow.cc,
GLCanvas.cc, KeyMap.cc, ListBoxControl.cc, Logger.cc, Menu.cc,
MouseModeActionGroup.cc, Object.cc, ObjectFactory.cc,
ObjectProxy.cc, Panel.cc, PopupMenuControl.cc, PushButtonControl.cc,
PushTool.cc, QtHandlesUtils.cc, RadioButtonControl.cc,
SliderControl.cc, TextControl.cc, TextEdit.cc,
ToggleButtonControl.cc, ToggleTool.cc, ToolBar.cc, __init_qt__.cc,
annotation-dialog.cc, gl-select.cc, module.mk, color-picker.cc,
dialog.cc, documentation-dock-widget.cc, files-dock-widget.cc,
find-files-dialog.cc, find-files-model.cc, history-dock-widget.cc,
liboctgui-build-info.in.cc, file-editor-tab.cc, file-editor.cc,
find-dialog.cc, marker.cc, marker.h, octave-qscintilla.cc,
octave-txt-lexer.cc, main-window.cc, octave-cmd.cc,
octave-dock-widget.cc, octave-gui.cc, octave-interpreter.cc,
octave-qt-link.cc, parser.cc, webinfo.cc, resource-manager.cc,
settings-dialog.cc, shortcut-manager.cc, terminal-dock-widget.cc,
thread-manager.cc, welcome-wizard.cc, workspace-model.cc,
workspace-view.cc, build-env.in.cc, Cell.cc, __contourc__.cc,
__dispatch__.cc, __dsearchn__.cc, __ichol__.cc, __ilu__.cc,
__lin_interpn__.cc, __luinc__.cc, __magick_read__.cc,
__pchip_deriv__.cc, __qp__.cc, balance.cc, besselj.cc, betainc.cc,
bitfcns.cc, bsxfun.cc, c-file-ptr-stream.cc, c-file-ptr-stream.h,
cdisplay.c, cdisplay.h, cellfun.cc, coct-hdf5-types.c, colloc.cc,
comment-list.cc, conv2.cc, daspk.cc, dasrt.cc, dassl.cc, data.cc,
debug.cc, defaults.cc, defaults.in.h, defun.cc, det.cc, dirfns.cc,
display.cc, dlmread.cc, dot.cc, dynamic-ld.cc, eig.cc, ellipj.cc,
error.cc, errwarn.cc, event-queue.cc, fft.cc, fft2.cc, fftn.cc,
file-io.cc, filter.cc, find.cc, ft-text-renderer.cc, gammainc.cc,
gcd.cc, getgrent.cc, getpwent.cc, getrusage.cc, givens.cc,
gl-render.cc, gl2ps-print.cc, graphics.cc, gripes.cc, hash.cc,
help.cc, hess.cc, hex2num.cc, input.cc, inv.cc, jit-ir.cc, jit-ir.h,
jit-typeinfo.cc, jit-typeinfo.h, jit-util.cc, jit-util.h, kron.cc,
load-path.cc, load-save.cc, lookup.cc, ls-ascii-helper.cc,
ls-hdf5.cc, ls-mat-ascii.cc, ls-mat4.cc, ls-mat5.cc,
ls-oct-binary.cc, ls-oct-text.cc, ls-oct-text.h, ls-utils.cc,
lsode.cc, lu.cc, mappers.cc, matrix_type.cc, max.cc, mex.cc, mex.h,
mexproto.h, mgorth.cc, nproc.cc, oct-errno.in.cc, oct-fstrm.cc,
oct-hdf5-types.cc, oct-hdf5-types.h, oct-hist.cc, oct-iostrm.cc,
oct-lvalue.cc, oct-map.cc, oct-prcstrm.cc, oct-procbuf.cc,
oct-stdstrm.h, oct-stream.cc, oct-strstrm.cc, oct-tex-lexer.in.ll,
oct-tex-parser.in.yy, octave-link.cc, ordschur.cc, pager.cc,
pinv.cc, pr-output.cc, procstream.cc, profiler.cc, psi.cc,
pt-jit.cc, pt-jit.h, quad.cc, quadcc.cc, qz.cc, rand.cc, rcond.cc,
regexp.cc, schur.cc, sighandlers.cc, sighandlers.h, siglist.c,
siglist.h, sparse-xdiv.cc, sparse-xpow.cc, sparse.cc, spparms.cc,
sqrtm.cc, str2double.cc, strfind.cc, strfns.cc, sub2ind.cc, svd.cc,
sylvester.cc, symtab.cc, syscalls.cc, sysdep.cc, text-renderer.cc,
time.cc, toplev.cc, tril.cc, tsearch.cc, txt-eng.cc, typecast.cc,
urlwrite.cc, utils.cc, variables.cc, xdiv.cc, xgl2ps.c, xnorm.cc,
xpow.cc, zfstream.cc, zfstream.h, __delaunayn__.cc, __eigs__.cc,
__fltk_uigetfile__.cc, __glpk__.cc, __init_fltk__.cc,
__init_gnuplot__.cc, __osmesa_print__.cc, __voronoi__.cc, amd.cc,
audiodevinfo.cc, audioread.cc, ccolamd.cc, chol.cc, colamd.cc,
convhulln.cc, dmperm.cc, fftw.cc, qr.cc, symbfact.cc, symrcm.cc,
liboctinterp-build-info.in.cc, mkbuiltins, mkops, ov-base.cc,
ov-bool-mat.cc, ov-bool-sparse.cc, ov-bool.cc, ov-builtin.cc,
ov-cell.cc, ov-ch-mat.cc, ov-class.cc, ov-classdef.cc, ov-colon.cc,
ov-complex.cc, ov-cs-list.cc, ov-cx-diag.cc, ov-cx-mat.cc,
ov-cx-sparse.cc, ov-dld-fcn.cc, ov-fcn-handle.cc, ov-fcn-inline.cc,
ov-fcn.cc, ov-float.cc, ov-flt-complex.cc, ov-flt-cx-diag.cc,
ov-flt-cx-mat.cc, ov-flt-re-diag.cc, ov-flt-re-mat.cc, ov-int16.cc,
ov-int32.cc, ov-int64.cc, ov-int8.cc, ov-java.cc, ov-lazy-idx.cc,
ov-mex-fcn.cc, ov-null-mat.cc, ov-oncleanup.cc, ov-perm.cc,
ov-range.cc, ov-re-diag.cc, ov-re-mat.cc, ov-re-sparse.cc,
ov-scalar.cc, ov-str-mat.cc, ov-struct.cc, ov-typeinfo.cc,
ov-uint16.cc, ov-uint32.cc, ov-uint64.cc, ov-uint8.cc,
ov-usr-fcn.cc, ov-usr-fcn.h, ov.cc, ovl.cc, octave.cc, octave.h,
op-b-b.cc, op-b-bm.cc, op-b-sbm.cc, op-bm-b.cc, op-bm-bm.cc,
op-bm-sbm.cc, op-cdm-cdm.cc, op-cdm-cm.cc, op-cdm-dm.cc,
op-cdm-m.cc, op-cell.cc, op-chm.cc, op-class.cc, op-cm-cdm.cc,
op-cm-cm.cc, op-cm-cs.cc, op-cm-dm.cc, op-cm-m.cc, op-cm-s.cc,
op-cm-scm.cc, op-cm-sm.cc, op-cs-cm.cc, op-cs-cs.cc, op-cs-m.cc,
op-cs-s.cc, op-cs-scm.cc, op-cs-sm.cc, op-dm-cdm.cc, op-dm-cm.cc,
op-dm-dm.cc, op-dm-m.cc, op-dm-scm.cc, op-dm-sm.cc,
op-dm-template.cc, op-dms-template.cc, op-double-conv.cc,
op-fcdm-fcdm.cc, op-fcdm-fcm.cc, op-fcdm-fdm.cc, op-fcdm-fm.cc,
op-fcm-fcdm.cc, op-fcm-fcm.cc, op-fcm-fcs.cc, op-fcm-fdm.cc,
op-fcm-fm.cc, op-fcm-fs.cc, op-fcn.cc, op-fcs-fcm.cc, op-fcs-fcs.cc,
op-fcs-fm.cc, op-fcs-fs.cc, op-fdm-fcdm.cc, op-fdm-fcm.cc,
op-fdm-fdm.cc, op-fdm-fm.cc, op-float-conv.cc, op-fm-fcdm.cc,
op-fm-fcm.cc, op-fm-fcs.cc, op-fm-fdm.cc, op-fm-fm.cc, op-fm-fs.cc,
op-fs-fcm.cc, op-fs-fcs.cc, op-fs-fm.cc, op-fs-fs.cc, op-i16-i16.cc,
op-i32-i32.cc, op-i64-i64.cc, op-i8-i8.cc, op-int-concat.cc,
op-int-conv.cc, op-m-cdm.cc, op-m-cm.cc, op-m-cs.cc, op-m-dm.cc,
op-m-m.cc, op-m-s.cc, op-m-scm.cc, op-m-sm.cc, op-pm-pm.cc,
op-pm-scm.cc, op-pm-sm.cc, op-pm-template.cc, op-range.cc,
op-s-cm.cc, op-s-cs.cc, op-s-m.cc, op-s-s.cc, op-s-scm.cc,
op-s-sm.cc, op-sbm-b.cc, op-sbm-bm.cc, op-sbm-sbm.cc, op-scm-cm.cc,
op-scm-cs.cc, op-scm-m.cc, op-scm-s.cc, op-scm-scm.cc, op-scm-sm.cc,
op-sm-cm.cc, op-sm-cs.cc, op-sm-m.cc, op-sm-s.cc, op-sm-scm.cc,
op-sm-sm.cc, op-str-m.cc, op-str-s.cc, op-str-str.cc, op-struct.cc,
op-ui16-ui16.cc, op-ui32-ui32.cc, op-ui64-ui64.cc, op-ui8-ui8.cc,
lex.ll, oct-parse.in.yy, pt-arg-list.cc, pt-array-list.cc,
pt-assign.cc, pt-binop.cc, pt-bp.cc, pt-cbinop.cc, pt-cell.cc,
pt-check.cc, pt-classdef.cc, pt-cmd.cc, pt-colon.cc, pt-const.cc,
pt-decl.cc, pt-eval.cc, pt-except.cc, pt-exp.cc, pt-fcn-handle.cc,
pt-funcall.cc, pt-id.cc, pt-idx.cc, pt-jump.cc, pt-loop.cc,
pt-loop.h, pt-mat.cc, pt-misc.cc, pt-pr-code.cc, pt-select.cc,
pt-stmt.cc, pt-unop.cc, pt.cc, token.cc, Array-jit.cc, Array-tc.cc,
version.cc, Array-C.cc, Array-b.cc, Array-ch.cc, Array-d.cc,
Array-f.cc, Array-fC.cc, Array-i.cc, Array-idx-vec.cc, Array-s.cc,
Array-str.cc, Array-util.cc, Array-voidp.cc, Array.cc,
CColVector.cc, CDiagMatrix.cc, CMatrix.cc, CNDArray.cc,
CRowVector.cc, CSparse.cc, MArray-C.cc, MArray-d.cc, MArray-f.cc,
MArray-fC.cc, MArray-i.cc, MArray-s.cc, MSparse-C.cc, MSparse-d.cc,
MatrixType.cc, PermMatrix.cc, Range.cc, Sparse-C.cc, Sparse-b.cc,
Sparse-d.cc, boolMatrix.cc, boolNDArray.cc, boolSparse.cc,
chMatrix.cc, chNDArray.cc, dColVector.cc, dDiagMatrix.cc,
dMatrix.cc, dNDArray.cc, dRowVector.cc, dSparse.cc, dim-vector.cc,
dim-vector.h, fCColVector.cc, fCDiagMatrix.cc, fCMatrix.cc,
fCNDArray.cc, fCRowVector.cc, fColVector.cc, fDiagMatrix.cc,
fMatrix.cc, fNDArray.cc, fRowVector.cc, idx-vector.cc,
int16NDArray.cc, int32NDArray.cc, int64NDArray.cc, int8NDArray.cc,
uint16NDArray.cc, uint32NDArray.cc, uint64NDArray.cc,
uint8NDArray.cc, Faddeeva.cc, blaswrap.c, cquit.c, f77-extern.cc,
f77-fcn.c, f77-fcn.h, lo-error.c, lo-error.h, quit.cc, quit.h,
liboctave-build-info.in.cc, CollocWt.cc, DASPK.cc, DASRT.cc,
DASSL.cc, EIG.cc, LSODE.cc, ODES.cc, Quad.cc, aepbalance.cc,
chol.cc, eigs-base.cc, fEIG.cc, gepbalance.cc, hess.cc,
lo-mappers.cc, lo-specfun.cc, lu.cc, oct-convn.cc, oct-fftw.cc,
oct-norm.cc, oct-rand.cc, oct-spparms.cc, qr.cc, qrp.cc,
randmtzig.cc, randpoisson.cc, schur.cc, sparse-chol.cc,
sparse-dmsolve.cc, sparse-lu.cc, sparse-qr.cc, svd.cc, mk-ops.awk,
mx-defs.h, dir-ops.cc, file-ops.cc, file-stat.cc, lo-sysdep.cc,
mach-info.cc, oct-env.cc, oct-group.cc, oct-passwd.cc,
oct-syscalls.cc, oct-time.cc, oct-uname.cc, pathlen.h, syswait.h,
cmd-edit.cc, cmd-hist.cc, data-conv.cc, f2c-main.c, glob-match.cc,
kpse.cc, lo-array-errwarn.cc, lo-array-gripes.cc, lo-cutils.c,
lo-cutils.h, lo-ieee.cc, lo-ieee.h, lo-regexp.cc, lo-utils.cc,
oct-base64.cc, oct-glob.cc, oct-inttypes.cc, oct-inttypes.h,
oct-locbuf.cc, oct-mutex.cc, oct-rl-edit.c, oct-rl-edit.h,
oct-rl-hist.c, oct-rl-hist.h, oct-shlib.cc, oct-sort.cc,
pathsearch.cc, singleton-cleanup.cc, sparse-sort.cc, sparse-util.cc,
statdefs.h, str-vec.cc, unwind-prot.cc, url-transfer.cc,
acinclude.m4, display-available.c, display-available.h, main-cli.cc,
main-gui.cc, main.in.cc, mkoctfile.in.cc, octave-build-info.in.cc,
octave-config.in.cc, shared-fcns.h:
Use "#if ..." consistently instead of "#ifdef" and "#ifndef".
author | John W. Eaton <jwe@octave.org> |
---|---|
date | Tue, 17 May 2016 12:09:30 -0400 |
parents | ecce63c99c3f |
children | 112b20240c87 |
line wrap: on
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/* Copyright (C) 2002-2015 John W. Eaton This file is part of Octave. Octave is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. Octave is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with Octave; see the file COPYING. If not, see <http://www.gnu.org/licenses/>. */ // Author: Paul Kienzle <pkienzle@users.sf.net> #if defined (HAVE_CONFIG_H) # include "config.h" #endif #include "dMatrix.h" #include "fMatrix.h" #include "CMatrix.h" #include "fCMatrix.h" #include "dSparse.h" #include "CSparse.h" #include "dDiagMatrix.h" #include "fDiagMatrix.h" #include "CDiagMatrix.h" #include "fCDiagMatrix.h" #include "PermMatrix.h" #include "mx-inlines.cc" #include "quit.h" #include "defun.h" #include "error.h" #include "ovl.h" template <typename R, typename T> static MArray<T> kron (const MArray<R>& a, const MArray<T>& b) { assert (a.ndims () == 2); assert (b.ndims () == 2); octave_idx_type nra = a.rows (); octave_idx_type nrb = b.rows (); octave_idx_type nca = a.cols (); octave_idx_type ncb = b.cols (); MArray<T> c (dim_vector (nra*nrb, nca*ncb)); T *cv = c.fortran_vec (); for (octave_idx_type ja = 0; ja < nca; ja++) for (octave_idx_type jb = 0; jb < ncb; jb++) for (octave_idx_type ia = 0; ia < nra; ia++) { octave_quit (); mx_inline_mul (nrb, cv, a(ia, ja), b.data () + nrb*jb); cv += nrb; } return c; } template <typename R, typename T> static MArray<T> kron (const MDiagArray2<R>& a, const MArray<T>& b) { assert (b.ndims () == 2); octave_idx_type nra = a.rows (); octave_idx_type nrb = b.rows (); octave_idx_type dla = a.diag_length (); octave_idx_type nca = a.cols (); octave_idx_type ncb = b.cols (); MArray<T> c (dim_vector (nra*nrb, nca*ncb), T ()); for (octave_idx_type ja = 0; ja < dla; ja++) for (octave_idx_type jb = 0; jb < ncb; jb++) { octave_quit (); mx_inline_mul (nrb, &c.xelem (ja*nrb, ja*ncb + jb), a.dgelem (ja), b.data () + nrb*jb); } return c; } template <typename T> static MSparse<T> kron (const MSparse<T>& A, const MSparse<T>& B) { octave_idx_type idx = 0; MSparse<T> C (A.rows () * B.rows (), A.columns () * B.columns (), A.nnz () * B.nnz ()); C.cidx (0) = 0; for (octave_idx_type Aj = 0; Aj < A.columns (); Aj++) for (octave_idx_type Bj = 0; Bj < B.columns (); Bj++) { octave_quit (); for (octave_idx_type Ai = A.cidx (Aj); Ai < A.cidx (Aj+1); Ai++) { octave_idx_type Ci = A.ridx (Ai) * B.rows (); const T v = A.data (Ai); for (octave_idx_type Bi = B.cidx (Bj); Bi < B.cidx (Bj+1); Bi++) { C.data (idx) = v * B.data (Bi); C.ridx (idx++) = Ci + B.ridx (Bi); } } C.cidx (Aj * B.columns () + Bj + 1) = idx; } return C; } static PermMatrix kron (const PermMatrix& a, const PermMatrix& b) { octave_idx_type na = a.rows (); octave_idx_type nb = b.rows (); const Array<octave_idx_type>& pa = a.col_perm_vec (); const Array<octave_idx_type>& pb = b.col_perm_vec (); Array<octave_idx_type> res_perm (dim_vector (na * nb, 1)); octave_idx_type rescol = 0; for (octave_idx_type i = 0; i < na; i++) { octave_idx_type a_add = pa(i) * nb; for (octave_idx_type j = 0; j < nb; j++) res_perm.xelem (rescol++) = a_add + pb(j); } return PermMatrix (res_perm, true); } template <typename MTA, typename MTB> octave_value do_kron (const octave_value& a, const octave_value& b) { MTA am = octave_value_extract<MTA> (a); MTB bm = octave_value_extract<MTB> (b); return octave_value (kron (am, bm)); } octave_value dispatch_kron (const octave_value& a, const octave_value& b) { octave_value retval; if (a.is_perm_matrix () && b.is_perm_matrix ()) retval = do_kron<PermMatrix, PermMatrix> (a, b); else if (a.is_sparse_type () || b.is_sparse_type ()) { if (a.is_complex_type () || b.is_complex_type ()) retval = do_kron<SparseComplexMatrix, SparseComplexMatrix> (a, b); else retval = do_kron<SparseMatrix, SparseMatrix> (a, b); } else if (a.is_diag_matrix ()) { if (b.is_diag_matrix () && a.rows () == a.columns () && b.rows () == b.columns ()) { // We have two diagonal matrices, the product of those will be // another diagonal matrix. To do that efficiently, extract // the diagonals as vectors and compute the product. That // will be another vector, which we then use to construct a // diagonal matrix object. Note that this will fail if our // digaonal matrix object is modified to allow the nonzero // values to be stored off of the principal diagonal (i.e., if // diag ([1,2], 3) is modified to return a diagonal matrix // object instead of a full matrix object). octave_value tmp = dispatch_kron (a.diag (), b.diag ()); retval = tmp.diag (); } else if (a.is_single_type () || b.is_single_type ()) { if (a.is_complex_type ()) retval = do_kron<FloatComplexDiagMatrix, FloatComplexMatrix> (a, b); else if (b.is_complex_type ()) retval = do_kron<FloatDiagMatrix, FloatComplexMatrix> (a, b); else retval = do_kron<FloatDiagMatrix, FloatMatrix> (a, b); } else { if (a.is_complex_type ()) retval = do_kron<ComplexDiagMatrix, ComplexMatrix> (a, b); else if (b.is_complex_type ()) retval = do_kron<DiagMatrix, ComplexMatrix> (a, b); else retval = do_kron<DiagMatrix, Matrix> (a, b); } } else if (a.is_single_type () || b.is_single_type ()) { if (a.is_complex_type ()) retval = do_kron<FloatComplexMatrix, FloatComplexMatrix> (a, b); else if (b.is_complex_type ()) retval = do_kron<FloatMatrix, FloatComplexMatrix> (a, b); else retval = do_kron<FloatMatrix, FloatMatrix> (a, b); } else { if (a.is_complex_type ()) retval = do_kron<ComplexMatrix, ComplexMatrix> (a, b); else if (b.is_complex_type ()) retval = do_kron<Matrix, ComplexMatrix> (a, b); else retval = do_kron<Matrix, Matrix> (a, b); } return retval; } DEFUN (kron, args, , "-*- texinfo -*-\n\ @deftypefn {} {} kron (@var{A}, @var{B})\n\ @deftypefnx {} {} kron (@var{A1}, @var{A2}, @dots{})\n\ Form the Kronecker product of two or more matrices.\n\ \n\ This is defined block by block as\n\ \n\ @example\n\ x = [ a(i,j)*b ]\n\ @end example\n\ \n\ For example:\n\ \n\ @example\n\ @group\n\ kron (1:4, ones (3, 1))\n\ @result{} 1 2 3 4\n\ 1 2 3 4\n\ 1 2 3 4\n\ @end group\n\ @end example\n\ \n\ If there are more than two input arguments @var{A1}, @var{A2}, @dots{},\n\ @var{An} the Kronecker product is computed as\n\ \n\ @example\n\ kron (kron (@var{A1}, @var{A2}), @dots{}, @var{An})\n\ @end example\n\ \n\ @noindent\n\ Since the Kronecker product is associative, this is well-defined.\n\ @end deftypefn") { int nargin = args.length (); if (nargin < 2) print_usage (); octave_value retval; octave_value a = args(0); octave_value b = args(1); retval = dispatch_kron (a, b); for (octave_idx_type i = 2; i < nargin; i++) retval = dispatch_kron (retval, args(i)); return retval; } /* %!test %! x = ones (2); %! assert (kron (x, x), ones (4)); %!shared x, y, z, p1, p2, d1, d2 %! x = [1, 2]; %! y = [-1, -2]; %! z = [1, 2, 3, 4; 1, 2, 3, 4; 1, 2, 3, 4]; %! p1 = eye (3)([2, 3, 1], :); ## Permutation matrix %! p2 = [0 1 0; 0 0 1; 1 0 0]; ## Non-permutation equivalent %! d1 = diag ([1 2 3]); ## Diag type matrix %! d2 = [1 0 0; 0 2 0; 0 0 3]; ## Non-diag equivalent %!assert (kron (1:4, ones (3, 1)), z) %!assert (kron (single (1:4), ones (3, 1)), single (z)) %!assert (kron (sparse (1:4), ones (3, 1)), sparse (z)) %!assert (kron (complex (1:4), ones (3, 1)), z) %!assert (kron (complex (single(1:4)), ones (3, 1)), single(z)) %!assert (kron (x, y, z), kron (kron (x, y), z)) %!assert (kron (x, y, z), kron (x, kron (y, z))) %!assert (kron (p1, p1), kron (p2, p2)) %!assert (kron (p1, p2), kron (p2, p1)) %!assert (kron (d1, d1), kron (d2, d2)) %!assert (kron (d1, d2), kron (d2, d1)) %!assert (kron (diag ([1, 2]), diag ([3, 4])), diag ([3, 4, 6, 8])) %% Test for two diag matrices. See the comments above in %% dispatch_kron for this case. %% %!test %! expected = zeros (16, 16); %! expected (1, 11) = 3; %! expected (2, 12) = 4; %! expected (5, 15) = 6; %! expected (6, 16) = 8; %! assert (kron (diag ([1, 2], 2), diag ([3, 4], 2)), expected); */