Press n or j to go to the next uncovered block, b, p or k for the previous block.
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* @license Apache-2.0
*
* Copyright (c) 2026 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
'use strict';
/* eslint-disable max-len, max-statements, max-lines-per-function */
// MODULES //
var Float64Array = require( '@stdlib/array/float64' );
var dlamch = require( '@stdlib/lapack/base/dlamch' );
var pow = require( '@stdlib/math/base/special/pow' );
var max = require( '@stdlib/math/base/special/max' );
var min = require( '@stdlib/math/base/special/min' );
var sqrt = require( '@stdlib/math/base/special/sqrt' );
var abs = require( '@stdlib/math/base/special/abs' );
var floor = require( '@stdlib/math/base/special/floor' );
var dlasq3 = require( './dlasq3.js' );
var dlasrt = require( './dlasrt.js' );
// VARIABLES //
var CBIAS = 1.50;
var EPS = dlamch( 'P' );
var TOL = EPS * 100;
var TOL2 = pow( TOL, 2 );
var SAFMIN = dlamch( 'S' );
var IEEE = true;
// MAIN //
/**
* Computes all the eigenvalues of the symmetric positive definite tri-diagonal matrix associated with the QD Array `Z` to high relative accuracy.
*
* @private
* @param {integer} N - number of rows/columns in `Z`
* @param {Float64Array} Z - qd array
* @param {integer} strideZ - stride length for `Z`
* @param {NonNegativeInteger} offsetZ - starting index of `Z`
* @returns {integer} status code
*
* @example
* var Float64Array = require( '@stdlib/array/float64' );
*
* var Z = new Float64Array( [ 100, 4, 81, 3, 64, 2.5, 49, 2, 36, 1.5, 25, 1, 16, 0.5, 9, 0 ] );
*
* var out = dlasq2( 4, Z, 1, 0 );
* // Z => <Float64Array>[ ~115.713, ~83.153, ~62.17, ~42.464, ~83.153, ~20.987, ~0.0, ~0.0, 303.5, ~303.5, 15, 4.0625, 0.0, ~0.0, ~0.172, ~0.096 ]
* // out => 0
*/
function dlasq2( N, Z, strideZ, offsetZ ) { // eslint-disable-line stdlib/jsdoc-doctest-decimal-point
var deemin;
var oldemn;
var iwhila;
var iwhilb;
var desig;
var dmin1;
var dmin2;
var sigma;
var trace;
var tempq;
var tempe;
var ttype;
var nfail;
var emax;
var emin;
var iter;
var nbig;
var ndiv;
var ipn4;
var kmin;
var dmin;
var qmax;
var qmin;
var temp;
var zmax;
var splt;
var dee;
var tau;
var dn1;
var dn2;
var out;
var pp;
var i0;
var i1;
var i4;
var n0;
var n1;
var dn;
var d;
var e;
var g;
var k;
var s;
var t;
out = new Float64Array( 18 );
if ( N === 0 ) {
return 0;
}
if ( N === 1 ) {
// 1-by-1 case
if ( Z[ offsetZ ] < 0 ) {
return -201;
}
return 0;
}
if ( N === 2 ) {
// 2-by-2 case
if ( Z[ offsetZ ] < 0 ) {
return -201;
}
if ( Z[ offsetZ + strideZ ] < 0 ) {
return -202;
}
if ( Z[ offsetZ + ( 2 * strideZ ) ] < 0 ) {
return -203;
}
if ( Z[ offsetZ + ( 2 * strideZ ) ] > Z[ offsetZ ] ) {
d = Z[ offsetZ + ( 2 * strideZ ) ];
Z[ offsetZ + ( 2 * strideZ ) ] = Z[ offsetZ ];
Z[ offsetZ ] = d;
}
Z[ offsetZ + ( 4 * strideZ ) ] = Z[ offsetZ ] + Z[ offsetZ + strideZ ] + Z[ offsetZ + ( 2 * strideZ ) ];
if ( Z[ offsetZ + strideZ ] > Z[ offsetZ + ( 2 * strideZ ) ] * TOL2 ) {
t = 0.5 * ( ( Z[ offsetZ ] - Z[ offsetZ + ( 2 * strideZ ) ] ) + Z[ offsetZ + strideZ ] );
s = Z[ offsetZ + ( 2 * strideZ ) ] * ( Z[ offsetZ + strideZ ] / t );
if ( s <= t ) {
s = Z[ offsetZ + ( 2 * strideZ ) ] * ( Z[ offsetZ + strideZ ] / ( t * ( 1 + sqrt( 1 + ( s / t ) ) ) ) );
} else {
s = Z[ offsetZ + ( 2 * strideZ ) ] * ( Z[ offsetZ + strideZ ] / ( t + ( sqrt( t ) * sqrt( t + s ) ) ) );
}
t = Z[ offsetZ ] + ( s + Z[ offsetZ + strideZ ] );
Z[ offsetZ + ( 2 * strideZ ) ] = Z[ offsetZ + ( 2 * strideZ ) ] * ( Z[ offsetZ ] / t );
Z[ offsetZ ] = t;
}
Z[ offsetZ + strideZ ] = Z[ offsetZ + ( 2 * strideZ ) ];
Z[ offsetZ + ( 5 * strideZ ) ] = Z[ offsetZ + strideZ ] + Z[ offsetZ ];
return 0;
}
// Check for negative data and compute sums of q's and e's
Z[ offsetZ + ( ( ( 2 * N ) - 1 ) * strideZ ) ] = 0;
emin = Z[ offsetZ + strideZ ];
qmax = 0;
zmax = 0;
d = 0;
e = 0;
for ( k = 0; k < 2 * ( N - 1 ); k += 2 ) {
if ( Z[ offsetZ + ( k * strideZ ) ] < 0 ) {
return -( 200 + k );
}
if ( Z[ offsetZ + ( k * strideZ ) + strideZ ] < 0 ) {
return -( 200 + k + 1 );
}
d += Z[ offsetZ + ( k * strideZ ) ];
e += Z[ offsetZ + ( k * strideZ ) + strideZ ];
qmax = max( qmax, Z[ offsetZ + ( k * strideZ ) ] );
emin = min( emin, Z[ offsetZ + ( k * strideZ ) + strideZ ] );
zmax = max( qmax, max( zmax, Z[ offsetZ + ( k * strideZ ) + strideZ ] ) );
}
if ( Z[ offsetZ + ( ( ( 2 * N ) - 2 ) * strideZ ) ] < 0 ) {
return -( 200 + ( 2 * N ) - 1 );
}
d += Z[ offsetZ + ( ( ( 2 * N ) - 2 ) * strideZ ) ];
qmax = max( qmax, Z[ offsetZ + ( ( ( 2 * N ) - 2 ) * strideZ ) ] );
zmax = max( qmax, zmax );
// Check for diagonality
if ( e === 0 ) {
for ( k = 1; k < N; k++ ) {
Z[ offsetZ + ( k * strideZ ) ] = Z[ offsetZ + ( ( ( 2 * k ) + 1 ) * strideZ ) ];
}
dlasrt( 'decreasing', N, Z, strideZ, offsetZ );
Z[ offsetZ + ( ( ( 2 * N ) - 2 ) * strideZ ) ] = d;
return 0;
}
trace = d + e;
// Check for zero data
if ( trace === 0 ) {
Z[ offsetZ + ( ( ( 2 * N ) - 2 ) * strideZ ) ] = 0;
return 0;
}
// Check whether the machine is IEEE conformable (In JS, always true)
IEEE = true;
// Rearrange data for locality: Z=(q1,qq1,e1,ee1,q2,qq2,e2,ee2,...)
for ( k = ( 2 * N ) - 1; k >= 1; k -= 2 ) {
Z[ offsetZ + ( ( ( 2 * k ) + 1 ) * strideZ ) ] = 0;
Z[ offsetZ + ( ( 2 * k ) * strideZ ) ] = Z[ offsetZ + ( k * strideZ ) ];
Z[ offsetZ + ( ( ( 2 * k ) - 1 ) * strideZ ) ] = 0;
Z[ offsetZ + ( ( ( 2 * k ) - 2 ) * strideZ ) ] = Z[ offsetZ + ( k * strideZ ) - strideZ ];
}
i0 = 0;
n0 = N-1;
// Reverse the qd-array, if warranted
if ( CBIAS * Z[ offsetZ + ( ( 4 * i0 ) * strideZ ) ] < Z[ offsetZ + ( ( 4 * n0 ) * strideZ ) ] ) {
ipn4 = ( 4 * ( i0 + n0 ) ) + 6;
for ( i4 = ( 4 * i0 ) + 3; i4 <= ( 2 * ( i0 + n0 ) ) + 1; i4 += 4 ) {
temp = Z[ offsetZ + ( ( i4 - 3 ) * strideZ ) ];
Z[ offsetZ + ( ( i4 - 3 ) * strideZ ) ] = Z[ offsetZ + ( ( ipn4 - i4 - 3 ) * strideZ ) ];
Z[ offsetZ + ( ( ipn4 - i4 - 3 ) * strideZ ) ] = temp;
temp = Z[ offsetZ + ( ( i4 - 1 ) * strideZ ) ];
Z[ offsetZ + ( ( i4 - 1 ) * strideZ ) ] = Z[ offsetZ + ( ( ipn4 - i4 - 5 ) * strideZ ) ];
Z[ offsetZ + ( ( ipn4 - i4 - 5 ) * strideZ ) ] = temp;
}
}
// Initial split checking via DQD and Li's test
pp = 0;
for ( k = 0; k < 2; k++ ) {
d = Z[ offsetZ + ( ( ( 4 * n0 ) + pp ) * strideZ ) ];
for ( i4 = ( 4 * n0 ) - 1 + pp; i4 >= ( 4 * i0 ) + pp + 3; i4 -= 4 ) {
if ( Z[ offsetZ + ( ( i4 - 1 ) * strideZ ) ] <= TOL2 * d ) {
Z[ offsetZ + ( ( i4 - 1 ) * strideZ ) ] = -0;
d = Z[ offsetZ + ( ( i4 - 3 ) * strideZ ) ];
} else {
d = Z[ offsetZ + ( ( i4 - 3 ) * strideZ ) ] * ( d / ( d + Z[ offsetZ + ( ( i4 - 1 ) * strideZ ) ] ) );
}
}
// DQD maps Z to ZZ plus Li's test
emin = Z[ offsetZ + ( ( ( 4 * i0 ) + pp + 4 ) * strideZ ) ];
d = Z[ offsetZ + ( ( ( 4 * i0 ) + pp ) * strideZ ) ];
for ( i4 = ( 4 * i0 ) + pp + 3; i4 <= ( 4 * n0 ) + pp - 1; i4 += 4 ) {
Z[ offsetZ + ( ( i4 - ( 2 * pp ) - 2 ) * strideZ ) ] = d + Z[ offsetZ + ( ( i4 - 1 ) * strideZ ) ];
if ( Z[ offsetZ + ( ( i4 - 1 ) * strideZ ) ] <= TOL2 * d ) {
Z[ offsetZ + ( ( i4 - 1 ) * strideZ ) ] = -0;
Z[ offsetZ + ( ( i4 - ( 2 * pp ) - 2 ) * strideZ ) ] = d;
Z[ offsetZ + ( ( i4 - ( 2 * pp ) ) * strideZ ) ] = 0;
d = Z[ offsetZ + ( ( i4 + 1 ) * strideZ ) ];
} else if ( ( SAFMIN * Z[ offsetZ + ( ( i4 + 1 ) * strideZ ) ] < Z[ offsetZ + ( ( i4 - ( 2 * pp ) - 2 ) * strideZ ) ] ) && ( SAFMIN * Z[ offsetZ + ( ( i4 - ( 2 * pp ) - 2 ) * strideZ ) ] < Z[ offsetZ + ( ( i4 + 1 ) * strideZ ) ] ) ) {
temp = Z[ offsetZ + ( ( i4 + 1 ) * strideZ ) ] / Z[ offsetZ + ( ( i4 - ( 2 * pp ) - 2 ) * strideZ ) ];
Z[ offsetZ + ( ( i4 - ( 2 * pp ) ) * strideZ ) ] = Z[ offsetZ + ( ( i4 - 1 ) * strideZ ) ] * temp;
d *= temp;
} else {
Z[ offsetZ + ( ( i4 - ( 2 * pp ) ) * strideZ ) ] = Z[ offsetZ + ( ( i4 + 1 ) * strideZ ) ] * ( Z[ offsetZ + ( ( i4 - 1 ) * strideZ ) ] / Z[ offsetZ + ( ( i4 - ( 2 * pp ) - 2 ) * strideZ ) ] );
d = Z[ offsetZ + ( ( i4 + 1 ) * strideZ ) ] * ( d / Z[ offsetZ + ( ( i4 - ( 2 * pp ) - 2 ) * strideZ ) ] );
}
emin = min( emin, Z[ offsetZ + ( ( i4 - ( 2 * pp ) ) * strideZ ) ] );
}
Z[ offsetZ + ( ( ( 4 * n0 ) - pp + 1 ) * strideZ ) ] = d;
// Now find qmax
qmax = Z[ offsetZ + ( ( ( 4 * i0 ) - pp + 1 ) * strideZ ) ];
for ( i4 = ( 4 * i0 ) - pp + 5; i4 <= ( 4 * n0 ) - pp + 1; i4 += 4 ) {
qmax = max( qmax, Z[ offsetZ + ( i4 * strideZ ) ] );
}
// Prepare for the next iteration on K
pp = 1 - pp;
}
// Initialize variables to pass to DLASQ3
ttype = 0;
dmin1 = 0;
dmin2 = 0;
dn = 0;
dn1 = 0;
dn2 = 0;
g = 0;
tau = 0;
iter = 2;
nfail = 0;
ndiv = 2 * ( n0 - i0 );
for ( iwhila = 0; iwhila <= N; iwhila++ ) {
if ( n0 < 0 ) {
// Move q's to the front
for ( k = 1; k < N; k++ ) {
Z[ offsetZ + ( k * strideZ ) ] = Z[ offsetZ + ( ( 4 * k ) * strideZ ) ];
}
// Sort and compute sum of eigenvalues
dlasrt( 'decreasing', N, Z, strideZ, offsetZ );
e = 0;
for ( k = N - 1; k >= 0; k-- ) {
e += Z[ offsetZ + ( k * strideZ ) ];
}
// Store trace, sum(eigenvalues) and information on performance
Z[ offsetZ + ( ( 2 * N ) * strideZ ) ] = trace;
Z[ offsetZ + ( ( ( 2 * N ) + 1 ) * strideZ ) ] = e;
Z[ offsetZ + ( ( ( 2 * N ) + 2 ) * strideZ ) ] = iter;
Z[ offsetZ + ( ( ( 2 * N ) + 3 ) * strideZ ) ] = ndiv / ( N * N );
Z[ offsetZ + ( ( ( 2 * N ) + 4 ) * strideZ ) ] = ( 100 * nfail ) / iter;
return 0;
}
// E(N0) holds the value of SIGMA when submatrix in I0:N0 splits from the rest of the array, but is negated.
desig = 0;
if ( n0 === N - 1 ) {
sigma = 0;
} else {
sigma = -Z[ offsetZ + ( ( ( 4 * n0 ) + 2 ) * strideZ ) ];
}
if ( sigma < 0 ) {
return 1;
}
// Find last unreduced submatrix's top index I0, find QMAX and EMIN. Find Gershgorin-type bound if Q's much greater than E's.
emax = 0;
if ( n0 > i0 ) {
emin = abs( Z[ offsetZ + ( ( ( 4 * n0 ) - 2 ) * strideZ ) ] );
} else {
emin = 0;
}
qmin = Z[ offsetZ + ( ( 4 * n0 ) * strideZ ) ];
qmax = qmin;
for ( i4 = ( 4 * n0 ) + 3; i4 >= 7; i4 -= 4 ) {
if ( Z[ offsetZ + ( ( i4 - 5 ) * strideZ ) ] <= 0 ) {
break;
}
if ( qmin >= 4 * emax ) {
qmin = min( qmin, Z[ offsetZ + ( ( i4 - 3 ) * strideZ ) ] );
emax = max( emax, Z[ offsetZ + ( ( i4 - 5 ) * strideZ ) ] );
}
qmax = max( qmax, Z[ offsetZ + ( ( i4 - 7 ) * strideZ ) ] + Z[ offsetZ + ( ( i4 - 5 ) * strideZ ) ] );
emin = min( emin, Z[ offsetZ + ( ( i4 - 5 ) * strideZ ) ] );
}
// If the loop completed without break, set i4 = 4
if ( i4 < 7 ) {
i4 = 3;
}
i0 = floor( ( ( i4 + 1 ) / 4 ) - 1 );
pp = 0;
if ( n0 - i0 > 1 ) {
dee = Z[ offsetZ + ( ( 4 * i0 ) * strideZ ) ];
deemin = dee;
kmin = i0;
for ( i4 = ( 4 * i0 ) + 4; i4 <= 4 * n0; i4 += 4 ) {
dee = Z[ offsetZ + ( i4 * strideZ ) ] * ( dee / ( dee + Z[ offsetZ + ( ( i4 - 2 ) * strideZ ) ] ) );
if ( dee <= deemin ) {
deemin = dee;
kmin = floor( i4 / 4 );
}
}
if ( ( ( kmin - i0 ) * 2 < n0 - kmin ) && ( deemin <= 0.5 * Z[ offsetZ + ( ( 4 * n0 ) * strideZ ) ] ) ) {
ipn4 = ( 4 * ( i0 + n0 ) ) + 7;
pp = 2;
for ( i4 = ( 4 * i0 ) + 3; i4 <= ( 2 * ( i0 + n0 ) ) + 1; i4 += 4 ) {
temp = Z[ offsetZ + ( ( i4 - 3 ) * strideZ ) ];
Z[ offsetZ + ( ( i4 - 3 ) * strideZ ) ] = Z[ offsetZ + ( ( ipn4 - i4 - 3 ) * strideZ ) ];
Z[ offsetZ + ( ( ipn4 - i4 - 3 ) * strideZ ) ] = temp;
temp = Z[ offsetZ + ( ( i4 - 2 ) * strideZ ) ];
Z[ offsetZ + ( ( i4 - 2 ) * strideZ ) ] = Z[ offsetZ + ( ( ipn4 - i4 - 2 ) * strideZ ) ];
Z[ offsetZ + ( ( ipn4 - i4 - 2 ) * strideZ ) ] = temp;
temp = Z[ offsetZ + ( ( i4 - 1 ) * strideZ ) ];
Z[ offsetZ + ( ( i4 - 1 ) * strideZ ) ] = Z[ offsetZ + ( ( ipn4 - i4 - 5 ) * strideZ ) ];
Z[ offsetZ + ( ( ipn4 - i4 - 5 ) * strideZ ) ] = temp;
temp = Z[ offsetZ + ( i4 * strideZ ) ];
Z[ offsetZ + ( i4 * strideZ ) ] = Z[ offsetZ + ( ( ipn4 - i4 - 4 ) * strideZ ) ];
Z[ offsetZ + ( ( ipn4 - i4 - 4 ) * strideZ ) ] = temp;
}
}
}
// Put -(initial shift) into DMIN
dmin = -max( 0, qmin - ( 2 * sqrt( qmin ) * sqrt( emax ) ) );
/*
Now I0:N0 is unreduced.
PP = 0 for ping,
PP = 1 for pong,
PP = 2 indicates that flipping was applied to the Z array and that the tests for deflation upon entry in DLASQ3 should not be performed.
*/
nbig = 100 * ( n0 - i0 + 1 );
for ( iwhilb = 0; iwhilb < nbig; iwhilb++ ) {
if ( i0 > n0 ) {
break;
}
out[ 0 ] = n0;
out[ 1 ] = pp;
out[ 2 ] = dmin;
out[ 3 ] = sigma;
out[ 4 ] = desig;
out[ 5 ] = qmax;
out[ 6 ] = nfail;
out[ 7 ] = iter;
out[ 8 ] = ndiv;
out[ 9 ] = ttype;
out[ 10 ] = dmin1;
out[ 11 ] = dmin2;
out[ 12 ] = dn;
out[ 13 ] = dn1;
out[ 14 ] = dn2;
out[ 15 ] = g;
out[ 16 ] = tau;
// Call dlasq3
dlasq3( i0, Z, strideZ, offsetZ, IEEE, out, 1, 0 );
n0 = out[ 0 ];
pp = out[ 1 ];
dmin = out[ 2 ];
sigma = out[ 3 ];
desig = out[ 4 ];
qmax = out[ 5 ];
nfail = out[ 6 ];
iter = out[ 7 ];
ndiv = out[ 8 ];
ttype = out[ 9 ];
dmin1 = out[ 10 ];
dmin2 = out[ 11 ];
dn = out[ 12 ];
dn1 = out[ 13 ];
dn2 = out[ 14 ];
g = out[ 15 ];
tau = out[ 16 ];
pp = 1 - pp;
// When EMIN is very small check for splits
if ( pp === 0 && n0 - i0 >= 3 ) {
if ( ( Z[ offsetZ + ( ( ( 4 * n0 ) + 3 ) * strideZ ) ] <= TOL2 * qmax ) || ( Z[ offsetZ + ( ( ( 4 * n0 ) + 2 ) * strideZ ) ] <= TOL2 * sigma ) ) {
splt = i0 - 1;
qmax = Z[ offsetZ + ( ( 4 * i0 ) * strideZ ) ];
emin = Z[ offsetZ + ( ( ( 4 * i0 ) + 2 ) * strideZ ) ];
oldemn = Z[ offsetZ + ( ( ( 4 * i0 ) + 3 ) * strideZ ) ];
for ( i4 = ( 4 * i0 ) + 3; i4 <= ( 4 * n0 ) - 9; i4 += 4 ) {
if ( ( Z[ offsetZ + ( i4 * strideZ ) ] <= TOL2 * Z[ offsetZ + ( ( i4 - 3 ) * strideZ ) ] ) || ( Z[ offsetZ + ( ( i4 - 1 ) * strideZ ) ] <= TOL2 * sigma) ) {
Z[ offsetZ + ( ( i4 - 1 ) * strideZ ) ] = -sigma;
splt = floor( ( i4 + 1 ) / 4 ) - 1;
qmax = 0;
emin = Z[ offsetZ + ( ( i4 + 3 ) * strideZ ) ];
oldemn = Z[ offsetZ + ( ( i4 + 4 ) * strideZ ) ];
} else {
qmax = max( qmax, Z[ offsetZ + ( ( i4 + 1 ) * strideZ ) ] );
emin = min( emin, Z[ offsetZ + ( ( i4 - 1 ) * strideZ ) ] );
oldemn = min( oldemn, Z[ offsetZ + ( i4 * strideZ ) ] );
}
}
Z[ offsetZ + ( ( ( 4 * n0 ) + 2 ) * strideZ ) ] = emin;
Z[ offsetZ + ( ( ( 4 * n0 ) + 3 ) * strideZ ) ] = oldemn;
i0 = splt + 1;
}
}
}
// If inner loop exhausted without breaking, we have INFO = 2
if ( iwhilb >= nbig ) {
// Maximum number of iterations exceeded, restore the shift SIGMA and place the new d's and e's in a qd array. This might need to be done for several blocks
i1 = i0;
n1 = n0;
// Label 145 loop
while ( true ) {
tempq = Z[ offsetZ + ( ( 4 * i0 ) * strideZ ) ];
Z[ offsetZ + ( ( 4 * i0 ) * strideZ ) ] += sigma;
for ( k = i0 + 1; k <= n0; k++ ) {
tempe = Z[ offsetZ + ( ( ( 4 * k ) - 2 ) * strideZ ) ];
Z[ offsetZ + ( ( ( 4 * k ) - 2 ) * strideZ ) ] *= tempq / Z[ offsetZ + ( ( ( 4 * k ) - 4 ) * strideZ ) ];
tempq = Z[ offsetZ + ( ( 4 * k ) * strideZ ) ];
Z[ offsetZ + ( ( 4 * k ) * strideZ ) ] += sigma + tempe - Z[ offsetZ + ( ( ( 4 * k ) - 2 ) * strideZ ) ];
}
// Prepare to do this on the previous block if there is one
if ( i1 > 0 ) {
n1 = i1 - 1;
while ( i1 >= 1 && Z[ offsetZ + ( ( ( 4 * i1 ) - 2 ) * strideZ ) ] >= 0 ) {
i1 -= 1;
}
sigma = -Z[ offsetZ + ( ( ( 4 * n1 ) + 2 ) * strideZ ) ];
} else {
break;
}
}
for ( k = 0; k < N; k++ ) {
Z[ offsetZ + ( ( 2 * k ) * strideZ ) ] = Z[ offsetZ + ( ( 4 * k ) * strideZ ) ];
if ( k < n0 ) {
Z[ offsetZ + ( ( ( 2 * k ) + 1 ) * strideZ ) ] = Z[ offsetZ + ( ( ( 4 * k ) + 2 ) * strideZ ) ];
} else {
Z[ offsetZ + ( ( ( 2 * k ) + 1 ) * strideZ ) ] = 0;
}
}
return 2;
}
}
return 3;
}
// EXPORTS //
module.exports = dlasq2;
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