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author | shmel1k <shmel1k@ydb.tech> | 2022-09-02 12:44:59 +0300 |
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committer | shmel1k <shmel1k@ydb.tech> | 2022-09-02 12:44:59 +0300 |
commit | 90d450f74722da7859d6f510a869f6c6908fd12f (patch) | |
tree | 538c718dedc76cdfe37ad6d01ff250dd930d9278 /contrib/libs/clapack/csptrf.c | |
parent | 01f64c1ecd0d4ffa9e3a74478335f1745f26cc75 (diff) | |
download | ydb-90d450f74722da7859d6f510a869f6c6908fd12f.tar.gz |
[] add metering mode to CLI
Diffstat (limited to 'contrib/libs/clapack/csptrf.c')
-rw-r--r-- | contrib/libs/clapack/csptrf.c | 763 |
1 files changed, 763 insertions, 0 deletions
diff --git a/contrib/libs/clapack/csptrf.c b/contrib/libs/clapack/csptrf.c new file mode 100644 index 0000000000..753039b077 --- /dev/null +++ b/contrib/libs/clapack/csptrf.c @@ -0,0 +1,763 @@ +/* csptrf.f -- translated by f2c (version 20061008). + You must link the resulting object file with libf2c: + on Microsoft Windows system, link with libf2c.lib; + on Linux or Unix systems, link with .../path/to/libf2c.a -lm + or, if you install libf2c.a in a standard place, with -lf2c -lm + -- in that order, at the end of the command line, as in + cc *.o -lf2c -lm + Source for libf2c is in /netlib/f2c/libf2c.zip, e.g., + + http://www.netlib.org/f2c/libf2c.zip +*/ + +#include "f2c.h" +#include "blaswrap.h" + +/* Table of constant values */ + +static complex c_b1 = {1.f,0.f}; +static integer c__1 = 1; + +/* Subroutine */ int csptrf_(char *uplo, integer *n, complex *ap, integer * + ipiv, integer *info) +{ + /* System generated locals */ + integer i__1, i__2, i__3, i__4, i__5, i__6; + real r__1, r__2, r__3, r__4; + complex q__1, q__2, q__3, q__4; + + /* Builtin functions */ + double sqrt(doublereal), r_imag(complex *); + void c_div(complex *, complex *, complex *); + + /* Local variables */ + integer i__, j, k; + complex t, r1, d11, d12, d21, d22; + integer kc, kk, kp; + complex wk; + integer kx, knc, kpc, npp; + complex wkm1, wkp1; + integer imax, jmax; + extern /* Subroutine */ int cspr_(char *, integer *, complex *, complex *, + integer *, complex *); + real alpha; + extern /* Subroutine */ int cscal_(integer *, complex *, complex *, + integer *); + extern logical lsame_(char *, char *); + extern /* Subroutine */ int cswap_(integer *, complex *, integer *, + complex *, integer *); + integer kstep; + logical upper; + real absakk; + extern integer icamax_(integer *, complex *, integer *); + extern /* Subroutine */ int xerbla_(char *, integer *); + real colmax, rowmax; + + +/* -- LAPACK routine (version 3.2) -- */ +/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */ +/* November 2006 */ + +/* .. Scalar Arguments .. */ +/* .. */ +/* .. Array Arguments .. */ +/* .. */ + +/* Purpose */ +/* ======= */ + +/* CSPTRF computes the factorization of a complex symmetric matrix A */ +/* stored in packed format using the Bunch-Kaufman diagonal pivoting */ +/* method: */ + +/* A = U*D*U**T or A = L*D*L**T */ + +/* where U (or L) is a product of permutation and unit upper (lower) */ +/* triangular matrices, and D is symmetric and block diagonal with */ +/* 1-by-1 and 2-by-2 diagonal blocks. */ + +/* Arguments */ +/* ========= */ + +/* UPLO (input) CHARACTER*1 */ +/* = 'U': Upper triangle of A is stored; */ +/* = 'L': Lower triangle of A is stored. */ + +/* N (input) INTEGER */ +/* The order of the matrix A. N >= 0. */ + +/* AP (input/output) COMPLEX array, dimension (N*(N+1)/2) */ +/* On entry, the upper or lower triangle of the symmetric matrix */ +/* A, packed columnwise in a linear array. The j-th column of A */ +/* is stored in the array AP as follows: */ +/* if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j; */ +/* if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = A(i,j) for j<=i<=n. */ + +/* On exit, the block diagonal matrix D and the multipliers used */ +/* to obtain the factor U or L, stored as a packed triangular */ +/* matrix overwriting A (see below for further details). */ + +/* IPIV (output) INTEGER array, dimension (N) */ +/* Details of the interchanges and the block structure of D. */ +/* If IPIV(k) > 0, then rows and columns k and IPIV(k) were */ +/* interchanged and D(k,k) is a 1-by-1 diagonal block. */ +/* If UPLO = 'U' and IPIV(k) = IPIV(k-1) < 0, then rows and */ +/* columns k-1 and -IPIV(k) were interchanged and D(k-1:k,k-1:k) */ +/* is a 2-by-2 diagonal block. If UPLO = 'L' and IPIV(k) = */ +/* IPIV(k+1) < 0, then rows and columns k+1 and -IPIV(k) were */ +/* interchanged and D(k:k+1,k:k+1) is a 2-by-2 diagonal block. */ + +/* INFO (output) INTEGER */ +/* = 0: successful exit */ +/* < 0: if INFO = -i, the i-th argument had an illegal value */ +/* > 0: if INFO = i, D(i,i) is exactly zero. The factorization */ +/* has been completed, but the block diagonal matrix D is */ +/* exactly singular, and division by zero will occur if it */ +/* is used to solve a system of equations. */ + +/* Further Details */ +/* =============== */ + +/* 5-96 - Based on modifications by J. Lewis, Boeing Computer Services */ +/* Company */ + +/* If UPLO = 'U', then A = U*D*U', where */ +/* U = P(n)*U(n)* ... *P(k)U(k)* ..., */ +/* i.e., U is a product of terms P(k)*U(k), where k decreases from n to */ +/* 1 in steps of 1 or 2, and D is a block diagonal matrix with 1-by-1 */ +/* and 2-by-2 diagonal blocks D(k). P(k) is a permutation matrix as */ +/* defined by IPIV(k), and U(k) is a unit upper triangular matrix, such */ +/* that if the diagonal block D(k) is of order s (s = 1 or 2), then */ + +/* ( I v 0 ) k-s */ +/* U(k) = ( 0 I 0 ) s */ +/* ( 0 0 I ) n-k */ +/* k-s s n-k */ + +/* If s = 1, D(k) overwrites A(k,k), and v overwrites A(1:k-1,k). */ +/* If s = 2, the upper triangle of D(k) overwrites A(k-1,k-1), A(k-1,k), */ +/* and A(k,k), and v overwrites A(1:k-2,k-1:k). */ + +/* If UPLO = 'L', then A = L*D*L', where */ +/* L = P(1)*L(1)* ... *P(k)*L(k)* ..., */ +/* i.e., L is a product of terms P(k)*L(k), where k increases from 1 to */ +/* n in steps of 1 or 2, and D is a block diagonal matrix with 1-by-1 */ +/* and 2-by-2 diagonal blocks D(k). P(k) is a permutation matrix as */ +/* defined by IPIV(k), and L(k) is a unit lower triangular matrix, such */ +/* that if the diagonal block D(k) is of order s (s = 1 or 2), then */ + +/* ( I 0 0 ) k-1 */ +/* L(k) = ( 0 I 0 ) s */ +/* ( 0 v I ) n-k-s+1 */ +/* k-1 s n-k-s+1 */ + +/* If s = 1, D(k) overwrites A(k,k), and v overwrites A(k+1:n,k). */ +/* If s = 2, the lower triangle of D(k) overwrites A(k,k), A(k+1,k), */ +/* and A(k+1,k+1), and v overwrites A(k+2:n,k:k+1). */ + +/* ===================================================================== */ + +/* .. Parameters .. */ +/* .. */ +/* .. Local Scalars .. */ +/* .. */ +/* .. External Functions .. */ +/* .. */ +/* .. External Subroutines .. */ +/* .. */ +/* .. Intrinsic Functions .. */ +/* .. */ +/* .. Statement Functions .. */ +/* .. */ +/* .. Statement Function definitions .. */ +/* .. */ +/* .. Executable Statements .. */ + +/* Test the input parameters. */ + + /* Parameter adjustments */ + --ipiv; + --ap; + + /* Function Body */ + *info = 0; + upper = lsame_(uplo, "U"); + if (! upper && ! lsame_(uplo, "L")) { + *info = -1; + } else if (*n < 0) { + *info = -2; + } + if (*info != 0) { + i__1 = -(*info); + xerbla_("CSPTRF", &i__1); + return 0; + } + +/* Initialize ALPHA for use in choosing pivot block size. */ + + alpha = (sqrt(17.f) + 1.f) / 8.f; + + if (upper) { + +/* Factorize A as U*D*U' using the upper triangle of A */ + +/* K is the main loop index, decreasing from N to 1 in steps of */ +/* 1 or 2 */ + + k = *n; + kc = (*n - 1) * *n / 2 + 1; +L10: + knc = kc; + +/* If K < 1, exit from loop */ + + if (k < 1) { + goto L110; + } + kstep = 1; + +/* Determine rows and columns to be interchanged and whether */ +/* a 1-by-1 or 2-by-2 pivot block will be used */ + + i__1 = kc + k - 1; + absakk = (r__1 = ap[i__1].r, dabs(r__1)) + (r__2 = r_imag(&ap[kc + k + - 1]), dabs(r__2)); + +/* IMAX is the row-index of the largest off-diagonal element in */ +/* column K, and COLMAX is its absolute value */ + + if (k > 1) { + i__1 = k - 1; + imax = icamax_(&i__1, &ap[kc], &c__1); + i__1 = kc + imax - 1; + colmax = (r__1 = ap[i__1].r, dabs(r__1)) + (r__2 = r_imag(&ap[kc + + imax - 1]), dabs(r__2)); + } else { + colmax = 0.f; + } + + if (dmax(absakk,colmax) == 0.f) { + +/* Column K is zero: set INFO and continue */ + + if (*info == 0) { + *info = k; + } + kp = k; + } else { + if (absakk >= alpha * colmax) { + +/* no interchange, use 1-by-1 pivot block */ + + kp = k; + } else { + +/* JMAX is the column-index of the largest off-diagonal */ +/* element in row IMAX, and ROWMAX is its absolute value */ + + rowmax = 0.f; + jmax = imax; + kx = imax * (imax + 1) / 2 + imax; + i__1 = k; + for (j = imax + 1; j <= i__1; ++j) { + i__2 = kx; + if ((r__1 = ap[i__2].r, dabs(r__1)) + (r__2 = r_imag(&ap[ + kx]), dabs(r__2)) > rowmax) { + i__2 = kx; + rowmax = (r__1 = ap[i__2].r, dabs(r__1)) + (r__2 = + r_imag(&ap[kx]), dabs(r__2)); + jmax = j; + } + kx += j; +/* L20: */ + } + kpc = (imax - 1) * imax / 2 + 1; + if (imax > 1) { + i__1 = imax - 1; + jmax = icamax_(&i__1, &ap[kpc], &c__1); +/* Computing MAX */ + i__1 = kpc + jmax - 1; + r__3 = rowmax, r__4 = (r__1 = ap[i__1].r, dabs(r__1)) + ( + r__2 = r_imag(&ap[kpc + jmax - 1]), dabs(r__2)); + rowmax = dmax(r__3,r__4); + } + + if (absakk >= alpha * colmax * (colmax / rowmax)) { + +/* no interchange, use 1-by-1 pivot block */ + + kp = k; + } else /* if(complicated condition) */ { + i__1 = kpc + imax - 1; + if ((r__1 = ap[i__1].r, dabs(r__1)) + (r__2 = r_imag(&ap[ + kpc + imax - 1]), dabs(r__2)) >= alpha * rowmax) { + +/* interchange rows and columns K and IMAX, use 1-by-1 */ +/* pivot block */ + + kp = imax; + } else { + +/* interchange rows and columns K-1 and IMAX, use 2-by-2 */ +/* pivot block */ + + kp = imax; + kstep = 2; + } + } + } + + kk = k - kstep + 1; + if (kstep == 2) { + knc = knc - k + 1; + } + if (kp != kk) { + +/* Interchange rows and columns KK and KP in the leading */ +/* submatrix A(1:k,1:k) */ + + i__1 = kp - 1; + cswap_(&i__1, &ap[knc], &c__1, &ap[kpc], &c__1); + kx = kpc + kp - 1; + i__1 = kk - 1; + for (j = kp + 1; j <= i__1; ++j) { + kx = kx + j - 1; + i__2 = knc + j - 1; + t.r = ap[i__2].r, t.i = ap[i__2].i; + i__2 = knc + j - 1; + i__3 = kx; + ap[i__2].r = ap[i__3].r, ap[i__2].i = ap[i__3].i; + i__2 = kx; + ap[i__2].r = t.r, ap[i__2].i = t.i; +/* L30: */ + } + i__1 = knc + kk - 1; + t.r = ap[i__1].r, t.i = ap[i__1].i; + i__1 = knc + kk - 1; + i__2 = kpc + kp - 1; + ap[i__1].r = ap[i__2].r, ap[i__1].i = ap[i__2].i; + i__1 = kpc + kp - 1; + ap[i__1].r = t.r, ap[i__1].i = t.i; + if (kstep == 2) { + i__1 = kc + k - 2; + t.r = ap[i__1].r, t.i = ap[i__1].i; + i__1 = kc + k - 2; + i__2 = kc + kp - 1; + ap[i__1].r = ap[i__2].r, ap[i__1].i = ap[i__2].i; + i__1 = kc + kp - 1; + ap[i__1].r = t.r, ap[i__1].i = t.i; + } + } + +/* Update the leading submatrix */ + + if (kstep == 1) { + +/* 1-by-1 pivot block D(k): column k now holds */ + +/* W(k) = U(k)*D(k) */ + +/* where U(k) is the k-th column of U */ + +/* Perform a rank-1 update of A(1:k-1,1:k-1) as */ + +/* A := A - U(k)*D(k)*U(k)' = A - W(k)*1/D(k)*W(k)' */ + + c_div(&q__1, &c_b1, &ap[kc + k - 1]); + r1.r = q__1.r, r1.i = q__1.i; + i__1 = k - 1; + q__1.r = -r1.r, q__1.i = -r1.i; + cspr_(uplo, &i__1, &q__1, &ap[kc], &c__1, &ap[1]); + +/* Store U(k) in column k */ + + i__1 = k - 1; + cscal_(&i__1, &r1, &ap[kc], &c__1); + } else { + +/* 2-by-2 pivot block D(k): columns k and k-1 now hold */ + +/* ( W(k-1) W(k) ) = ( U(k-1) U(k) )*D(k) */ + +/* where U(k) and U(k-1) are the k-th and (k-1)-th columns */ +/* of U */ + +/* Perform a rank-2 update of A(1:k-2,1:k-2) as */ + +/* A := A - ( U(k-1) U(k) )*D(k)*( U(k-1) U(k) )' */ +/* = A - ( W(k-1) W(k) )*inv(D(k))*( W(k-1) W(k) )' */ + + if (k > 2) { + + i__1 = k - 1 + (k - 1) * k / 2; + d12.r = ap[i__1].r, d12.i = ap[i__1].i; + c_div(&q__1, &ap[k - 1 + (k - 2) * (k - 1) / 2], &d12); + d22.r = q__1.r, d22.i = q__1.i; + c_div(&q__1, &ap[k + (k - 1) * k / 2], &d12); + d11.r = q__1.r, d11.i = q__1.i; + q__3.r = d11.r * d22.r - d11.i * d22.i, q__3.i = d11.r * + d22.i + d11.i * d22.r; + q__2.r = q__3.r - 1.f, q__2.i = q__3.i - 0.f; + c_div(&q__1, &c_b1, &q__2); + t.r = q__1.r, t.i = q__1.i; + c_div(&q__1, &t, &d12); + d12.r = q__1.r, d12.i = q__1.i; + + for (j = k - 2; j >= 1; --j) { + i__1 = j + (k - 2) * (k - 1) / 2; + q__3.r = d11.r * ap[i__1].r - d11.i * ap[i__1].i, + q__3.i = d11.r * ap[i__1].i + d11.i * ap[i__1] + .r; + i__2 = j + (k - 1) * k / 2; + q__2.r = q__3.r - ap[i__2].r, q__2.i = q__3.i - ap[ + i__2].i; + q__1.r = d12.r * q__2.r - d12.i * q__2.i, q__1.i = + d12.r * q__2.i + d12.i * q__2.r; + wkm1.r = q__1.r, wkm1.i = q__1.i; + i__1 = j + (k - 1) * k / 2; + q__3.r = d22.r * ap[i__1].r - d22.i * ap[i__1].i, + q__3.i = d22.r * ap[i__1].i + d22.i * ap[i__1] + .r; + i__2 = j + (k - 2) * (k - 1) / 2; + q__2.r = q__3.r - ap[i__2].r, q__2.i = q__3.i - ap[ + i__2].i; + q__1.r = d12.r * q__2.r - d12.i * q__2.i, q__1.i = + d12.r * q__2.i + d12.i * q__2.r; + wk.r = q__1.r, wk.i = q__1.i; + for (i__ = j; i__ >= 1; --i__) { + i__1 = i__ + (j - 1) * j / 2; + i__2 = i__ + (j - 1) * j / 2; + i__3 = i__ + (k - 1) * k / 2; + q__3.r = ap[i__3].r * wk.r - ap[i__3].i * wk.i, + q__3.i = ap[i__3].r * wk.i + ap[i__3].i * + wk.r; + q__2.r = ap[i__2].r - q__3.r, q__2.i = ap[i__2].i + - q__3.i; + i__4 = i__ + (k - 2) * (k - 1) / 2; + q__4.r = ap[i__4].r * wkm1.r - ap[i__4].i * + wkm1.i, q__4.i = ap[i__4].r * wkm1.i + ap[ + i__4].i * wkm1.r; + q__1.r = q__2.r - q__4.r, q__1.i = q__2.i - + q__4.i; + ap[i__1].r = q__1.r, ap[i__1].i = q__1.i; +/* L40: */ + } + i__1 = j + (k - 1) * k / 2; + ap[i__1].r = wk.r, ap[i__1].i = wk.i; + i__1 = j + (k - 2) * (k - 1) / 2; + ap[i__1].r = wkm1.r, ap[i__1].i = wkm1.i; +/* L50: */ + } + + } + } + } + +/* Store details of the interchanges in IPIV */ + + if (kstep == 1) { + ipiv[k] = kp; + } else { + ipiv[k] = -kp; + ipiv[k - 1] = -kp; + } + +/* Decrease K and return to the start of the main loop */ + + k -= kstep; + kc = knc - k; + goto L10; + + } else { + +/* Factorize A as L*D*L' using the lower triangle of A */ + +/* K is the main loop index, increasing from 1 to N in steps of */ +/* 1 or 2 */ + + k = 1; + kc = 1; + npp = *n * (*n + 1) / 2; +L60: + knc = kc; + +/* If K > N, exit from loop */ + + if (k > *n) { + goto L110; + } + kstep = 1; + +/* Determine rows and columns to be interchanged and whether */ +/* a 1-by-1 or 2-by-2 pivot block will be used */ + + i__1 = kc; + absakk = (r__1 = ap[i__1].r, dabs(r__1)) + (r__2 = r_imag(&ap[kc]), + dabs(r__2)); + +/* IMAX is the row-index of the largest off-diagonal element in */ +/* column K, and COLMAX is its absolute value */ + + if (k < *n) { + i__1 = *n - k; + imax = k + icamax_(&i__1, &ap[kc + 1], &c__1); + i__1 = kc + imax - k; + colmax = (r__1 = ap[i__1].r, dabs(r__1)) + (r__2 = r_imag(&ap[kc + + imax - k]), dabs(r__2)); + } else { + colmax = 0.f; + } + + if (dmax(absakk,colmax) == 0.f) { + +/* Column K is zero: set INFO and continue */ + + if (*info == 0) { + *info = k; + } + kp = k; + } else { + if (absakk >= alpha * colmax) { + +/* no interchange, use 1-by-1 pivot block */ + + kp = k; + } else { + +/* JMAX is the column-index of the largest off-diagonal */ +/* element in row IMAX, and ROWMAX is its absolute value */ + + rowmax = 0.f; + kx = kc + imax - k; + i__1 = imax - 1; + for (j = k; j <= i__1; ++j) { + i__2 = kx; + if ((r__1 = ap[i__2].r, dabs(r__1)) + (r__2 = r_imag(&ap[ + kx]), dabs(r__2)) > rowmax) { + i__2 = kx; + rowmax = (r__1 = ap[i__2].r, dabs(r__1)) + (r__2 = + r_imag(&ap[kx]), dabs(r__2)); + jmax = j; + } + kx = kx + *n - j; +/* L70: */ + } + kpc = npp - (*n - imax + 1) * (*n - imax + 2) / 2 + 1; + if (imax < *n) { + i__1 = *n - imax; + jmax = imax + icamax_(&i__1, &ap[kpc + 1], &c__1); +/* Computing MAX */ + i__1 = kpc + jmax - imax; + r__3 = rowmax, r__4 = (r__1 = ap[i__1].r, dabs(r__1)) + ( + r__2 = r_imag(&ap[kpc + jmax - imax]), dabs(r__2)) + ; + rowmax = dmax(r__3,r__4); + } + + if (absakk >= alpha * colmax * (colmax / rowmax)) { + +/* no interchange, use 1-by-1 pivot block */ + + kp = k; + } else /* if(complicated condition) */ { + i__1 = kpc; + if ((r__1 = ap[i__1].r, dabs(r__1)) + (r__2 = r_imag(&ap[ + kpc]), dabs(r__2)) >= alpha * rowmax) { + +/* interchange rows and columns K and IMAX, use 1-by-1 */ +/* pivot block */ + + kp = imax; + } else { + +/* interchange rows and columns K+1 and IMAX, use 2-by-2 */ +/* pivot block */ + + kp = imax; + kstep = 2; + } + } + } + + kk = k + kstep - 1; + if (kstep == 2) { + knc = knc + *n - k + 1; + } + if (kp != kk) { + +/* Interchange rows and columns KK and KP in the trailing */ +/* submatrix A(k:n,k:n) */ + + if (kp < *n) { + i__1 = *n - kp; + cswap_(&i__1, &ap[knc + kp - kk + 1], &c__1, &ap[kpc + 1], + &c__1); + } + kx = knc + kp - kk; + i__1 = kp - 1; + for (j = kk + 1; j <= i__1; ++j) { + kx = kx + *n - j + 1; + i__2 = knc + j - kk; + t.r = ap[i__2].r, t.i = ap[i__2].i; + i__2 = knc + j - kk; + i__3 = kx; + ap[i__2].r = ap[i__3].r, ap[i__2].i = ap[i__3].i; + i__2 = kx; + ap[i__2].r = t.r, ap[i__2].i = t.i; +/* L80: */ + } + i__1 = knc; + t.r = ap[i__1].r, t.i = ap[i__1].i; + i__1 = knc; + i__2 = kpc; + ap[i__1].r = ap[i__2].r, ap[i__1].i = ap[i__2].i; + i__1 = kpc; + ap[i__1].r = t.r, ap[i__1].i = t.i; + if (kstep == 2) { + i__1 = kc + 1; + t.r = ap[i__1].r, t.i = ap[i__1].i; + i__1 = kc + 1; + i__2 = kc + kp - k; + ap[i__1].r = ap[i__2].r, ap[i__1].i = ap[i__2].i; + i__1 = kc + kp - k; + ap[i__1].r = t.r, ap[i__1].i = t.i; + } + } + +/* Update the trailing submatrix */ + + if (kstep == 1) { + +/* 1-by-1 pivot block D(k): column k now holds */ + +/* W(k) = L(k)*D(k) */ + +/* where L(k) is the k-th column of L */ + + if (k < *n) { + +/* Perform a rank-1 update of A(k+1:n,k+1:n) as */ + +/* A := A - L(k)*D(k)*L(k)' = A - W(k)*(1/D(k))*W(k)' */ + + c_div(&q__1, &c_b1, &ap[kc]); + r1.r = q__1.r, r1.i = q__1.i; + i__1 = *n - k; + q__1.r = -r1.r, q__1.i = -r1.i; + cspr_(uplo, &i__1, &q__1, &ap[kc + 1], &c__1, &ap[kc + *n + - k + 1]); + +/* Store L(k) in column K */ + + i__1 = *n - k; + cscal_(&i__1, &r1, &ap[kc + 1], &c__1); + } + } else { + +/* 2-by-2 pivot block D(k): columns K and K+1 now hold */ + +/* ( W(k) W(k+1) ) = ( L(k) L(k+1) )*D(k) */ + +/* where L(k) and L(k+1) are the k-th and (k+1)-th columns */ +/* of L */ + + if (k < *n - 1) { + +/* Perform a rank-2 update of A(k+2:n,k+2:n) as */ + +/* A := A - ( L(k) L(k+1) )*D(k)*( L(k) L(k+1) )' */ +/* = A - ( W(k) W(k+1) )*inv(D(k))*( W(k) W(k+1) )' */ + +/* where L(k) and L(k+1) are the k-th and (k+1)-th */ +/* columns of L */ + + i__1 = k + 1 + (k - 1) * ((*n << 1) - k) / 2; + d21.r = ap[i__1].r, d21.i = ap[i__1].i; + c_div(&q__1, &ap[k + 1 + k * ((*n << 1) - k - 1) / 2], & + d21); + d11.r = q__1.r, d11.i = q__1.i; + c_div(&q__1, &ap[k + (k - 1) * ((*n << 1) - k) / 2], &d21) + ; + d22.r = q__1.r, d22.i = q__1.i; + q__3.r = d11.r * d22.r - d11.i * d22.i, q__3.i = d11.r * + d22.i + d11.i * d22.r; + q__2.r = q__3.r - 1.f, q__2.i = q__3.i - 0.f; + c_div(&q__1, &c_b1, &q__2); + t.r = q__1.r, t.i = q__1.i; + c_div(&q__1, &t, &d21); + d21.r = q__1.r, d21.i = q__1.i; + + i__1 = *n; + for (j = k + 2; j <= i__1; ++j) { + i__2 = j + (k - 1) * ((*n << 1) - k) / 2; + q__3.r = d11.r * ap[i__2].r - d11.i * ap[i__2].i, + q__3.i = d11.r * ap[i__2].i + d11.i * ap[i__2] + .r; + i__3 = j + k * ((*n << 1) - k - 1) / 2; + q__2.r = q__3.r - ap[i__3].r, q__2.i = q__3.i - ap[ + i__3].i; + q__1.r = d21.r * q__2.r - d21.i * q__2.i, q__1.i = + d21.r * q__2.i + d21.i * q__2.r; + wk.r = q__1.r, wk.i = q__1.i; + i__2 = j + k * ((*n << 1) - k - 1) / 2; + q__3.r = d22.r * ap[i__2].r - d22.i * ap[i__2].i, + q__3.i = d22.r * ap[i__2].i + d22.i * ap[i__2] + .r; + i__3 = j + (k - 1) * ((*n << 1) - k) / 2; + q__2.r = q__3.r - ap[i__3].r, q__2.i = q__3.i - ap[ + i__3].i; + q__1.r = d21.r * q__2.r - d21.i * q__2.i, q__1.i = + d21.r * q__2.i + d21.i * q__2.r; + wkp1.r = q__1.r, wkp1.i = q__1.i; + i__2 = *n; + for (i__ = j; i__ <= i__2; ++i__) { + i__3 = i__ + (j - 1) * ((*n << 1) - j) / 2; + i__4 = i__ + (j - 1) * ((*n << 1) - j) / 2; + i__5 = i__ + (k - 1) * ((*n << 1) - k) / 2; + q__3.r = ap[i__5].r * wk.r - ap[i__5].i * wk.i, + q__3.i = ap[i__5].r * wk.i + ap[i__5].i * + wk.r; + q__2.r = ap[i__4].r - q__3.r, q__2.i = ap[i__4].i + - q__3.i; + i__6 = i__ + k * ((*n << 1) - k - 1) / 2; + q__4.r = ap[i__6].r * wkp1.r - ap[i__6].i * + wkp1.i, q__4.i = ap[i__6].r * wkp1.i + ap[ + i__6].i * wkp1.r; + q__1.r = q__2.r - q__4.r, q__1.i = q__2.i - + q__4.i; + ap[i__3].r = q__1.r, ap[i__3].i = q__1.i; +/* L90: */ + } + i__2 = j + (k - 1) * ((*n << 1) - k) / 2; + ap[i__2].r = wk.r, ap[i__2].i = wk.i; + i__2 = j + k * ((*n << 1) - k - 1) / 2; + ap[i__2].r = wkp1.r, ap[i__2].i = wkp1.i; +/* L100: */ + } + } + } + } + +/* Store details of the interchanges in IPIV */ + + if (kstep == 1) { + ipiv[k] = kp; + } else { + ipiv[k] = -kp; + ipiv[k + 1] = -kp; + } + +/* Increase K and return to the start of the main loop */ + + k += kstep; + kc = knc + *n - k + 2; + goto L60; + + } + +L110: + return 0; + +/* End of CSPTRF */ + +} /* csptrf_ */ |