sysv#

Functions

void ssysv(
    const char*          uplo,
    const INT            n,
    const INT            nrhs,
          f32*  restrict A,
    const INT            lda,
          INT*  restrict ipiv,
          f32*  restrict B,
    const INT            ldb,
          f32*  restrict work,
    const INT            lwork,
          INT*           info
);
void ssysv(const char *uplo, const INT n, const INT nrhs, f32 *restrict A, const INT lda, INT *restrict ipiv, f32 *restrict B, const INT ldb, f32 *restrict work, const INT lwork, INT *info)#

SSYSV computes the solution to a real system of linear equations A * X = B, where A is an N-by-N symmetric matrix and X and B are N-by-NRHS matrices.

The diagonal pivoting method is used to factor A as A = U * D * U**T, if UPLO = ‘U’, or A = L * D * L**T, if UPLO = ‘L’, 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. The factored form of A is then used to solve the system of equations A * X = B.

Parameters

in
uplo

  • 'U': Upper triangle of A is stored

  • 'L': Lower triangle of A is stored

in
n

The number of linear equations, i.e., the order of the matrix A. n>=0.

in
nrhs

The number of right hand sides, i.e., the number of columns of the matrix B. nrhs>=0.

inout
A

Array of dimension (lda,n). On entry, the symmetric matrix A. If uplo='U', the leading n-by-n upper triangular part of A contains the upper triangular part of the matrix A, and the strictly lower triangular part of A is not referenced. If uplo='L', the leading n-by-n lower triangular part of A contains the lower triangular part of the matrix A, and the strictly upper triangular part of A is not referenced. On exit, if info=0, the block diagonal matrix D and the multipliers used to obtain the factor U or L from the factorization A = U*D*U**T or A = L*D*L**T as computed by ssytrf.

in
lda

The leading dimension of the array A. lda>=max(1,n).

out
ipiv

Array of dimension n. Pivot indices (0-based). If ipiv[k]>=0: rows/columns k and ipiv[k] were interchanged, D(k,k) is a 1-by-1 block. If ipiv[k]<0 (upper): rows/columns k-1 and -ipiv[k]-1 were interchanged, D(k-1:k,k-1:k) is a 2-by-2 block, and ipiv[k-1]=ipiv[k]. If ipiv[k]<0 (lower): rows/columns k+1 and -ipiv[k]-1 were interchanged, D(k:k+1,k:k+1) is a 2-by-2 block, and ipiv[k+1]=ipiv[k].

inout
B

Array of dimension (ldb,nrhs). On entry, the n-by-nrhs right hand side matrix B. On exit, if info=0, the n-by-nrhs solution matrix X.

in
ldb

The leading dimension of the array B. ldb>=max(1,n).

out
work

Array of dimension max(1,lwork). On exit, if info=0, work[0] returns the optimal lwork.

in
lwork

The length of work. lwork>=1, and for best performance lwork>=n*nb, where nb is the optimal block size for ssytrf. For lwork<n, TRS will be done with Level BLAS 2; for lwork>=n, TRS will be done with Level BLAS 3. If lwork=-1, then a workspace query is assumed; the routine only calculates the optimal size of the work array, returns this value as the first entry of the work array, and no error message related to lwork is issued.

out
info

  • info=0: successful exit

  • info<0: if info=-i, the i-th argument had an illegal value

  • info>0: if info=i, D(i,i) is exactly zero. The factorization has been completed, but the block diagonal matrix D is exactly singular, so the solution could not be computed.

Functions

void dsysv(
    const char*          uplo,
    const INT            n,
    const INT            nrhs,
          f64*  restrict A,
    const INT            lda,
          INT*  restrict ipiv,
          f64*  restrict B,
    const INT            ldb,
          f64*  restrict work,
    const INT            lwork,
          INT*           info
);
void dsysv(const char *uplo, const INT n, const INT nrhs, f64 *restrict A, const INT lda, INT *restrict ipiv, f64 *restrict B, const INT ldb, f64 *restrict work, const INT lwork, INT *info)#

DSYSV computes the solution to a real system of linear equations A * X = B, where A is an N-by-N symmetric matrix and X and B are N-by-NRHS matrices.

The diagonal pivoting method is used to factor A as A = U * D * U**T, if UPLO = ‘U’, or A = L * D * L**T, if UPLO = ‘L’, 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. The factored form of A is then used to solve the system of equations A * X = B.

Parameters

in
uplo

  • 'U': Upper triangle of A is stored

  • 'L': Lower triangle of A is stored

in
n

The number of linear equations, i.e., the order of the matrix A. n>=0.

in
nrhs

The number of right hand sides, i.e., the number of columns of the matrix B. nrhs>=0.

inout
A

Array of dimension (lda,n). On entry, the symmetric matrix A. If uplo='U', the leading n-by-n upper triangular part of A contains the upper triangular part of the matrix A, and the strictly lower triangular part of A is not referenced. If uplo='L', the leading n-by-n lower triangular part of A contains the lower triangular part of the matrix A, and the strictly upper triangular part of A is not referenced. On exit, if info=0, the block diagonal matrix D and the multipliers used to obtain the factor U or L from the factorization A = U*D*U**T or A = L*D*L**T as computed by dsytrf.

in
lda

The leading dimension of the array A. lda>=max(1,n).

out
ipiv

Array of dimension n. Pivot indices (0-based). If ipiv[k]>=0: rows/columns k and ipiv[k] were interchanged, D(k,k) is a 1-by-1 block. If ipiv[k]<0 (upper): rows/columns k-1 and -ipiv[k]-1 were interchanged, D(k-1:k,k-1:k) is a 2-by-2 block, and ipiv[k-1]=ipiv[k]. If ipiv[k]<0 (lower): rows/columns k+1 and -ipiv[k]-1 were interchanged, D(k:k+1,k:k+1) is a 2-by-2 block, and ipiv[k+1]=ipiv[k].

inout
B

Array of dimension (ldb,nrhs). On entry, the n-by-nrhs right hand side matrix B. On exit, if info=0, the n-by-nrhs solution matrix X.

in
ldb

The leading dimension of the array B. ldb>=max(1,n).

out
work

Array of dimension max(1,lwork). On exit, if info=0, work[0] returns the optimal lwork.

in
lwork

The length of work. lwork>=1, and for best performance lwork>=n*nb, where nb is the optimal block size for dsytrf. For lwork<n, TRS will be done with Level BLAS 2; for lwork>=n, TRS will be done with Level BLAS 3. If lwork=-1, then a workspace query is assumed; the routine only calculates the optimal size of the work array, returns this value as the first entry of the work array, and no error message related to lwork is issued.

out
info

  • info=0: successful exit

  • info<0: if info=-i, the i-th argument had an illegal value

  • info>0: if info=i, D(i,i) is exactly zero. The factorization has been completed, but the block diagonal matrix D is exactly singular, so the solution could not be computed.

Functions

void csysv(
    const char*          uplo,
    const INT            n,
    const INT            nrhs,
          c64*  restrict A,
    const INT            lda,
          INT*  restrict ipiv,
          c64*  restrict B,
    const INT            ldb,
          c64*  restrict work,
    const INT            lwork,
          INT*           info
);
void csysv(const char *uplo, const INT n, const INT nrhs, c64 *restrict A, const INT lda, INT *restrict ipiv, c64 *restrict B, const INT ldb, c64 *restrict work, const INT lwork, INT *info)#

CSYSV computes the solution to a complex system of linear equations A * X = B, where A is an N-by-N symmetric matrix and X and B are N-by-NRHS matrices.

The diagonal pivoting method is used to factor A as A = U * D * U**T, if UPLO = ‘U’, or A = L * D * L**T, if UPLO = ‘L’, 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. The factored form of A is then used to solve the system of equations A * X = B.

Parameters

in
uplo

  • 'U': Upper triangle of A is stored

  • 'L': Lower triangle of A is stored

in
n

The number of linear equations, i.e., the order of the matrix A. n>=0.

in
nrhs

The number of right hand sides, i.e., the number of columns of the matrix B. nrhs>=0.

inout
A

Complex array of dimension (lda,n). On entry, the symmetric matrix A. If uplo='U', the leading n-by-n upper triangular part of A contains the upper triangular part of the matrix A, and the strictly lower triangular part of A is not referenced. If uplo='L', the leading n-by-n lower triangular part of A contains the lower triangular part of the matrix A, and the strictly upper triangular part of A is not referenced. On exit, if info=0, the block diagonal matrix D and the multipliers used to obtain the factor U or L from the factorization A = U*D*U**T or A = L*D*L**T as computed by csytrf.

in
lda

The leading dimension of the array A. lda>=max(1,n).

out
ipiv

Array of dimension n. Pivot indices (0-based). If ipiv[k]>=0: rows/columns k and ipiv[k] were interchanged, D(k,k) is a 1-by-1 block. If ipiv[k]<0 (upper): rows/columns k-1 and -ipiv[k]-1 were interchanged, D(k-1:k,k-1:k) is a 2-by-2 block, and ipiv[k-1]=ipiv[k]. If ipiv[k]<0 (lower): rows/columns k+1 and -ipiv[k]-1 were interchanged, D(k:k+1,k:k+1) is a 2-by-2 block, and ipiv[k+1]=ipiv[k].

inout
B

Complex array of dimension (ldb,nrhs). On entry, the n-by-nrhs right hand side matrix B. On exit, if info=0, the n-by-nrhs solution matrix X.

in
ldb

The leading dimension of the array B. ldb>=max(1,n).

out
work

Complex array of dimension max(1,lwork). On exit, if info=0, work[0] returns the optimal lwork.

in
lwork

The length of work. lwork>=1, and for best performance lwork>=n*nb, where nb is the optimal block size for csytrf. For lwork<n, TRS will be done with Level BLAS 2; for lwork>=n, TRS will be done with Level BLAS 3. If lwork=-1, then a workspace query is assumed; the routine only calculates the optimal size of the work array, returns this value as the first entry of the work array, and no error message related to lwork is issued by XERBLA.

out
info

  • = 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, so the solution could not be computed.

Functions

void zsysv(
    const char*          uplo,
    const INT            n,
    const INT            nrhs,
          c128* restrict A,
    const INT            lda,
          INT*  restrict ipiv,
          c128* restrict B,
    const INT            ldb,
          c128* restrict work,
    const INT            lwork,
          INT*           info
);
void zsysv(const char *uplo, const INT n, const INT nrhs, c128 *restrict A, const INT lda, INT *restrict ipiv, c128 *restrict B, const INT ldb, c128 *restrict work, const INT lwork, INT *info)#

ZSYSV computes the solution to a complex system of linear equations A * X = B, where A is an N-by-N symmetric matrix and X and B are N-by-NRHS matrices.

The diagonal pivoting method is used to factor A as A = U * D * U**T, if UPLO = ‘U’, or A = L * D * L**T, if UPLO = ‘L’, 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. The factored form of A is then used to solve the system of equations A * X = B.

Parameters

in
uplo

  • 'U': Upper triangle of A is stored

  • 'L': Lower triangle of A is stored

in
n

The number of linear equations, i.e., the order of the matrix A. n>=0.

in
nrhs

The number of right hand sides, i.e., the number of columns of the matrix B. nrhs>=0.

inout
A

Complex array of dimension (lda,n). On entry, the symmetric matrix A. If uplo='U', the leading n-by-n upper triangular part of A contains the upper triangular part of the matrix A, and the strictly lower triangular part of A is not referenced. If uplo='L', the leading n-by-n lower triangular part of A contains the lower triangular part of the matrix A, and the strictly upper triangular part of A is not referenced. On exit, if info=0, the block diagonal matrix D and the multipliers used to obtain the factor U or L from the factorization A = U*D*U**T or A = L*D*L**T as computed by zsytrf.

in
lda

The leading dimension of the array A. lda>=max(1,n).

out
ipiv

Array of dimension n. Pivot indices (0-based). If ipiv[k]>=0: rows/columns k and ipiv[k] were interchanged, D(k,k) is a 1-by-1 block. If ipiv[k]<0 (upper): rows/columns k-1 and -ipiv[k]-1 were interchanged, D(k-1:k,k-1:k) is a 2-by-2 block, and ipiv[k-1]=ipiv[k]. If ipiv[k]<0 (lower): rows/columns k+1 and -ipiv[k]-1 were interchanged, D(k:k+1,k:k+1) is a 2-by-2 block, and ipiv[k+1]=ipiv[k].

inout
B

Complex array of dimension (ldb,nrhs). On entry, the n-by-nrhs right hand side matrix B. On exit, if info=0, the n-by-nrhs solution matrix X.

in
ldb

The leading dimension of the array B. ldb>=max(1,n).

out
work

Complex array of dimension max(1,lwork). On exit, if info=0, work[0] returns the optimal lwork.

in
lwork

The length of work. lwork>=1, and for best performance lwork>=n*nb, where nb is the optimal block size for zsytrf. For lwork<n, TRS will be done with Level BLAS 2; for lwork>=n, TRS will be done with Level BLAS 3. If lwork=-1, then a workspace query is assumed; the routine only calculates the optimal size of the work array, returns this value as the first entry of the work array, and no error message related to lwork is issued by XERBLA.

out
info

  • = 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, so the solution could not be computed.