public class Sspsv
- extends java.lang.Object
Following is the description from the original
Fortran source. For each array argument, the Java
version will include an integer offset parameter, so
the arguments may not match the description exactly.
Contact email@example.com with any questions.
* SSPSV computes the solution to a real system of linear equations
* A * X = B,
* where A is an N-by-N symmetric matrix stored in packed format 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, 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.
* UPLO (input) CHARACTER*1
* = 'U': Upper triangle of A is stored;
* = 'L': Lower triangle of A is stored.
* N (input) INTEGER
* The number of linear equations, i.e., the order of the
* matrix A. N >= 0.
* NRHS (input) INTEGER
* The number of right hand sides, i.e., the number of columns
* of the matrix B. NRHS >= 0.
* AP (input/output) REAL 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.
* See below for further details.
* On exit, 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 SSPTRF, stored as
* a packed triangular matrix in the same storage format as A.
* IPIV (output) INTEGER array, dimension (N)
* Details of the interchanges and the block structure of D, as
* determined by SSPTRF. 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.
* B (input/output) REAL array, 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.
* LDB (input) INTEGER
* The leading dimension of the array B. LDB >= max(1,N).
* 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, so the solution could not be
* Further Details
* The packed storage scheme is illustrated by the following example
* when N = 4, UPLO = 'U':
* Two-dimensional storage of the symmetric matrix A:
* a11 a12 a13 a14
* a22 a23 a24
* a33 a34 (aij = aji)
* Packed storage of the upper triangle of A:
* AP = [ a11, a12, a22, a13, a23, a33, a14, a24, a34, a44 ]
* .. External Functions ..
|Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
public static void sspsv(java.lang.String uplo,