Solves a system of linear equations with a UDU- or LDL-factored symmetric coefficient matrix using packed storage.
The routine solves for
Xthe system of linear equations
with a symmetric matrix
A, given the Bunch-Kaufman factorization of
Lare upper and lower packed triangular matrices with unit diagonal and
Dis a symmetric block-diagonal matrix. The system is solved with multiple right-hand sides stored in the columns of the matrix
B. You must supply the factor
L) and the array
ipivreturned by the factorization routine
- Must beCHARACTER*1.'U'or'L'.Indicates how the input matrixAhas been factored:If, the arrayuplo='U'apstores the packed factorUof the factorizationA=. IfU*D*UT, the arrayuplo='L'apstores the packed factorLof the factorizationA=.L*D*LT
- The order of matrixINTEGER.A;n≥0.
- The number of right-hand sides;INTEGER.nrhs≥0.
- INTEGER.Array, size at leastmax(1,. Then)ipivarray, as returned by?sptrf.