CGEFA(3F)
CGEFA - CGEFA factors a complex matrix by Gaussian elimination.
Showing IRIX 6.5.30 (default release). Unchanged since IRIX 6.5.
NAME CGEFA - CGEFA factors a complex matrix by Gaussian elimination. CGEFA is usually called by CGECO, but it can be called directly with a saving in time if RCOND is not needed. (Time for CGECO) = (1 + 9/N)*(Time for CGEFA) . SYNOPSYS SUBROUTINE CGEFA(A,LDA,N,IPVT,INFO) DESCRIPTION On Entry A COMPLEX(LDA, N) the matrix to be factored. LDA INTEGER the leading dimension of the array A . N INTEGER the order of the matrix A . On Return A an upper triangular matrix and the multipliers which were used to obtain it. The factorization can be written A = L*U where L is a product of permutation and unit lower triangular matrices and U is upper triangular. IPVT INTEGER(N) an integer vector of pivot indices. INFO INTEGER = 0 normal value. = K if U(K,K) .EQ. 0.0 . This is not an error condition for this subroutine, but it does indicate that CGESL or CGEDI will divide by zero if called. Use RCOND in CGECO for a reliable indication of singularity. LINPACK. This version dated 08/14/78 . Cleve Moler, University of New Mexico, Argonne National Lab. Subroutines and Functions BLAS CAXPY,CSCAL,ICAMAX Fortran ABS,AIMAG,REAL