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SUBROUTINE STRCO(T,LDT,N,RCOND,Z,JOB)
INTEGER LDT,N,JOB
REAL T(LDT,1),Z(1)
REAL RCOND
C
C STRCO ESTIMATES THE CONDITION OF A REAL TRIANGULAR MATRIX.
C
C ON ENTRY
C
C T REAL(LDT,N)
C T CONTAINS THE TRIANGULAR MATRIX. THE ZERO
C ELEMENTS OF THE MATRIX ARE NOT REFERENCED, AND
C THE CORRESPONDING ELEMENTS OF THE ARRAY CAN BE
C USED TO STORE OTHER INFORMATION.
C
C LDT INTEGER
C LDT IS THE LEADING DIMENSION OF THE ARRAY T.
C
C N INTEGER
C N IS THE ORDER OF THE SYSTEM.
C
C JOB INTEGER
C = 0 T IS LOWER TRIANGULAR.
C = NONZERO T IS UPPER TRIANGULAR.
C
C ON RETURN
C
C RCOND REAL
C AN ESTIMATE OF THE RECIPROCAL CONDITION OF T .
C FOR THE SYSTEM T*X = B , RELATIVE PERTURBATIONS
C IN T AND B OF SIZE EPSILON MAY CAUSE
C RELATIVE PERTURBATIONS IN X OF SIZE EPSILON/RCOND
C IF RCOND IS SO SMALL THAT THE LOGICAL EXPRESSION
C 1.0 + RCOND .EQ. 1.0
C IS TRUE, THEN T MAY BE SINGULAR TO WORKING
C PRECISION. IN PARTICULAR, RCOND IS ZERO IF
C EXACT SINGULARITY IS DETECTED OR THE ESTIMATE
C UNDERFLOWS.
C
C Z REAL(N)
C A WORK VECTOR WHOSE CONTENTS ARE USUALLY UNIMPORTANT
C IF T IS CLOSE TO A SINGULAR MATRIX, THEN Z IS
C AN APPROXIMATE NULL VECTOR IN THE SENSE THAT
C NORM(A*Z) = RCOND*NORM(A)*NORM(Z) .
C
C LINPACK. THIS VERSION DATED 08/14/78 .
C CLEVE MOLER, UNIVERSITY OF NEW MEXICO, ARGONNE NATIONAL LAB.
C
C SUBROUTINES AND FUNCTIONS
C
C BLAS SAXPY,SSCAL,SASUM
C FORTRAN ABS,AMAX1,SIGN
C