SUBROUTINE ORTRAN(NM,N,LOW,IGH,A,ORT,Z) C***BEGIN PROLOGUE ORTRAN C***DATE WRITTEN 760101 (YYMMDD) C***REVISION DATE 830518 (YYMMDD) C***CATEGORY NO. D4C4 C***KEYWORDS EIGENVALUES,EIGENVECTORS,EISPACK C***AUTHOR SMITH, B. T., ET AL. C***PURPOSE Accumulates orthogonal similarity transformations in C reduction of real general matrix by ORTHES. C***DESCRIPTION C C This subroutine is a translation of the ALGOL procedure ORTRANS, C NUM. MATH. 16, 181-204(1970) by Peters and Wilkinson. C HANDBOOK FOR AUTO. COMP., VOL.II-LINEAR ALGEBRA, 372-395(1971). C C This subroutine accumulates the orthogonal similarity C transformations used in the reduction of a REAL GENERAL C matrix to upper Hessenberg form by ORTHES. C C On INPUT C C NM must be set to the row dimension of two-dimensional C array parameters as declared in the calling program C dimension statement. C C N is the order of the matrix. C C LOW and IGH are integers determined by the balancing C subroutine BALANC. If BALANC has not been used, C set LOW=1, IGH=N. C C A contains information about the orthogonal trans- C formations used in the reduction by ORTHES C in its strict lower triangle. C C ORT contains further information about the trans- C formations used in the reduction by ORTHES. C only elements LOW through IGH are USED. C C On OUTPUT C C Z contains the transformation matrix produced in the C reduction by ORTHES. C C ORT has been altered. C C Questions and comments should be directed to B. S. Garbow, C APPLIED MATHEMATICS DIVISION, ARGONNE NATIONAL LABORATORY C ------------------------------------------------------------------ C***REFERENCES B. T. SMITH, J. M. BOYLE, J. J. DONGARRA, B. S. GARBOW, C Y. IKEBE, V. C. KLEMA, C. B. MOLER, *MATRIX EIGEN- C SYSTEM ROUTINES - EISPACK GUIDE*, SPRINGER-VERLAG, C 1976. C***ROUTINES CALLED (NONE) C***END PROLOGUE ORTRAN