icamax.f
INTEGER FUNCTION ICAMAX (N, CX, INCX)
C***BEGIN PROLOGUE ICAMAX
C***PURPOSE Find the smallest index of the component of a complex
C vector having the maximum sum of magnitudes of real
C and imaginary parts.
C***LIBRARY SLATEC (BLAS)
C***CATEGORY D1A2
C***TYPE COMPLEX (ISAMAX-S, IDAMAX-D, ICAMAX-C)
C***KEYWORDS BLAS, LINEAR ALGEBRA, MAXIMUM COMPONENT, VECTOR
C***AUTHOR Lawson, C. L., (JPL)
C Hanson, R. J., (SNLA)
C Kincaid, D. R., (U. of Texas)
C Krogh, F. T., (JPL)
C***DESCRIPTION
C
C B L A S Subprogram
C Description of Parameters
C
C --Input--
C N number of elements in input vector(s)
C CX complex vector with N elements
C INCX storage spacing between elements of CX
C
C --Output--
C ICAMAX smallest index (zero if N .LE. 0)
C
C Returns the smallest index of the component of CX having the
C largest sum of magnitudes of real and imaginary parts.
C ICAMAX = first I, I = 1 to N, to maximize
C ABS(REAL(CX(IX+(I-1)*INCX))) + ABS(IMAG(CX(IX+(I-1)*INCX))),
C where IX = 1 if INCX .GE. 0, else IX = 1+(1-N)*INCX.
C
C***REFERENCES C. L. Lawson, R. J. Hanson, D. R. Kincaid and F. T.
C Krogh, Basic linear algebra subprograms for Fortran
C usage, Algorithm No. 539, Transactions on Mathematical
C Software 5, 3 (September 1979), pp. 308-323.
C***ROUTINES CALLED (NONE)
C***REVISION HISTORY (YYMMDD)
C 791001 DATE WRITTEN
C 861211 REVISION DATE from Version 3.2
C 891214 Prologue converted to Version 4.0 format. (BAB)
C 900821 Modified to correct problem with a negative increment.
C (WRB)
C 920501 Reformatted the REFERENCES section. (WRB)
C***END PROLOGUE ICAMAX