*DECK SCASUM FUNCTION SCASUM (N, CX, INCX) C***BEGIN PROLOGUE SCASUM C***PURPOSE Compute the sum of the magnitudes of the real and C imaginary elements of a complex vector. C***LIBRARY SLATEC (BLAS) C***CATEGORY D1A3A C***TYPE COMPLEX (SASUM-S, DASUM-D, SCASUM-C) C***KEYWORDS BLAS, LINEAR ALGEBRA, SUM OF MAGNITUDES OF A 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 SCASUM single precision result (zero if N .LE. 0) C C Returns sums of magnitudes of real and imaginary parts of C components of CX. Note that this is not the L1 norm of CX. C CASUM = sum from 0 to N-1 of ABS(REAL(CX(IX+I*INCX))) + C ABS(IMAG(CX(IX+I*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 890831 Modified array declarations. (WRB) C 890831 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 SCASUM COMPLEX CX(*) INTEGER I, INCX, IX, N C***FIRST EXECUTABLE STATEMENT SCASUM SCASUM = 0.0E0 IF (N .LE. 0) RETURN C IF (INCX .EQ. 1) GOTO 20 C C Code for increment not equal to 1. C IX = 1 IF (INCX .LT. 0) IX = (-N+1)*INCX + 1 DO 10 I = 1,N SCASUM = SCASUM + ABS(REAL(CX(IX))) + ABS(AIMAG(CX(IX))) IX = IX + INCX 10 CONTINUE RETURN C C Code for increment equal to 1. C 20 DO 30 I = 1,N SCASUM = SCASUM + ABS(REAL(CX(I))) + ABS(AIMAG(CX(I))) 30 CONTINUE RETURN END