NUMAL Section 3.6.3

BEGIN SECTION : 3.6.3 (July, 1974)

AUTHOR: C.G. VAN DER LAAN.

INSTITUTE: MATHEMATICAL CENTRE.

RECEIVED: 730815.

BRIEF DESCRIPTION:

    COMKWD CALCULATES THE ROOTS OF A QUADRATIC EQUATION WITH COMPLEX
    COEFFICIENTS.

KEYWORDS:

    ZEROS,QUADRATIC EQUATION,POLYNOMIAL EQUATION,COMPLEX COEFFICIENTS.

CALLING SEQUENCE:

    THE HEADING OF THE PROCEDURE READS:
    "PROCEDURE"COMKWD(PR,PI,QR,QI,GR,GI,KR,KI);
    "VALUE"PR,PI,QR,QI;"REAL"PR,PI,QR,QI,GR,GI,KR,KI;
    "CODE" 34345;

    THE MEANING OF THE FORMAL PARAMETERS IS:
    PR,PI,QR,QI:<ARITHMETIC EXPRESSION>;
                ENTRY:PR,QR ARE THE REAL PARTS AND PI,QI ARE THE
                      IMAGINARY PARTS OF THE COEFFICIENTS OF THE
                      QUADRATIC EQUATION:
                      X**2-2*(PR+I*PI)*X-(QR+I*QI)=0;
    GR,GI,KR,KI:<VARIABLE>;
                EXIT:THE REAL PARTS AND THE IMAGINARY PARTS OF THE
                     DINOMIAL ARE DELIVERED IN GR,KR AND GI,KI,
                     RESPECTIVELY;MOREOVER,THE MODULUS OF GR+I*GI IS
                     GREATER OR EQUAL THE MODULUS OF KR+I*KI.

PROCEDURES USED:

    COMMUL=CP34341;
    COMDIV=CP34342;
    COMSQRT=CP34343.

LANGUAGE: ALGOL 60.

EXAMPLE OF USE:

"BEGIN""REAL"GR,GI,KR,KI;
COMKWD(-.1,.3,.11,.02,GR,GI,KR,KI);
OUTPUT(61,"(""("X**2-2(-.1+.3*I)*X-( .11+.02*I) HAS ROOTS")",/,
    -D.DD,+D.DD,"("*I")",/,
    -D.DD,+D.DD,"("*I")"")",GR,GI,KR,KI)
"END"

X**2-2(-.1+.3*I)*X-( .11+.02*I) HAS ROOTS
-0.30+0.40*I
 0.10+0.20*I

SOURCE TEXT(S):
"CODE" 34345;