SOLVEQ 
CALCKDQ 
QREG ION 
SREG ION 
CS 
CETC 
Note I. 
Note II. 
This subroutine calculates the shoreline for one time step assuming a 
previous shoreline (and shoreline angle = tan7! (dy/ax)) and diffrac- 
tion coefficients as calculated in subroutine CALCKDQ. The scheme is 
essentially as is described in Section 2. The matrix inversion is 
achieved using a standard algorithm for tridiagonal matrices. 
This routine calculates the diffraction coefficient and incoming wave 
angle a = a(x) in the diffraction zone using the theory of Penny and 
Price (1952) for both incoming wave directions (the angle convention 
is shown in subroutine INPUTQ). 
Calculates diffraction in the ''Q'" region. 
Calculates diffraction in the "'S'" region. 
Calculates complex valued Fresnel integral. 
Calculates a given depth and period. 
In subroutine EVOLVEQ 
L1 = Ist year index 
L2 = last year index 
Calculation 
begins at date: year (Ll), month (L1), hour (L1) 
ends at date: year (L2+1), month (L2+1), hour (L2+1) 
In a general program 
L1 = 
L2 = ND-1 where ND is defined in subroutine INPUTQ ND must be 
passed to subroutine EVOLVEQ. 
Program as given in this report is set up to allow complete bypassing 
(lost offshore) when waves are not diffracted, i.e., 
To change program for no bypassing, four statements must be changed 
in subroutine SOLVEQ. 
2 statements after 1001 
change QOLD (N1P1) 
to QOLD (N1PT) 
(1-ID) x QOLD (N1P2) 
0 
1 statement after 1001 
change QOLD (N1) = (ID-1) x QOLD (N1M1) 
to QOLD (N1) = 0 
1 statement after 3000 
change P(N1) = 1. - (1D-1) x Q(N1M1) 
to P(N1) = 1 
3 statements after 3000 
change Q(N1P1) = 0 + (2-ID)/P(N1P1) 
to Q(N1P1) = 0 
65 
