You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
117 lines
3.5 KiB
117 lines
3.5 KiB
C Copyright(C) 1999-2021 National Technology & Engineering Solutions
|
|
C of Sandia, LLC (NTESS). Under the terms of Contract DE-NA0003525 with
|
|
C NTESS, the U.S. Government retains certain rights in this software.
|
|
C
|
|
C See packages/seacas/LICENSE for details
|
|
|
|
c
|
|
C
|
|
C C* FILE: [.QMESH]PICKM1.FOR
|
|
C C* MODIFIED BY: TED BLACKER
|
|
C C* MODIFICATION DATE: 7/6/90
|
|
C C* MODIFICATION: COMPLETED HEADER INFORMATION
|
|
C
|
|
SUBROUTINE PICKM1 (N, X, Y, ANGLE, M1, IFIRST, REAL)
|
|
C***********************************************************************
|
|
C
|
|
C SUBROUTINE PICKM1 = DETERMINES A REASONABLE SHAPE FOR A LOGICAL
|
|
C RECTANGLE WITH PERIMETER GIVEN IN X AND Y
|
|
C
|
|
C***********************************************************************
|
|
C
|
|
DIMENSION X (N), Y (N), ANGLE (N)
|
|
DIMENSION SMANG (7), INDEX (7)
|
|
C
|
|
LOGICAL REAL
|
|
C
|
|
C FORM THE LIST OF SMALLEST ANGLES
|
|
C
|
|
NSA = 6
|
|
DO 100 I = 1, NSA
|
|
SMANG (I) = 10.
|
|
INDEX (I) = 0
|
|
100 CONTINUE
|
|
C
|
|
PI = ATAN2(0.0, -1.0)
|
|
TWOPI = PI + PI
|
|
AGOLD = ATAN2 (Y (1) - Y (N), X (1) - X (N))
|
|
C
|
|
DO 130 J = 1, N
|
|
C
|
|
C GET THE ANGLE FORMED BY THIS SET OF POINTS
|
|
C
|
|
NEXT = J + 1
|
|
IF (NEXT .GT. N) NEXT = 1
|
|
AGNEW = ATAN2 (Y (NEXT) - Y (J) , X (NEXT) - X (J))
|
|
DIFF = AGNEW - AGOLD
|
|
IF (DIFF .GT. PI)DIFF = DIFF - TWOPI
|
|
IF (DIFF .LT. - PI)DIFF = DIFF + TWOPI
|
|
ANGLE (J) = PI - DIFF
|
|
AGOLD = AGNEW
|
|
C
|
|
C SORT THIS ANGLE AGAINST PREVIOUS ANGLES TO SEE IF IT IS ONE OF
|
|
C THE SMALLEST
|
|
C
|
|
SMANG (NSA + 1) = ANGLE (J)
|
|
INDEX (NSA + 1) = J
|
|
DO II = 1, NSA
|
|
I = NSA + 1 - II
|
|
IF (SMANG (I + 1) .GE. SMANG (I)) GO TO 120
|
|
TEMP = SMANG (I)
|
|
ITEMP = INDEX (I)
|
|
SMANG (I) = SMANG (I + 1)
|
|
INDEX (I) = INDEX (I + 1)
|
|
SMANG (I + 1) = TEMP
|
|
INDEX (I + 1) = ITEMP
|
|
end do
|
|
120 CONTINUE
|
|
C
|
|
130 CONTINUE
|
|
C
|
|
C DETERMINE OPTIMUM ORIGIN / SHAPE COMBINATION
|
|
C
|
|
ATOL = PI * 150. / 180.
|
|
IFIRST = 1
|
|
M1 = N / 4
|
|
M2 = N / 2 - M1
|
|
I2 = 1 + M1
|
|
I3 = I2 + M2
|
|
I4 = I3 + M1
|
|
GBEST = ANGLE (1) + ANGLE (I2) + ANGLE (I3) + ANGLE (I4)
|
|
BADANG = AMAX1 (ANGLE (1), ANGLE (I2), ANGLE (I3), ANGLE (I4))
|
|
C
|
|
MMAX = N / 2 - 1
|
|
AMAXEL = DBLE(N / 4) * DBLE( (N + 2) / 4)
|
|
DO 150 ISA = 1, NSA
|
|
IF (SMANG (ISA) .LE. ATOL) THEN
|
|
I1 = INDEX (ISA)
|
|
DO 140 M = 1, MMAX
|
|
M2 = N / 2 - M
|
|
I2 = I1 + M
|
|
IF (I2 .GT. N) I2 = I2 - N
|
|
I3 = I2 + M2
|
|
IF (I3 .GT. N) I3 = I3 - N
|
|
I4 = I3 + M
|
|
IF (I4 .GT. N) I4 = I4 - N
|
|
AFAC = ANGLE (I1) + ANGLE (I2) + ANGLE (I3) + ANGLE (I4)
|
|
ERAT = AMIN1 (AMAXEL / DBLE(M * M2) , 5.)
|
|
EFAC = (ERAT + 15.) / 16.
|
|
GVAL = AFAC * EFAC
|
|
IF (GVAL .LT. GBEST) THEN
|
|
BADANG = AMAX1 (ANGLE (I1), ANGLE (I2), ANGLE (I3),
|
|
& ANGLE (I4))
|
|
IFIRST = I1
|
|
M1 = M
|
|
GBEST = GVAL
|
|
ENDIF
|
|
140 CONTINUE
|
|
ENDIF
|
|
150 CONTINUE
|
|
IF ( (REAL) .AND. (BADANG .GT. 2.62)) THEN
|
|
CALL MESSAGE(' ** WARNING: CORNER (S) OF THE REGION HAVE **')
|
|
CALL MESSAGE(' ** LARGE ANGLES (> 150 DEGREES.) **')
|
|
CALL MESSAGE(' ** POORLY FORMED MESH MAY RESULT **')
|
|
ENDIF
|
|
C
|
|
RETURN
|
|
END
|
|
|