Cloned SEACAS for EXODUS library with extra build files for internal package management.
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C Copyright(C) 1999-2020 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
SUBROUTINE QAAVAL (MXND, NODES, ANGLES, QRAT, AREA, XN, YN, CAREA)
C***********************************************************************
C SUBROUTINE QAAVAL = CALCULATES THE INTERIOR ANGLES OF A QUAD AND
C THE RATIO OF LARGEST TO SMALLEST ANGLE
C***********************************************************************
C VARIABLES USED:
C NODES = THE FOUR NODES OF THE ELEMENT IN CCW ORDER
C ANGLES = THE FOUR INTERIOR ANGLES IN THE ORDER 4-1, 1-2, 2-3, 3-4
C QRAT = THE RATIO OF THE LARGEST TO THE SMALLEST ANGLE
C CAREA = .TRUE. IF THE AREA IS TO BE CALCULATED
C AREA = ELEMENT'S AREA
C***********************************************************************
DIMENSION NODES (4), ANGLES (4), AG (4), XN (MXND), YN (MXND)
LOGICAL CAREA
PI = ATAN2(0.0, -1.0)
TWOPI = PI + PI
IF (CAREA) THEN
N1 = NODES (1)
N2 = NODES (2)
N3 = NODES (3)
N4 = NODES (4)
AREA = 0.5 * ( (XN (N3) - XN (N1)) * (YN (N4) - YN (N2))
& - (YN (N3) - YN (N1)) * (XN (N4) - XN (N2)))
ENDIF
DO 100 I = 1, 4
IF (I .EQ. 4) THEN
J = 1
ELSE
J = I + 1
ENDIF
N1 = NODES (I)
N2 = NODES (J)
IF ( (XN (N2) .EQ. XN (N1)) .AND. (YN (N2) .EQ. YN (N1))) THEN
QRAT = 1.E + 10
RETURN
ELSE
AG (J) = ATAN2 (YN (N2) - YN (N1), XN (N2) - XN (N1))
ENDIF
100 CONTINUE
DO 110 J = 1, 4
IF (J .EQ. 1) THEN
I = 4
ELSE
I = J - 1
ENDIF
DIFF = AG (J) - AG (I)
IF (DIFF .GT. PI) THEN
DIFF = DIFF - TWOPI
ELSEIF (DIFF .LT. - PI) THEN
DIFF = DIFF + TWOPI
ENDIF
ANGLES (J) = PI - DIFF
110 CONTINUE
QMIN = ANGLES (1)
QMAX = ANGLES (1)
DO 120 I = 2, 4
QMIN = AMIN1 (QMIN, ANGLES (I))
QMAX = AMAX1 (QMAX, ANGLES (I))
120 CONTINUE
IF (QMIN .GT. 0.) THEN
QRAT = QMAX / QMIN
ELSE
QRAT = 1.0E10
ENDIF
RETURN
END