Initial revision

difrac/params.f

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+C-----------------------------------------------------------------------
+C  To extract real or reciprocal cell parameters from the metric
+C  tensor G into ABC and ANG
+C-----------------------------------------------------------------------
+      SUBROUTINE PARAMS (G,ABC,ANG)
+      DIMENSION G(3,3),ABC(3),ANG(3)
+      DEG = 57.2958
+      DO 100 I = 1,3
+        ABC(I) = SQRT(G(I,I))
+  100 CONTINUE
+      P = G(2,3)/(ABC(2)*ABC(3))
+      Q = SQRT(1.0 - P*P)
+      ANG(1) = DEG*ATAN2(Q,P)
+      P = G(1,3)/(ABC(1)*ABC(3))
+      Q = SQRT(1.0 - P*P)
+      ANG(2) = DEG*ATAN2(Q,P)
+      P = G(1,2)/(ABC(1)*ABC(2))
+      Q = SQRT(1.0 - P*P)
+      ANG(3) = DEG*ATAN2(Q,P)
+      RETURN
+      END