      SUBROUTINE CHRM1(C,PN,UN)
C
C  ROUTINE FOR THE COMPUTATION OF THE ELEMENTS OF THE CHRISTOFFEL
C  MATRIX FOR AN ARBITRARY ANISOTROPIC MEDIUM
C
      DIMENSION C(3,3),PN(3),UN(3)
      COMMON /APROX/ A11,A12,A13,A14,A15,A16,A22,A23,A24,A25,A26,A33,
     1               A34,A35,A36,A44,A45,A46,A55,A56,A66,
     1               DXA11,DXA12,DXA13,DXA14,DXA15,DXA16,DXA22,DXA23,
     1               DXA24,DXA25,DXA26,DXA33,DXA34,DXA35,DXA36,DXA44,
     1               DXA45,DXA46,DXA55,DXA56,DXA66,
     1               DYA11,DYA12,DYA13,DYA14,DYA15,DYA16,DYA22,DYA23,
     1               DYA24,DYA25,DYA26,DYA33,DYA34,DYA35,DYA36,DYA44,
     1               DYA45,DYA46,DYA55,DYA56,DYA66,
     1               DZA11,DZA12,DZA13,DZA14,DZA15,DZA16,DZA22,DZA23,
     1               DZA24,DZA25,DZA26,DZA33,DZA34,DZA35,DZA36,DZA44,
     1               DZA45,DZA46,DZA55,DZA56,DZA66,
     1               A2546,A1266,A1355,A1456,A3645,A2344
C
      P1=PN(1)
      P2=PN(2)
      P3=PN(3)
      U1=UN(1)
      U2=UN(2)
      U3=UN(3)
      P2U3=P2*U3
      P3U2=P3*U2
      P1U2=P1*U2
      P2U1=P2*U1
      P1U3=P1*U3
      P3U1=P3*U1
      P1U1=P1*U1
      P2U2=P2*U2
      P3U3=P3*U3
      C(1,1)=P1U1*A11+P2U2*A66+P3U3*A55
     1+(P2U3+P3U2)*A56+(P1U3+P3U1)*A15+(P1U2+P2U1)*A16
      C(2,2)=P1U1*A66+P2U2*A22+P3U3*A44
     1+(P2U3+P3U2)*A24+(P1U3+P3U1)*A46+(P1U2+P2U1)*A26
      C(3,3)=P1U1*A55+P2U2*A44+P3U3*A33
     1+(P2U3+P3U2)*A34+(P1U3+P3U1)*A35+(P1U2+P2U1)*A45
      C(2,3)=P1U1*A56+P2U2*A24+P3U3*A34
     1+0.5*((P2U3+P3U2)*A2344+(P1U3+P3U1)*A3645+(P1U2+P2U1)*A2546)
      C(1,3)=P1U1*A15+P2U2*A46+P3U3*A35
     1+0.5*((P2U3+P3U2)*A3645+(P1U3+P3U1)*A1355+(P1U2+P2U1)*A1456)
      C(1,2)=P1U1*A16+P2U2*A26+P3U3*A45
     1+0.5*((P2U3+P3U2)*A2546+(P1U3+P3U1)*A1456+(P1U2+P2U1)*A1266)
      C(2,1)=C(1,2)
      C(3,2)=C(2,3)
      C(3,1)=C(1,3)
      RETURN
      END
