49 lines
1.1 KiB
FortranFixed
49 lines
1.1 KiB
FortranFixed
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c****************************************************************
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subroutine matmat(r_a,r_b,r_c)
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c****************************************************************
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c**
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c** FILE NAME: matmat.for
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c**
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c** DATE WRITTEN: 8/3/90
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c**
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c** PROGRAMMER:Scott Hensley
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c**
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c** FUNCTIONAL DESCRIPTION: The subroutine takes two 3x3 matrices
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c** and multiplies them to return another 3x3 matrix.
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c**
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c** ROUTINES CALLED:none
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c**
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c** NOTES: none
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c**
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c** UPDATE LOG:
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c**
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c*****************************************************************
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implicit none
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c INPUT VARIABLES:
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real*8 r_a(3,3),r_b(3,3) !3x3 matrix
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c OUTPUT VARIABLES:
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real*8 r_c(3,3) !3x3 matrix
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c LOCAL VARIABLES:
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integer i
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c PROCESSING STEPS:
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c compute matrix product
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do i=1,3
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r_c(i,1) = r_a(i,1)*r_b(1,1) + r_a(i,2)*r_b(2,1) +
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+ r_a(i,3)*r_b(3,1)
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r_c(i,2) = r_a(i,1)*r_b(1,2) + r_a(i,2)*r_b(2,2) +
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+ r_a(i,3)*r_b(3,2)
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r_c(i,3) = r_a(i,1)*r_b(1,3) + r_a(i,2)*r_b(2,3) +
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+ r_a(i,3)*r_b(3,3)
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enddo
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end
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