git push -u origin main

synspec/extracted/matinv.f

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+      SUBROUTINE MATINV(A,N,NR)
+C     =========================
+C
+C     Matrix inversion
+C      by LU decomposition
+C
+C      A  -  matrix of actual size (N x N) and maximum size (NR x NR)
+C            to be inverted;
+C      Inversion is accomplished in place and the original matrix is
+C      replaced by its inverse
+C
+      INCLUDE 'PARAMS.FOR'
+      DIMENSION A(NR,NR)
+      IF(N.EQ.1) GO TO 250
+      DO 50 I=2,N
+         IM1=I-1
+         DO 20 J=1,IM1
+            JM1=J-1
+            DIV=A(J,J)
+            SUM=0.
+            IF(JM1.LT.1) GO TO 20
+            DO 10 K=1,JM1
+   10          SUM=SUM+A(I,K)*A(K,J)
+   20       A(I,J)=(A(I,J)-SUM)/DIV
+         DO 40 J=I,N
+            SUM=0.
+            DO 30 K=1,IM1
+   30          SUM=SUM+A(I,K)*A(K,J)
+   40       A(I,J)=A(I,J)-SUM
+   50 CONTINUE
+      DO 80 II=2,N
+         I=N+2-II
+         IM1=I-1
+         IF(IM1.LT.1) GO TO 80
+         DO 70 JJ=1,IM1
+            J=I-JJ
+            JP1=J+1
+            SUM=0.
+            IF(JP1.GT.IM1) GO TO 70
+            DO 60 K=JP1,IM1
+   60          SUM=SUM+A(I,K)*A(K,J)
+   70       A(I,J)=-A(I,J)-SUM
+   80 CONTINUE
+      DO 110 II=1,N
+         I=N+1-II
+         DIV=A(I,I)
+         IP1=I+1
+         IF(IP1.GT.N) GO TO 110
+         DO 100 JJ=IP1,N
+            J=N+IP1-JJ
+            SUM=0.
+            DO 90 K=IP1,J
+   90          SUM=SUM+A(I,K)*A(K,J)
+            A(I,J)=-SUM/DIV
+  100    CONTINUE
+  110 A(I,I)=1.0D0/A(I,I)
+C
+      DO 240 I=1,N
+         DO 230 J=1,N
+            K0=I
+            IF(J.GE.I) GO TO 220
+            SUM=0.
+  200       DO 210 K=K0,N
+  210          SUM=SUM+A(I,K)*A(K,J)
+            GO TO 230
+  220       K0=J
+            SUM=A(I,K0)
+            IF(K0.EQ.N) GO TO 230
+            K0=K0+1
+            GO TO 200
+  230    A(I,J)=SUM
+  240 CONTINUE
+      RETURN
+  250 A(1,1)=1.0D0/A(1,1)
+      RETURN
+      END