Help calling in function

[jecstir2112]

Hey, Im trying to call the function into the matrix in order to multiply it by another matrices. I am having trouble with the reals and basics. I have the formats down ( i think )....


PROGRAM MATRIXMAKER
integer n, W, icount
real(2) Sig_tr, Sig_a, Lambda_tr, D, dx, S_o
real(2), allocatable :: A,, B), Y,, Z)

write(*,*) 'Input the number of nodes '
read(*,*) n
write(*,*) 'Input the length of the slab(W)'
read(*,*) W

Sig_tr = 0.0362;
Sig_a = 0.1532;
S_o = 10e8;
Lambda_tr = 1/Sig_tr ;
D = Lambda_tr/3;
dx = W / (n-1);


allocate(A(n-1,n-1))
allocate(B(n-1))
allocate(Z(n-1))
allocate(Y(n,n))
Y = 0
Z = 0
Y(1,1) = ((D/dx)+(Sig_a*dx/2));
Y(1,2) = -D/dx;
Z(1) = S_o/2;

do icount = 2,n-1
Y(icount,icount) = (2*D)/dx+Sig_a*dx;
Y(icount,icount+1) = -D/dx;
Y(icount,icount-1) = -D/dx;
Z(icount) = 0;
enddo

call FINDInv(matrix, inverse, n, errorflag)


END PROGRAM MATRIXMAKER


SUBROUTINE FINDInv(matrix, inverse, n, errorflag)
IMPLICIT NONE
!Declarations

INTEGER, INTENT(IN) :: n
INTEGER, INTENT(OUT) :: errorflag !Return error status. -1 for error, 0 for normal
REAL, INTENT(IN), DIMENSION(n,n) :: matrix !Input matrix
REAL, INTENT(OUT), DIMENSION(n,n) :: inverse !Inverted matrix

LOGICAL :: FLAG = .TRUE.
INTEGER :: i, j, k
REAL :: m
REAL, DIMENSION(n,2*n) :: augmatrix !augmented matrix


!Augment input matrix with an identity matrix
DO i = 1, n
DO j = 1, 2*n
IF (j <= n ) THEN
augmatrix(i,j) = matrix(i,j)
ELSE IF ((i+n) == j) THEN
augmatrix(i,j) = 1
Else
augmatrix(i,j) = 0
ENDIF
END DO
END DO

!Reduce augmented matrix to upper traingular form
DO k =1, n-1
IF (augmatrix(k,k) == 0) THEN
FLAG = .FALSE.
DO i = k+1, n
IF (augmatrix(i,k) /= 0) THEN
DO j = 1,2*n
augmatrix(k,j) = augmatrix(k,j)+augmatrix(i,j)
END DO
FLAG = .TRUE.
EXIT
ENDIF
IF (FLAG .EQV. .FALSE.) THEN
PRINT*, "Matrix is non - invertible"
inverse = 0
errorflag = -1
return

ENDIF
END DO
ENDIF
DO j = k+1, n
m = augmatrix(j,k)/augmatrix(k,k)
DO i = k, 2*n
augmatrix(j,i) = augmatrix(j,i) - m*augmatrix(k,i)
END DO
END DO
END DO

!Test for invertibility
DO i = 1, n
IF (augmatrix(i,i) == 0) THEN
PRINT*, "Matrix is non - invertible"
inverse = 0
errorflag = -1
return
ENDIF
END DO


!Make diagonal elements as 1
DO i = 1 , n
m = augmatrix(i,i)
DO j = i , (2 * n)
augmatrix(i,j) = (augmatrix(i,j) / m)
END DO
END DO

!Reduced right side half of augmented matrix to identity matrix
DO k = n-1, 1, -1
DO i =1, k
m = augmatrix(i,k+1)
DO j = k, (2*n)
augmatrix(i,j) = augmatrix(i,j) -augmatrix(k+1,j) * m
END DO
END DO
END DO

!store answer
DO i =1, n
DO j = 1, n
inverse(i,j) = augmatrix(i,j+n)
END DO
END DO
errorflag = 0

END SUBROUTINE FINDINV

 

[xwb]

1) Fortran arrays begin at 1: not 0 so your allocates should be allocate(A(n,n)) not n-1

2) Parameter declarations for arrays should be
REAL, INTENT(IN), DIMENSION, :: matrix !Input matrix

Try that first. If it still doesn't work, tell us what the compiler/linker is moaning about.

 

[jecstir2112]

Error 4 SUBROUTINE 'FINDINV' called with argument no 1 as a INTEGER(KIND=3) when a REAL(KIND=1) was expected (from the main program) LINK

 

[xwb]

You need to declare error flag as an integer otherwise it takes it as a real. Also, I think this is what you meant

call findinv (a, y, n, errorflag)