Every time I compile this program I get these errors...
- (This error occurs every time I try to call the subroutine.)
103 | call ColumnInsert(M(n,n), b, n, col, MatOut(n,n))
| 1
Error: Explicit interface required for ‘columninsert’ at (1): assumed-shape argument
- (This error also occurs every time I run the function)
107 | detA = Determinant (MatOut(:,:), n)
| 1
Error: Type mismatch in argument ‘m’ at (1); passed INTEGER(4) to REAL(8)
Here is the main program:
program CramersRule
! System of equations. 2x2, 3x3
implicit none
! Declare varialble
integer :: n, row, col, i
real*8, allocatable :: Matrix1(:,:), b(:), x(:)
real*8 :: detA, detM, determinant
logical :: Success
! Open the input and output files.
open(42,file='Data2.txt')
open(43,file='Data2Out.txt')
! Solve each system in the input files.
do
! Read in size of first system.
read(42,*) n
if (n .eq. 0) exit ! Quit if zero.
! Allocate memory for system, right hand side, and solution vector.
allocate(Matrix1(n,n), b(n), x(n))
! Read in the system. Ask if you do not understand how this works!
do row = 1, n
read(42,*) (Matrix1(row, col), col = 1, n), b(row)
print*, Matrix1
enddo
! Use cramers rule to get solution.
call Cramer(Matrix1, b, n, x, Success)
if (Success) then
! Write solution to file
do row = 1, n
write(43,*) x(row)
enddo
write(43,*)
else ! This happens when there is no unique solution.
write(43,*) 'No Solution'
write(43,*)
endif
! clean up memory and go back up to top for next system.
deallocate(Matrix1, b, x)
enddo
! close files
close(42)
close(43)
end program CramersRule
subroutine Cramer(M, b, n, x, Success)
! This subroutine does Cramer's Rule
implicit none
! Declare and initialize your variables first.
real*8, allocatable :: M(:,:), b(:), x(:)
integer :: n, row, col, i
integer :: MatOut(n,n)
real*8 :: detA, detM, x1, x2, x3, Determinant, solution1, solution2, solution3
logical :: Success
! Find the determinant of M first. print it to screen.
detM = Determinant(M, n)
print*, "The determinant of this matrix is = ", detM
! If it is zero, set the Success logical variable and quit.
if (detM .eq. 0) then
Success = .false.
return
end if
! Allocate memory for a working matrix for column substituion. Then, for each
! column, i, substitute column i with vector b and get that determinant.
! Compute the ith solution.
if (n .eq. 2)then
col = 1
call ColumnInsert(M(n,n), b, n, col, MatOut(n,n))
print*, MatOut(:,:)
detA = Determinant (MatOut(:,:), n)
x1 = detA/detM
solution1 = x1
col = col + 1
call ColumnInsert(M, b, n, col, MatOut)
print*, MatOut(:,:)
detA = Determinant (MatOut(:,:), n)
x2 = detA/detM
solution2 = x2
success = .true.
return
else
col = 1
call ColumnInsert(M, b, n, col, MatOut)
print*, MatOut(:,:)
detA = Determinant (MatOut(:,:), n)
x1 = detA/detM
solution1 = x1
col = col + 1
call ColumnInsert(M, b, n, col, MatOut)
print*, MatOut(:,:)
detA = Determinant (MatOut(:,:), n)
x2 = detA/detM
solution2 = x2
col = col +1
call ColumnInsert(M, b, n, col, MatOut)
print*, MatOut(:,:)
detA = Determinant (MatOut(:,:), n)
x3 = detA/detM
solution3 = x3
success = .true.
return
end if
! deallocate memory for the working matrix.
deallocate(M, b, x)
end subroutine Cramer
subroutine ColumnInsert(M, b, n, col, MatOut)
! This subroutine takes vector b and inserts in into matrix M at column col.
implicit none
integer :: n
integer, intent(out) :: col, MatOut(:,:)
real :: a, b1, c, d, e, f, g, h, j, k, l, m1
double precision :: M(n,n), b(1,n)
if (n .eq. 2)then
a = M(1,1)
b1 = M(1,2)
c = M(2,1)
d = M(2,2)
e = b(1,1)
f = b(1,2)
!the next if statement substitutes based on which column the main program asks for
if (col .eq. 1)then
M(1,1) = e
M(1,2) = f
M(2,1) = c
M(2,2) = d
MatOut(:,:) = M(:,:)
print*, MatOut(:,:)
return
else
M(1,1) = a
M(1,2) = b1
M(2,1) = e
M(2,2) = f
MatOut(:,:) = M(:,:)
print*, MatOut(:,:)
return
endif
!this is for 3x3 matricies
else
a = M(1,1)
b1 = M(1,2)
c = M(1,3)
d = M(2,1)
e = M(2,2)
f = M(2,3)
g = M(3,1)
h = M(3,2)
j = M(3,3)
k = b(1,1)
l = b(1,2)
m1 = b(1,3)
if (col .eq. 1) then
M(1,1) = k
M(1,2) = l
M(1,3) = m1
M(2,1) = d
M(2,2) = e
M(2,3) = f
M(3,1) = g
M(3,2) = h
M(3,3) = j
MatOut(:,:) = M(:,:)
print*, MatOut(:,:)
return
else if (col .eq. 2)then
M(1,1) = a
M(1,2) = b1
M(1,3) = c
M(2,1) = k
M(2,2) = l
M(2,3) = m1
M(3,1) = g
M(3,2) = h
M(3,3) = j
MatOut(:,:) = M(:,:)
print*, MatOut(:,:)
return
else
M(1,1) = a
M(1,2) = b1
M(1,3) = c
M(2,1) = d
M(2,2) = e
M(2,3) = f
M(3,1) = k
M(3,2) = l
M(3,3) = m1
MatOut(:,:) = M(:,:)
print*, MatOut(:,:)
return
endif
endif
end subroutine ColumnInsert
function Determinant(M, n) result(Det)
!pulled straight from lab 2 in week 4
integer :: n
real*8 :: M(n,n), Det, a, b, c, d, e, f, g, h, j
if (n .eq. 2) then
a = M(1,1)
b = M(1,2)
c = M(2,1)
d = M(2,2)
Det = (a*d)-(b*c)
else
a = M(1,1)
b = M(1,2)
c = M(1,3)
d = M(2,1)
e = M(2,2)
f = M(2,3)
g = M(3,1)
h = M(3,2)
j = M(3,3)
Det = (a*e*j)+(b*f*g)+(c*d*h)-(c*e*g)-(b*d*j)-(a*f*h)
endif
end function Determinant
I know this might seem like a dumb question to be asking, but I cannot for the life of me find where I need to change something. Any help or guidance is greatly appreciated. Thanks!
