(15:19 ian@ian-Aspire-One-753 source) > gfortran cholesky.f -ffree-form -o cholesky (15:20 ian@ian-Aspire-One-753 source) > ./cholesky 5.0 0.0 0.0 3.0 3.0 0.0 -1.0 1.0 3.0 (15:20 ian@ian-Aspire-One-753 source) > cat cholesky.f !=={{header|Fortran}}== !Program Cholesky_decomp ! ! ! LBH @ ULPGC 06/03/2014 ! Compute the Cholesky decomposition for a matrix A ! after the attached ! http://rosettacode.org/wiki/Cholesky_decomposition ! note that the matrix A is complex since there might ! be values, where the sqrt has complex solutions. ! Here, only the real values are taken into account !! implicit none

INTEGER, PARAMETER :: m=3 !rows INTEGER, PARAMETER :: n=3 !cols COMPLEX, DIMENSION(m,n) :: A REAL, DIMENSION(m,n) :: L REAL :: sum1, sum2 INTEGER i,j,k

! Assign values to the matrix A(1,:)=(/ 25, 15, -5 /)
A(2,:)=(/ 15, 18, 0 /)
A(3,:)=(/ -5, 0, 11 /) ! !!!!!!!!!!!another example!!!!!!! ! A(1,:) = (/ 18, 22, 54, 42 /) ! A(2,:) = (/ 22, 70, 86, 62 /) ! A(3,:) = (/ 54, 86, 174, 134 /) ! A(4,:) = (/ 42, 62, 134, 106 /)

! Initialize values L(1,1)=real(sqrt(A(1,1))) L(2,1)=A(2,1)/L(1,1) L(2,2)=real(sqrt(A(2,2)-L(2,1)*L(2,1))) L(3,1)=A(3,1)/L(1,1) ! for greater order than m,n=3 add initial row value ! for instance if m,n=4 then add the following line ! L(4,1)=A(4,1)/L(1,1)

do i=1,n do k=1,i sum1=0 sum2=0 do j=1,k-1 if (i==k) then sum1=sum1+(L(k,j)*L(k,j)) L(k,k)=real(sqrt(A(k,k)-sum1))
elseif (i > k) then sum2=sum2+(L(i,j)L(k,j)) L(i,k)=(1/L(k,k))(A(i,k)-sum2) else L(i,k)=0 end if end do end do end do

! write output do i=1,m print "(3(1X,F6.1))",L(i,:) end do

End program ! !{{out}} !

!   5.0   0.0   0.0
!   3.0   3.0   0.0
!  -1.0   1.0   3.0
!

SLOC Directory SLOC-by-Language (Sorted) 34 top_dir fortran=34

Totals grouped by language (dominant language first): fortran: 34 (100.00%)

Total Physical Source Lines of Code (SLOC) = 34 Development Effort Estimate, Person-Years (Person-Months) = 0.01 (0.07) (Basic COCOMO model, Person-Months = 2.4 * (KSLOC1.05)) Schedule Estimate, Years (Months) = 0.08 (0.90) (Basic COCOMO model, Months = 2.5 * (person-months0.38)) Estimated Average Number of Developers (Effort/Schedule) = 0.08 Total Estimated Cost to Develop = $ 776 (average salary = $56,286/year, overhead = 2.40). SLOCCount, Copyright (C) 2001-2004 David A. Wheeler SLOCCount is Open Source Software/Free Software, licensed under the GNU GPL. SLOCCount comes with ABSOLUTELY NO WARRANTY, and you are welcome to redistribute it under certain conditions as specified by the GNU GPL license; see the documentation for details. Please credit this data as "generated using David A. Wheeler's 'SLOCCount'." (15:21 ian@ian-Aspire-One-753 source) >