INTERPOLATION DEMONSTRATION

!Print out final data
WRITE(*,*) ’Lower Airfoil Data’
WRITE(*,*) ’  X-Values    Linear Cp    Newton-Raphson Cp’
DO i = 1,SIZE(lower,1),1
	WRITE(*,*) lower(i, 1:3)
ENDDO
WRITE(*,*) ’Upper Airfoil Data’
WRITE(*,*) ’  X-Values    Linear Cp    Newton-Raphson Cp’
DO i = 1,SIZE(upper,1),1
	WRITE(*,*) upper(i, 1:3)
ENDDO
​
!Deallocate x and Cp arrays
IF (ALLOCATED(x)) THEN
	DEALLOCATE(x, STAT=ierr1)
ENDIF
IF (ALLOCATED(Cp)) THEN
	DEALLOCATE(Cp, STAT=ierr2)
ENDIF
IF ((ierr1 .EQ. 0) .AND. (ierr2 .EQ. 0)) THEN
	WRITE(*,*) ’Memory successfully deallocated.’
ELSE
	WRITE(*,*) ’Memory not successfully deallocated.’
ENDIF
​
​
CONTAINS
!———————————————————————--
SUBROUTINE readFile
	IMPLICIT NONE
	INTEGER :: i, ios, nl
	!REAL :: z
​
	WRITE(*,*) ’Reading from file: ’, myfile
	!Open file to read from it
	OPEN(UNIT=1, FILE=myfile)
​
	!Determine the number of lines in the file
	nl = 0 !Initialize
	DO i = 1,1000,1
		READ (1, *, IOSTAT=ios) !Dummy variable
		!If it’s the end of the file, then exit
		IF (ios /= 0) THEN
			EXIT
		ELSEIF (i == 1000) THEN
			WRITE (*,*) ’Maximum allowable data input reached. (1000 lines)’
		ELSE
			nl = nl + 1
		ENDIF
	ENDDO
	WRITE(*,*) ’End of file found:’, nl, ’pieces of data total.’
	WRITE(*,*) ’’
	CLOSE(1)
​
	!Use this number to allocate size to x and Cp
	ALLOCATE(x(nl), STAT=ierr1)
	ALLOCATE(Cp(nl), STAT=ierr2)
	IF ((ierr1 .NE. 0) .OR. (ierr2 .NE. 0)) THEN
		WRITE(*,*) ’Allocation denied.  Program terminated.’
		STOP
	ENDIF
​
	OPEN(UNIT=1, FILE=myfile)
	!Read from file
	DO i=1,nl,1
		READ(1, *, IOSTAT=ios) x(i), Cp(i)
	END DO
​
	CLOSE(1)
END SUBROUTINE readFile
!———————————————————————--
​
​
!———————————————————————--
SUBROUTINE linearForm(arr, row, str)
	IMPLICIT NONE
	REAL, DIMENSION(2,2) :: arr
	INTEGER :: row
	CHARACTER(5) :: str
	
	!Use linear 1st order Taylor series
	!f(x) = f(x_0) + [(x - x_0)/(x_1 - x_0)] * [f(x_1) - f(x_0)]
	IF (str == ’lower’) THEN
		lower(row, 2) = arr(1,2) + ((lower(row,1) - arr(1,1)) / (arr(2,1) - arr(1,1))) * (arr(2,2) - arr(1,2))
	ELSEIF (str == ’upper’) THEN
		upper(row, 2) = arr(1,2) + ((upper(row,1) - arr(1,1)) / (arr(2,1) - arr(1,1))) * (arr(2,2) - arr(1,2))
	ENDIF
	
END SUBROUTINE linearForm