d1r4.f90

Visual Fortran常用数值算法集

program D1R4
!Driver program for routine PENDAG
PARAMETER(N=7)
DIMENSION A1(N,N),A(N),B(N),C(N),D(N),E(N),&
          R(N),U(N),X(N)
DATA A1/4.,1.,1.,0.,0.,0.,0.,1.,5.,2.,2.,0.,0.,0.,&
        1.,2.,6.,3.,3.,0.,0.,0.,2.,3.,7.,4.,4.,0.,&
		0.,0.,3.,4.,8.,5.,5.,0.,0.,0.,4.,5.,9.,6.,&
		0.,0.,0.,0.,5.,6.,10./
DATA R/1.,2.,3.,4.,5.,6.,7./
Print*,'已知的方程组的右端向量'
DO I=1,N
    WRITE(*,'(1X,3F12.6)') R(I)
END DO
DO I=3,N
    A(I)=A1(I,I-2)
END DO 
DO I=2,N
    B(I)=A1(I,I-1)
END DO
DO I=1,N-1
    D(I)=A1(I,I+1)
END DO
DO I=1,N-2
    E(I)=A1(I,I+2)
END DO
DO I=1,N
    C(I)=A1(I,I)
END DO
Call PENDAG(A,B,C,D,E,R,U,N)
WRITE(*,*)
Print*, '计算出的方程组的解'
DO I=1,N
    WRITE(*,'(1X,3F12.6)') U(I)
END DO
!将计算出的解B乘以系数矩阵，以验证计算结果正确
DO L=1,N
    x(L)=0.
    DO J=1,N
        X(L)=X(L)+A1(L,J)*U(J)
    END DO 
END DO 
WRITE(*,*)
Print*,'计算出的解乘以系数矩阵的结果'
DO I=1,N
    WRITE(*,'(1X,3F12.6)') X(I)
END DO
END