Actual source code: ex1f90.F
1: !
2: !
3: !/*T
4: ! Concepts: vectors^using basic vector routines;
5: ! Concepts: Fortran90^using basic vector routines;
6: ! Processors: n
7: !T*/
8: !
9: ! -----------------------------------------------------------------------
11: program main
12: implicit none
14: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
15: ! Include files
16: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
17: !
18: ! The following include statements are required for Fortran programs
19: ! that use PETSc vectors:
20: ! petsc.h - base PETSc routines
21: ! petscvec.h - vectors
22: ! petscvec.h90 - to allow access to Fortran90 features of vectors
23: !
24: ! Additional include statements may be needed if using additional
25: ! PETSc routines in a Fortran program, e.g.,
26: ! petscviewer.h - viewers
27: ! petscis.h - index sets
28: !
29: #include include/finclude/petsc.h
30: #include include/finclude/petscvec.h
31: #include "include/finclude/petscvec.h90"
32: !
33: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
34: ! Variable declarations
35: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
36: !
37: ! Variables:
38: ! x, y, w - vectors
39: ! z - array of vectors
40: !
41: Vec x,y,w
42: Vec, pointer :: z(:)
43: double precision norm,v,v1,v2
44: integer n,ierr,flg,rank
45: PetscScalar one,two,three,dots(3),dot
47: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
48: ! Beginning of program
49: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
51: call PetscInitialize(PETSC_NULL_CHARACTER,ierr)
52: one = 1.0
53: two = 2.0
54: three = 3.0
55: n = 20
56: call PetscOptionsGetInt(PETSC_NULL_CHARACTER,'-n',n,flg,ierr)
57: call MPI_Comm_rank(PETSC_COMM_WORLD,rank,ierr)
59: ! Create a vector, specifying only its global dimension.
60: ! When using VecCreate(), VecSetSizes() and VecSetFromOptions(),
61: ! the vector format (currently parallel
62: ! or sequential) is determined at runtime. Also, the parallel
63: ! partitioning of the vector is determined by PETSc at runtime.
64: !
65: ! Routines for creating particular vector types directly are:
66: ! VecCreateSeq() - uniprocessor vector
67: ! VecCreateMPI() - distributed vector, where the user can
68: ! determine the parallel partitioning
70: call VecCreate(PETSC_COMM_WORLD,x,ierr)
71: call VecSetSizes(x,PETSC_DECIDE,n,ierr)
72: call VecSetFromOptions(x,ierr)
74: ! Duplicate some work vectors (of the same format and
75: ! partitioning as the initial vector).
77: call VecDuplicate(x,y,ierr)
78: call VecDuplicate(x,w,ierr)
80: ! Duplicate more work vectors (of the same format and
81: ! partitioning as the initial vector). Here we duplicate
82: ! an array of vectors, which is often more convenient than
83: ! duplicating individual ones.
85: call VecDuplicateVecsF90(x,3,z,ierr)
87: ! Set the vectors to entries to a constant value.
89: call VecSet(x,one,ierr)
90: call VecSet(y,two,ierr)
91: call VecSet(z(1),one,ierr)
92: call VecSet(z(2),two,ierr)
93: call VecSet(z(3),three,ierr)
95: ! Demonstrate various basic vector routines.
97: call VecDot(x,x,dot,ierr)
98: call VecMDot(3,x,z,dots,ierr)
100: ! Note: If using a complex numbers version of PETSc, then
101: ! PETSC_USE_COMPLEX is defined in the makefiles; otherwise,
102: ! (when using real numbers) it is undefined.
104: if (rank .eq. 0) then
105: #if defined(PETSC_USE_COMPLEX)
106: write(6,100) int(PetscRealPart(dot))
107: write(6,110) int(PetscRealPart(dots(1))), &
108: & int(PetscRealPart(dots(2))), &
109: & int(PetscRealPart(dots(3)))
110: #else
111: write(6,100) int(dot)
112: write(6,110) int(dots(1)),int(dots(2)),int(dots(3))
113: #endif
114: write(6,120)
115: endif
116: 100 format ("Vector length ",i6)
117: 110 format ("Vector length ",3(i6))
118: 120 format ("All other values should be near zero")
120: call VecScale(x,two,ierr)
121: call VecNorm(x,NORM_2,norm,ierr)
122: v = norm-2.0*sqrt(dble(n))
123: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
124: if (rank .eq. 0) write(6,130) v
125: 130 format ("VecScale ",1pe8.2)
127: call VecCopy(x,w,ierr)
128: call VecNorm(w,NORM_2,norm,ierr)
129: v = norm-2.0*sqrt(dble(n))
130: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
131: if (rank .eq. 0) write(6,140) v
132: 140 format ("VecCopy ",1pe8.2)
134: call VecAXPY(y,three,x,ierr)
135: call VecNorm(y,NORM_2,norm,ierr)
136: v = norm-8.0*sqrt(dble(n))
137: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
138: if (rank .eq. 0) write(6,150) v
139: 150 format ("VecAXPY ",1pe8.2)
141: call VecAYPX(y,two,x,ierr)
142: call VecNorm(y,NORM_2,norm,ierr)
143: v = norm-18.0*sqrt(dble(n))
144: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
145: if (rank .eq. 0) write(6,160) v
146: 160 format ("VecAYXP ",1pe8.2)
148: call VecSwap(x,y,ierr)
149: call VecNorm(y,NORM_2,norm,ierr)
150: v = norm-2.0*sqrt(dble(n))
151: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
152: if (rank .eq. 0) write(6,170) v
153: 170 format ("VecSwap ",1pe8.2)
155: call VecNorm(x,NORM_2,norm,ierr)
156: v = norm-18.0*sqrt(dble(n))
157: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
158: if (rank .eq. 0) write(6,180) v
159: 180 format ("VecSwap ",1pe8.2)
161: call VecWAXPY(w,two,x,y,ierr)
162: call VecNorm(w,NORM_2,norm,ierr)
163: v = norm-38.0*sqrt(dble(n))
164: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
165: if (rank .eq. 0) write(6,190) v
166: 190 format ("VecWAXPY ",1pe8.2)
168: call VecPointwiseMult(w,y,x,ierr)
169: call VecNorm(w,NORM_2,norm,ierr)
170: v = norm-36.0*sqrt(dble(n))
171: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
172: if (rank .eq. 0) write(6,200) v
173: 200 format ("VecPointwiseMult ",1pe8.2)
175: call VecPointwiseDivide(w,x,y,ierr)
176: call VecNorm(w,NORM_2,norm,ierr)
177: v = norm-9.0*sqrt(dble(n))
178: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
179: if (rank .eq. 0) write(6,210) v
180: 210 format ("VecPointwiseDivide ",1pe8.2)
182:
183: dots(1) = one
184: dots(2) = three
185: dots(3) = two
186: call VecSet(x,one,ierr)
187: call VecMAXPY(x,3,dots,z,ierr)
188: call VecNorm(z(1),NORM_2,norm,ierr)
189: v = norm-sqrt(dble(n))
190: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
191: call VecNorm(z(2),NORM_2,norm,ierr)
192: v1 = norm-2.0*sqrt(dble(n))
193: if (v1 .gt. -1.d-10 .and. v1 .lt. 1.d-10) v1 = 0.0
194: call VecNorm(z(3),NORM_2,norm,ierr)
195: v2 = norm-3.0*sqrt(dble(n))
196: if (v2 .gt. -1.d-10 .and. v2 .lt. 1.d-10) v2 = 0.0
197: if (rank .eq. 0) write(6,220) v,v1,v2
198: 220 format ("VecMAXPY ",3(1pe8.2))
201: ! Test whether vector has been corrupted (just to demonstrate this
202: ! routine) not needed in most application codes.
204: call VecValid(x,flg,ierr)
205: if (flg .ne. PETSC_TRUE) then
206: if (rank .eq. 0) then
207: write(6,*) 'Corrupted vector!'
208: endif
209: SETERRQ(1,' ',ierr)
210: endif
212: ! Free work space. All PETSc objects should be destroyed when they
213: ! are no longer needed.
215: call VecDestroy(x,ierr)
216: call VecDestroy(y,ierr)
217: call VecDestroy(w,ierr)
218: call VecDestroyVecsF90(z,3,ierr)
219: call PetscFinalize(ierr)
221: end
222: