Actual source code: ex1f.F
1: !
2: ! "$Id: ex1f.F,v 1.30 2001/01/17 22:21:32 bsmith Exp $"
3: !
4: ! Program usage: mpirun ex1f [-help] [all PETSc options]
5: !
6: !/*T
7: ! Concepts: vectors^basic routines
8: ! Processors: n
9: !T*/
10: !
11: ! -----------------------------------------------------------------------
13: program main
14: implicit none
16: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
17: ! Include files
18: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
19: !
20: ! The following include statements are required for Fortran programs
21: ! that use PETSc vectors:
22: ! petsc.h - base PETSc routines
23: ! petscvec.h - vectors
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: !
32: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
33: ! Variable declarations
34: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
35: !
36: ! Variables:
37: ! x, y, w - vectors
38: ! z - array of vectors
40: Vec x,y,w,z(5)
41: double precision norm,v,v1,v2
42: integer n,ierr,flg,rank
43: Scalar one,two,three,dots(3),dot
45: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
46: ! Beginning of program
47: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
49: call PetscInitialize(PETSC_NULL_CHARACTER,ierr)
50: one = 1.0
51: two = 2.0
52: three = 3.0
53: n = 20
54: call PetscOptionsGetInt(PETSC_NULL_CHARACTER,'-n',n,flg,ierr)
55: call MPI_Comm_rank(PETSC_COMM_WORLD,rank,ierr)
57: ! Create a vector, specifying only its global dimension.
58: ! When using VecCreate() and VecSetFromOptions(), the vector format (currently parallel
59: ! or sequential) is determined at runtime. Also, the parallel
60: ! partitioning of the vector is determined by PETSc at runtime.
61: !
62: ! Routines for creating particular vector types directly are:
63: ! VecCreateSeq() - uniprocessor vector
64: ! VecCreateMPI() - distributed vector, where the user can
65: ! determine the parallel partitioning
66: ! VecCreateShared() - parallel vector that uses shared memory
67: ! (available only on the SGI); otherwise,
68: ! is the same as VecCreateMPI()
69: !
70: ! VecCreate() and VecSetFromOptions() allows one to determine at runtime which version to use
71: ! with the options -vec_type mpi or -vec_type shared
72: !
73: call VecCreate(PETSC_COMM_WORLD,PETSC_DECIDE,n,x,ierr)
74: call VecSetFromOptions(x,ierr)
76: ! Duplicate some work vectors (of the same format and
77: ! partitioning as the initial vector).
79: call VecDuplicate(x,y,ierr)
80: call VecDuplicate(x,w,ierr)
82: ! Duplicate more work vectors (of the same format and
83: ! partitioning as the initial vector). Here we duplicate
84: ! an array of vectors, which is often more convenient than
85: ! duplicating individual ones.
87: call VecDuplicateVecs(x,3,z,ierr)
89: ! Set the vectors to entries to a constant value.
91: call VecSet(one,x,ierr)
92: call VecSet(two,y,ierr)
93: call VecSet(one,z(1),ierr)
94: call VecSet(two,z(2),ierr)
95: call VecSet(three,z(3),ierr)
97: ! Demonstrate various basic vector routines.
99: call VecDot(x,x,dot,ierr)
100: call VecMDot(3,x,z,dots,ierr)
102: ! Note: If using a complex numbers version of PETSc, then
103: ! PETSC_USE_COMPLEX is defined in the makefiles; otherwise,
104: ! (when using real numbers) it is undefined.
106: if (rank .eq. 0) then
107: #if defined(PETSC_USE_COMPLEX)
108: write(6,100) int(PetscRealPart(dot))
109: write(6,110) int(PetscRealPart(dots(1))), &
110: & int(PetscRealPart(dots(2))), &
111: & int(PetscRealPart(dots(3)))
112: #else
113: write(6,100) int(dot)
114: write(6,110) int(dots(1)),int(dots(2)),int(dots(3))
115: #endif
116: write(6,120)
117: endif
118: 100 format ("Vector length ",i6)
119: 110 format ("Vector length ",3(i6))
120: 120 format ("All other values should be near zero")
122: call VecScale(two,x,ierr)
123: call VecNorm(x,NORM_2,norm,ierr)
124: v = norm-2.0*sqrt(dble(n))
125: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
126: if (rank .eq. 0) write(6,130) v
127: 130 format ("VecScale ",1pe8.2)
129: call VecCopy(x,w,ierr)
130: call VecNorm(w,NORM_2,norm,ierr)
131: v = norm-2.0*sqrt(dble(n))
132: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
133: if (rank .eq. 0) write(6,140) v
134: 140 format ("VecCopy ",1pe8.2)
136: call VecAXPY(three,x,y,ierr)
137: call VecNorm(y,NORM_2,norm,ierr)
138: v = norm-8.0*sqrt(dble(n))
139: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
140: if (rank .eq. 0) write(6,150) v
141: 150 format ("VecAXPY ",1pe8.2)
143: call VecAYPX(two,x,y,ierr)
144: call VecNorm(y,NORM_2,norm,ierr)
145: v = norm-18.0*sqrt(dble(n))
146: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
147: if (rank .eq. 0) write(6,160) v
148: 160 format ("VecAYXP ",1pe8.2)
150: call VecSwap(x,y,ierr)
151: call VecNorm(y,NORM_2,norm,ierr)
152: v = norm-2.0*sqrt(dble(n))
153: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
154: if (rank .eq. 0) write(6,170) v
155: 170 format ("VecSwap ",1pe8.2)
157: call VecNorm(x,NORM_2,norm,ierr)
158: v = norm-18.0*sqrt(dble(n))
159: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
160: if (rank .eq. 0) write(6,180) v
161: 180 format ("VecSwap ",1pe8.2)
163: call VecWAXPY(two,x,y,w,ierr)
164: call VecNorm(w,NORM_2,norm,ierr)
165: v = norm-38.0*sqrt(dble(n))
166: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
167: if (rank .eq. 0) write(6,190) v
168: 190 format ("VecWAXPY ",1pe8.2)
170: call VecPointwiseMult(y,x,w,ierr)
171: call VecNorm(w,NORM_2,norm,ierr)
172: v = norm-36.0*sqrt(dble(n))
173: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
174: if (rank .eq. 0) write(6,200) v
175: 200 format ("VecPointwiseMult ",1pe8.2)
177: call VecPointwiseDivide(x,y,w,ierr)
178: call VecNorm(w,NORM_2,norm,ierr)
179: v = norm-9.0*sqrt(dble(n))
180: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
181: if (rank .eq. 0) write(6,210) v
182: 210 format ("VecPointwiseDivide ",1pe8.2)
184:
185: dots(1) = one
186: dots(2) = three
187: dots(3) = two
188: call VecSet(one,x,ierr)
189: call VecMAXPY(3,dots,x,z,ierr)
190: call VecNorm(z(1),NORM_2,norm,ierr)
191: v = norm-sqrt(dble(n))
192: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
193: call VecNorm(z(2),NORM_2,norm,ierr)
194: v1 = norm-2.0*sqrt(dble(n))
195: if (v1 .gt. -1.d-10 .and. v1 .lt. 1.d-10) v1 = 0.0
196: call VecNorm(z(3),NORM_2,norm,ierr)
197: v2 = norm-3.0*sqrt(dble(n))
198: if (v2 .gt. -1.d-10 .and. v2 .lt. 1.d-10) v2 = 0.0
199: if (rank .eq. 0) write(6,220) v,v1,v2
200: 220 format ("VecMAXPY ",3(1pe8.2))
203: ! Test whether vector has been corrupted (just to demonstrate this
204: ! routine) not needed in most application codes.
206: call VecValid(x,flg,ierr)
207: if (flg .ne. PETSC_TRUE) then
208: if (rank .eq. 0) then
209: write(6,*) 'Corrupted vector!'
210: endif
211: SETERRQ(1,' ',ierr)
212: endif
214: ! Free work space. All PETSc objects should be destroyed when they
215: ! are no longer needed.
217: call VecDestroy(x,ierr)
218: call VecDestroy(y,ierr)
219: call VecDestroy(w,ierr)
220: call VecDestroyVecs(z,3,ierr)
221: call PetscFinalize(ierr)
223: end
224: