Actual source code: ex1f.F
petsc-3.3-p7 2013-05-11
1: !
2: ! Program usage: mpiexec ex1f [-help] [all PETSc options]
3: !
4: !/*T
5: ! Concepts: vectors^basic 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: ! petscsys.h - base PETSc routines
21: ! petscvec.h - vectors
22: ! Additional include statements may be needed if using additional
23: ! PETSc routines in a Fortran program, e.g.,
24: ! petscviewer.h - viewers
25: ! petscis.h - index sets
26: !
27: #include <finclude/petscsys.h>
28: #include <finclude/petscvec.h>
30: !
31: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
32: ! Variable declarations
33: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
34: !
35: ! Variables:
36: ! x, y, w - vectors
37: ! z - array of vectors
39: Vec x,y,w,z(5)
40: PetscReal norm,v,v1,v2
41: PetscInt n,ithree
42: PetscBool flg
43: PetscErrorCode ierr
44: PetscMPIInt rank
45: PetscScalar one,two,three
46: PetscScalar dots(3),dot
47: character*(40) name
49: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
50: ! Beginning of program
51: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
53: call PetscInitialize(PETSC_NULL_CHARACTER,ierr)
54: one = 1.0
55: two = 2.0
56: three = 3.0
57: n = 20
58: ithree = 3
59: call PetscOptionsGetInt(PETSC_NULL_CHARACTER,'-n',n,flg,ierr)
60: call MPI_Comm_rank(PETSC_COMM_WORLD,rank,ierr)
62: ! Create a vector, specifying only its global dimension.
63: ! When using VecCreate(), VecSetSizes() and VecSetFromOptions(),
64: ! the vector format (currently parallel
65: ! or sequential) is determined at runtime. Also, the parallel
66: ! partitioning of the vector is determined by PETSc at runtime.
67: !
68: ! Routines for creating particular vector types directly are:
69: ! VecCreateSeq() - uniprocessor vector
70: ! VecCreateMPI() - distributed vector, where the user can
71: ! determine the parallel partitioning
72: ! VecCreateShared() - parallel vector that uses shared memory
73: ! (available only on the SGI); otherwise,
74: ! is the same as VecCreateMPI()
75: !
76: ! VecCreate(), VecSetSizes() and VecSetFromOptions() allows one
77: ! to determine at runtime which version to use
78: ! with the options -vec_type mpi or -vec_type shared
79: !
80: call VecCreate(PETSC_COMM_WORLD,x,ierr)
81: call VecSetSizes(x,PETSC_DECIDE,n,ierr)
82: call VecSetFromOptions(x,ierr)
83: call VecGetType(x,name,ierr)
85: ! Duplicate some work vectors (of the same format and
86: ! partitioning as the initial vector).
88: call VecDuplicate(x,y,ierr)
89: call VecDuplicate(x,w,ierr)
91: ! Duplicate more work vectors (of the same format and
92: ! partitioning as the initial vector). Here we duplicate
93: ! an array of vectors, which is often more convenient than
94: ! duplicating individual ones.
96: call VecDuplicateVecs(x,ithree,z,ierr)
98: ! Set the vectors to entries to a constant value.
100: call VecSet(x,one,ierr)
102: call VecSet(y,two,ierr)
103: call VecSet(z(1),one,ierr)
104: call VecSet(z(2),two,ierr)
105: call VecSet(z(3),three,ierr)
107: ! Demonstrate various basic vector routines.
109: call VecDot(x,x,dot,ierr)
110: call VecMDot(x,ithree,z,dots,ierr)
112: ! Note: If using a complex numbers version of PETSc, then
113: ! PETSC_USE_COMPLEX is defined in the makefiles; otherwise,
114: ! (when using real numbers) it is undefined.
116: if (rank .eq. 0) then
117: #if defined(PETSC_USE_COMPLEX)
118: write(6,100) int(PetscRealPart(dot))
119: write(6,110) int(PetscRealPart(dots(1))), &
120: & int(PetscRealPart(dots(2))), &
121: & int(PetscRealPart(dots(3)))
122: #else
123: write(6,100) int(dot)
124: write(6,110) int(dots(1)),int(dots(2)),int(dots(3))
125: #endif
126: write(6,120)
127: endif
128: 100 format ('Vector length ',i6)
129: 110 format ('Vector length ',3(i6))
130: 120 format ('All other values should be near zero')
132: call VecScale(x,two,ierr)
133: call VecNorm(x,NORM_2,norm,ierr)
134: v = norm-2.0*sqrt(dble(n))
135: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
136: if (rank .eq. 0) write(6,130) v
137: 130 format ('VecScale ',1pe8.2)
139: call VecCopy(x,w,ierr)
140: call VecNorm(w,NORM_2,norm,ierr)
141: v = norm-2.0*sqrt(dble(n))
142: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
143: if (rank .eq. 0) write(6,140) v
144: 140 format ('VecCopy ',1pe8.2)
146: call VecAXPY(y,three,x,ierr)
147: call VecNorm(y,NORM_2,norm,ierr)
148: v = norm-8.0*sqrt(dble(n))
149: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
150: if (rank .eq. 0) write(6,150) v
151: 150 format ('VecAXPY ',1pe8.2)
153: call VecAYPX(y,two,x,ierr)
154: call VecNorm(y,NORM_2,norm,ierr)
155: v = norm-18.0*sqrt(dble(n))
156: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
157: if (rank .eq. 0) write(6,160) v
158: 160 format ('VecAYXP ',1pe8.2)
160: call VecSwap(x,y,ierr)
161: call VecNorm(y,NORM_2,norm,ierr)
162: v = norm-2.0*sqrt(dble(n))
163: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
164: if (rank .eq. 0) write(6,170) v
165: 170 format ('VecSwap ',1pe8.2)
167: call VecNorm(x,NORM_2,norm,ierr)
168: v = norm-18.0*sqrt(dble(n))
169: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
170: if (rank .eq. 0) write(6,180) v
171: 180 format ('VecSwap ',1pe8.2)
173: call VecWAXPY(w,two,x,y,ierr)
174: call VecNorm(w,NORM_2,norm,ierr)
175: v = norm-38.0*sqrt(dble(n))
176: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
177: if (rank .eq. 0) write(6,190) v
178: 190 format ('VecWAXPY ',1pe8.2)
180: call VecPointwiseMult(w,y,x,ierr)
181: call VecNorm(w,NORM_2,norm,ierr)
182: v = norm-36.0*sqrt(dble(n))
183: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
184: if (rank .eq. 0) write(6,200) v
185: 200 format ('VecPointwiseMult ',1pe8.2)
187: call VecPointwiseDivide(w,x,y,ierr)
188: call VecNorm(w,NORM_2,norm,ierr)
189: v = norm-9.0*sqrt(dble(n))
190: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
191: if (rank .eq. 0) write(6,210) v
192: 210 format ('VecPointwiseDivide ',1pe8.2)
194:
195: dots(1) = one
196: dots(2) = three
197: dots(3) = two
198: call VecSet(x,one,ierr)
199: call VecMAXPY(x,ithree,dots,z,ierr)
200: call VecNorm(z(1),NORM_2,norm,ierr)
201: v = norm-sqrt(dble(n))
202: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
203: call VecNorm(z(2),NORM_2,norm,ierr)
204: v1 = norm-2.0*sqrt(dble(n))
205: if (v1 .gt. -PETSC_SMALL .and. v1 .lt. PETSC_SMALL) v1 = 0.0
206: call VecNorm(z(3),NORM_2,norm,ierr)
207: v2 = norm-3.0*sqrt(dble(n))
208: if (v2 .gt. -PETSC_SMALL .and. v2 .lt. PETSC_SMALL) v2 = 0.0
209: if (rank .eq. 0) write(6,220) v,v1,v2
210: 220 format ('VecMAXPY ',3(1pe8.2))
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 VecDestroyVecs(ithree,z,ierr)
219: call PetscFinalize(ierr)
221: end
222: