Actual source code: ex1f.F90
petsc-3.9.4 2018-09-11
1: !
2: !
3: !/*T
4: ! Concepts: vectors^basic routines
5: ! Processors: n
6: !T*/
7: !
8: ! -----------------------------------------------------------------------
10: program main
11: #include <petsc/finclude/petscvec.h>
12: use petscvec
13: implicit none
15: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
16: ! Variable declarations
17: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
18: !
19: ! Variables:
20: ! x, y, w - vectors
21: ! z - array of vectors
23: Vec x,y,w,z(5)
24: PetscReal norm,v,v1,v2
25: PetscInt n,ithree
26: PetscBool flg
27: PetscErrorCode ierr
28: PetscMPIInt rank
29: PetscScalar one,two,three
30: PetscScalar dots(3),dot
31: character*(40) name
32: PetscReal nfloat
34: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
35: ! Beginning of program
36: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
38: call PetscInitialize(PETSC_NULL_CHARACTER,ierr)
39: if (ierr .ne. 0) then
40: print*,'Unable to initialize PETSc'
41: stop
42: endif
43: one = 1.0
44: two = 2.0
45: three = 3.0
46: n = 20
47: ithree = 3
48: call PetscOptionsGetInt(PETSC_NULL_OPTIONS,PETSC_NULL_CHARACTER,'-n',n,flg,ierr)
49: nfloat = n
50: call MPI_Comm_rank(PETSC_COMM_WORLD,rank,ierr)
52: ! Create a vector, specifying only its global dimension.
53: ! When using VecCreate(), VecSetSizes() and VecSetFromOptions(),
54: ! the vector format (currently parallel
55: ! or sequential) is determined at runtime. Also, the parallel
56: ! partitioning of the vector is determined by PETSc at runtime.
57: !
58: ! Routines for creating particular vector types directly are:
59: ! VecCreateSeq() - uniprocessor vector
60: ! VecCreateMPI() - distributed vector, where the user can
61: ! determine the parallel partitioning
62: ! VecCreateShared() - parallel vector that uses shared memory
63: ! (available only on the SGI); otherwise,
64: ! is the same as VecCreateMPI()
65: !
66: ! VecCreate(), VecSetSizes() and VecSetFromOptions() allows one
67: ! to determine at runtime which version to use
68: ! with the options -vec_type mpi or -vec_type shared
69: !
70: call VecCreate(PETSC_COMM_WORLD,x,ierr)
71: call VecSetSizes(x,PETSC_DECIDE,n,ierr)
72: call VecSetFromOptions(x,ierr)
73: call VecGetType(x,name,ierr)
75: ! Duplicate some work vectors (of the same format and
76: ! partitioning as the initial vector).
78: call VecDuplicate(x,y,ierr)
79: call VecDuplicate(x,w,ierr)
81: ! Duplicate more work vectors (of the same format and
82: ! partitioning as the initial vector). Here we duplicate
83: ! an array of vectors, which is often more convenient than
84: ! duplicating individual ones.
86: call VecDuplicateVecs(x,ithree,z,ierr)
88: ! Set the vectors to entries to a constant value.
90: call VecSet(x,one,ierr)
92: call VecSet(y,two,ierr)
93: call VecSet(z(1),one,ierr)
94: call VecSet(z(2),two,ierr)
95: call VecSet(z(3),three,ierr)
97: ! Demonstrate various basic vector routines.
99: call VecDot(x,x,dot,ierr)
100: call VecMDot(x,ithree,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))),int(PetscRealPart(dots(2))),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 = abs(norm-2.0*sqrt(nfloat))
123: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
124: if (rank .eq. 0) write(6,130) v
125: 130 format ('VecScale ',1pe9.2)
127: call VecCopy(x,w,ierr)
128: call VecNorm(w,NORM_2,norm,ierr)
129: v = abs(norm-2.0*sqrt(nfloat))
130: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
131: if (rank .eq. 0) write(6,140) v
132: 140 format ('VecCopy ',1pe9.2)
134: call VecAXPY(y,three,x,ierr)
135: call VecNorm(y,NORM_2,norm,ierr)
136: v = abs(norm-8.0*sqrt(nfloat))
137: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
138: if (rank .eq. 0) write(6,150) v
139: 150 format ('VecAXPY ',1pe9.2)
141: call VecAYPX(y,two,x,ierr)
142: call VecNorm(y,NORM_2,norm,ierr)
143: v = abs(norm-18.0*sqrt(nfloat))
144: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
145: if (rank .eq. 0) write(6,160) v
146: 160 format ('VecAYXP ',1pe9.2)
148: call VecSwap(x,y,ierr)
149: call VecNorm(y,NORM_2,norm,ierr)
150: v = abs(norm-2.0*sqrt(nfloat))
151: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
152: if (rank .eq. 0) write(6,170) v
153: 170 format ('VecSwap ',1pe9.2)
155: call VecNorm(x,NORM_2,norm,ierr)
156: v = abs(norm-18.0*sqrt(nfloat))
157: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
158: if (rank .eq. 0) write(6,180) v
159: 180 format ('VecSwap ',1pe9.2)
161: call VecWAXPY(w,two,x,y,ierr)
162: call VecNorm(w,NORM_2,norm,ierr)
163: v = abs(norm-38.0*sqrt(nfloat))
164: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
165: if (rank .eq. 0) write(6,190) v
166: 190 format ('VecWAXPY ',1pe9.2)
168: call VecPointwiseMult(w,y,x,ierr)
169: call VecNorm(w,NORM_2,norm,ierr)
170: v = abs(norm-36.0*sqrt(nfloat))
171: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
172: if (rank .eq. 0) write(6,200) v
173: 200 format ('VecPointwiseMult ',1pe9.2)
175: call VecPointwiseDivide(w,x,y,ierr)
176: call VecNorm(w,NORM_2,norm,ierr)
177: v = abs(norm-9.0*sqrt(nfloat))
178: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
179: if (rank .eq. 0) write(6,210) v
180: 210 format ('VecPointwiseDivide ',1pe9.2)
183: dots(1) = one
184: dots(2) = three
185: dots(3) = two
186: call VecSet(x,one,ierr)
187: call VecMAXPY(x,ithree,dots,z,ierr)
188: call VecNorm(z(1),NORM_2,norm,ierr)
189: v = abs(norm-sqrt(nfloat))
190: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
191: call VecNorm(z(2),NORM_2,norm,ierr)
192: v1 = abs(norm-2.0*sqrt(nfloat))
193: if (v1 .gt. -PETSC_SMALL .and. v1 .lt. PETSC_SMALL) v1 = 0.0
194: call VecNorm(z(3),NORM_2,norm,ierr)
195: v2 = abs(norm-3.0*sqrt(nfloat))
196: if (v2 .gt. -PETSC_SMALL .and. v2 .lt. PETSC_SMALL) v2 = 0.0
197: if (rank .eq. 0) write(6,220) v,v1,v2
198: 220 format ('VecMAXPY ',3(2x,1pe9.2))
200: ! Free work space. All PETSc objects should be destroyed when they
201: ! are no longer needed.
203: call VecDestroy(x,ierr)
204: call VecDestroy(y,ierr)
205: call VecDestroy(w,ierr)
206: call VecDestroyVecs(ithree,z,ierr)
207: call PetscFinalize(ierr)
209: end
211: !
212: !/*TEST
213: !
214: ! test:
215: ! suffix: 1
216: !
217: ! test:
218: ! suffix: 2
219: ! nsize: 2
220: !
221: !TEST*/