Actual source code: ex1f.F
petsc-3.7.5 2017-01-01
1: !
2: !
3: !/*T
4: ! Concepts: vectors^basic routines
5: ! Processors: n
6: !T*/
7: !
8: ! -----------------------------------------------------------------------
10: program main
11: implicit none
13: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
14: ! Include files
15: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
16: !
17: ! The following include statements are required for Fortran programs
18: ! that use PETSc vectors:
19: ! petscsys.h - base PETSc routines
20: ! petscvec.h - vectors
21: ! Additional include statements may be needed if using additional
22: ! PETSc routines in a Fortran program, e.g.,
23: ! petscviewer.h - viewers
24: ! petscis.h - index sets
25: !
26: #include <petsc/finclude/petscsys.h>
27: #include <petsc/finclude/petscvec.h>
29: !
30: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
31: ! Variable declarations
32: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
33: !
34: ! Variables:
35: ! x, y, w - vectors
36: ! z - array of vectors
38: Vec x,y,w,z(5)
39: PetscReal norm,v,v1,v2
40: PetscInt n,ithree
41: PetscBool flg
42: PetscErrorCode ierr
43: PetscMPIInt rank
44: PetscScalar one,two,three
45: PetscScalar dots(3),dot
46: character*(40) name
47: PetscReal nfloat
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_OBJECT,PETSC_NULL_CHARACTER, &
60: & '-n',n,flg,ierr)
61: nfloat = n
62: call MPI_Comm_rank(PETSC_COMM_WORLD,rank,ierr)
64: ! Create a vector, specifying only its global dimension.
65: ! When using VecCreate(), VecSetSizes() and VecSetFromOptions(),
66: ! the vector format (currently parallel
67: ! or sequential) is determined at runtime. Also, the parallel
68: ! partitioning of the vector is determined by PETSc at runtime.
69: !
70: ! Routines for creating particular vector types directly are:
71: ! VecCreateSeq() - uniprocessor vector
72: ! VecCreateMPI() - distributed vector, where the user can
73: ! determine the parallel partitioning
74: ! VecCreateShared() - parallel vector that uses shared memory
75: ! (available only on the SGI); otherwise,
76: ! is the same as VecCreateMPI()
77: !
78: ! VecCreate(), VecSetSizes() and VecSetFromOptions() allows one
79: ! to determine at runtime which version to use
80: ! with the options -vec_type mpi or -vec_type shared
81: !
82: call VecCreate(PETSC_COMM_WORLD,x,ierr)
83: call VecSetSizes(x,PETSC_DECIDE,n,ierr)
84: call VecSetFromOptions(x,ierr)
85: call VecGetType(x,name,ierr)
87: ! Duplicate some work vectors (of the same format and
88: ! partitioning as the initial vector).
90: call VecDuplicate(x,y,ierr)
91: call VecDuplicate(x,w,ierr)
93: ! Duplicate more work vectors (of the same format and
94: ! partitioning as the initial vector). Here we duplicate
95: ! an array of vectors, which is often more convenient than
96: ! duplicating individual ones.
98: call VecDuplicateVecs(x,ithree,z,ierr)
100: ! Set the vectors to entries to a constant value.
102: call VecSet(x,one,ierr)
104: call VecSet(y,two,ierr)
105: call VecSet(z(1),one,ierr)
106: call VecSet(z(2),two,ierr)
107: call VecSet(z(3),three,ierr)
109: ! Demonstrate various basic vector routines.
111: call VecDot(x,x,dot,ierr)
112: call VecMDot(x,ithree,z,dots,ierr)
114: ! Note: If using a complex numbers version of PETSc, then
115: ! PETSC_USE_COMPLEX is defined in the makefiles; otherwise,
116: ! (when using real numbers) it is undefined.
118: if (rank .eq. 0) then
119: #if defined(PETSC_USE_COMPLEX)
120: write(6,100) int(PetscRealPart(dot))
121: write(6,110) int(PetscRealPart(dots(1))), &
122: & int(PetscRealPart(dots(2))), &
123: & int(PetscRealPart(dots(3)))
124: #else
125: write(6,100) int(dot)
126: write(6,110) int(dots(1)),int(dots(2)),int(dots(3))
127: #endif
128: write(6,120)
129: endif
130: 100 format ('Vector length ',i6)
131: 110 format ('Vector length ',3(i6))
132: 120 format ('All other values should be near zero')
134: call VecScale(x,two,ierr)
135: call VecNorm(x,NORM_2,norm,ierr)
136: v = abs(norm-2.0*sqrt(nfloat))
137: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
138: if (rank .eq. 0) write(6,130) v
139: 130 format ('VecScale ',1pe8.2)
141: call VecCopy(x,w,ierr)
142: call VecNorm(w,NORM_2,norm,ierr)
143: v = abs(norm-2.0*sqrt(nfloat))
144: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
145: if (rank .eq. 0) write(6,140) v
146: 140 format ('VecCopy ',1pe8.2)
148: call VecAXPY(y,three,x,ierr)
149: call VecNorm(y,NORM_2,norm,ierr)
150: v = abs(norm-8.0*sqrt(nfloat))
151: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
152: if (rank .eq. 0) write(6,150) v
153: 150 format ('VecAXPY ',1pe8.2)
155: call VecAYPX(y,two,x,ierr)
156: call VecNorm(y,NORM_2,norm,ierr)
157: v = abs(norm-18.0*sqrt(nfloat))
158: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
159: if (rank .eq. 0) write(6,160) v
160: 160 format ('VecAYXP ',1pe8.2)
162: call VecSwap(x,y,ierr)
163: call VecNorm(y,NORM_2,norm,ierr)
164: v = abs(norm-2.0*sqrt(nfloat))
165: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
166: if (rank .eq. 0) write(6,170) v
167: 170 format ('VecSwap ',1pe8.2)
169: call VecNorm(x,NORM_2,norm,ierr)
170: v = abs(norm-18.0*sqrt(nfloat))
171: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
172: if (rank .eq. 0) write(6,180) v
173: 180 format ('VecSwap ',1pe8.2)
175: call VecWAXPY(w,two,x,y,ierr)
176: call VecNorm(w,NORM_2,norm,ierr)
177: v = abs(norm-38.0*sqrt(nfloat))
178: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
179: if (rank .eq. 0) write(6,190) v
180: 190 format ('VecWAXPY ',1pe8.2)
182: call VecPointwiseMult(w,y,x,ierr)
183: call VecNorm(w,NORM_2,norm,ierr)
184: v = abs(norm-36.0*sqrt(nfloat))
185: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
186: if (rank .eq. 0) write(6,200) v
187: 200 format ('VecPointwiseMult ',1pe8.2)
189: call VecPointwiseDivide(w,x,y,ierr)
190: call VecNorm(w,NORM_2,norm,ierr)
191: v = abs(norm-9.0*sqrt(nfloat))
192: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
193: if (rank .eq. 0) write(6,210) v
194: 210 format ('VecPointwiseDivide ',1pe8.2)
197: dots(1) = one
198: dots(2) = three
199: dots(3) = two
200: call VecSet(x,one,ierr)
201: call VecMAXPY(x,ithree,dots,z,ierr)
202: call VecNorm(z(1),NORM_2,norm,ierr)
203: v = abs(norm-sqrt(nfloat))
204: if (v .gt. -PETSC_SMALL .and. v .lt. PETSC_SMALL) v = 0.0
205: call VecNorm(z(2),NORM_2,norm,ierr)
206: v1 = abs(norm-2.0*sqrt(nfloat))
207: if (v1 .gt. -PETSC_SMALL .and. v1 .lt. PETSC_SMALL) v1 = 0.0
208: call VecNorm(z(3),NORM_2,norm,ierr)
209: v2 = abs(norm-3.0*sqrt(nfloat))
210: if (v2 .gt. -PETSC_SMALL .and. v2 .lt. PETSC_SMALL) v2 = 0.0
211: if (rank .eq. 0) write(6,220) v,v1,v2
212: 220 format ('VecMAXPY ',3(2x,1pe8.2))
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(ithree,z,ierr)
221: call PetscFinalize(ierr)
223: end