Actual source code: ex1f90.F90
petsc-3.8.4 2018-03-24
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: #include <petsc/finclude/petscvec.h>
13: use petscvec
14: implicit none
16: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
17: ! Variable declarations
18: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
19: !
20: ! Variables:
21: ! x, y, w - vectors
22: ! z - array of vectors
23: !
24: Vec x,y,w
25: Vec, pointer :: z(:)
26: PetscReal norm,v,v1,v2
27: PetscInt n,ithree
28: PetscErrorCode ierr
29: PetscMPIInt rank
30: PetscBool flg
31: PetscScalar one,two,three
32: PetscScalar dots(3),dot
33: PetscReal nfloat
35: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
36: ! Beginning of program
37: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
39: call PetscInitialize(PETSC_NULL_CHARACTER,ierr)
40: if (ierr .ne. 0) then
41: print*,'Unable to initialize PETSc'
42: stop
43: endif
44: one = 1.0
45: two = 2.0
46: three = 3.0
47: n = 20
48: ithree = 3
50: call PetscOptionsGetInt(PETSC_NULL_OPTIONS,PETSC_NULL_CHARACTER,'-n',n,flg,ierr);CHKERRA(ierr)
51: nfloat = n
52: call MPI_Comm_rank(PETSC_COMM_WORLD,rank,ierr);CHKERRA(ierr)
54: ! Create a vector, specifying only its global dimension.
55: ! When using VecCreate(), VecSetSizes() and VecSetFromOptions(),
56: ! the vector format (currently parallel
57: ! or sequential) is determined at runtime. Also, the parallel
58: ! partitioning of the vector is determined by PETSc at runtime.
59: !
60: ! Routines for creating particular vector types directly are:
61: ! VecCreateSeq() - uniprocessor vector
62: ! VecCreateMPI() - distributed vector, where the user can
63: ! determine the parallel partitioning
65: call VecCreate(PETSC_COMM_WORLD,x,ierr);CHKERRA(ierr)
66: call VecSetSizes(x,PETSC_DECIDE,n,ierr);CHKERRA(ierr)
67: call VecSetFromOptions(x,ierr);CHKERRA(ierr)
69: ! Duplicate some work vectors (of the same format and
70: ! partitioning as the initial vector).
72: call VecDuplicate(x,y,ierr);CHKERRA(ierr)
73: call VecDuplicate(x,w,ierr);CHKERRA(ierr)
75: ! Duplicate more work vectors (of the same format and
76: ! partitioning as the initial vector). Here we duplicate
77: ! an array of vectors, which is often more convenient than
78: ! duplicating individual ones.
80: call VecDuplicateVecsF90(x,ithree,z,ierr);CHKERRA(ierr)
82: ! Set the vectors to entries to a constant value.
84: call VecSet(x,one,ierr);CHKERRA(ierr)
85: call VecSet(y,two,ierr);CHKERRA(ierr)
86: call VecSet(z(1),one,ierr);CHKERRA(ierr)
87: call VecSet(z(2),two,ierr);CHKERRA(ierr)
88: call VecSet(z(3),three,ierr);CHKERRA(ierr)
90: ! Demonstrate various basic vector routines.
92: call VecDot(x,x,dot,ierr);CHKERRA(ierr)
93: call VecMDot(x,ithree,z,dots,ierr);CHKERRA(ierr)
95: ! Note: If using a complex numbers version of PETSc, then
96: ! PETSC_USE_COMPLEX is defined in the makefiles; otherwise,
97: ! (when using real numbers) it is undefined.
99: if (rank .eq. 0) then
100: #if defined(PETSC_USE_COMPLEX)
101: write(6,100) int(PetscRealPart(dot))
102: write(6,110) int(PetscRealPart(dots(1))),int(PetscRealPart(dots(2))),int(PetscRealPart(dots(3)))
103: #else
104: write(6,100) int(dot)
105: write(6,110) int(dots(1)),int(dots(2)),int(dots(3))
106: #endif
107: write(6,120)
108: endif
109: 100 format ('Vector length ',i6)
110: 110 format ('Vector length ',3(i6))
111: 120 format ('All other values should be near zero')
113: call VecScale(x,two,ierr);CHKERRA(ierr)
114: call VecNorm(x,NORM_2,norm,ierr);CHKERRA(ierr)
115: v = abs(norm-2.0*sqrt(nfloat))
116: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
117: if (rank .eq. 0) write(6,130) v
118: 130 format ('VecScale ',1pe8.2)
120: call VecCopy(x,w,ierr);CHKERRA(ierr)
121: call VecNorm(w,NORM_2,norm,ierr);CHKERRA(ierr)
122: v = abs(norm-2.0*sqrt(nfloat))
123: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
124: if (rank .eq. 0) write(6,140) v
125: 140 format ('VecCopy ',1pe8.2)
127: call VecAXPY(y,three,x,ierr);CHKERRA(ierr)
128: call VecNorm(y,NORM_2,norm,ierr);CHKERRA(ierr)
129: v = abs(norm-8.0*sqrt(nfloat))
130: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
131: if (rank .eq. 0) write(6,150) v
132: 150 format ('VecAXPY ',1pe8.2)
134: call VecAYPX(y,two,x,ierr);CHKERRA(ierr)
135: call VecNorm(y,NORM_2,norm,ierr);CHKERRA(ierr)
136: v = abs(norm-18.0*sqrt(nfloat))
137: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
138: if (rank .eq. 0) write(6,160) v
139: 160 format ('VecAYXP ',1pe8.2)
141: call VecSwap(x,y,ierr);CHKERRA(ierr)
142: call VecNorm(y,NORM_2,norm,ierr);CHKERRA(ierr)
143: v = abs(norm-2.0*sqrt(nfloat))
144: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
145: if (rank .eq. 0) write(6,170) v
146: 170 format ('VecSwap ',1pe8.2)
148: call VecNorm(x,NORM_2,norm,ierr);CHKERRA(ierr)
149: v = abs(norm-18.0*sqrt(nfloat))
150: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
151: if (rank .eq. 0) write(6,180) v
152: 180 format ('VecSwap ',1pe8.2)
154: call VecWAXPY(w,two,x,y,ierr);CHKERRA(ierr)
155: call VecNorm(w,NORM_2,norm,ierr);CHKERRA(ierr)
156: v = abs(norm-38.0*sqrt(nfloat))
157: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
158: if (rank .eq. 0) write(6,190) v
159: 190 format ('VecWAXPY ',1pe8.2)
161: call VecPointwiseMult(w,y,x,ierr);CHKERRA(ierr)
162: call VecNorm(w,NORM_2,norm,ierr);CHKERRA(ierr)
163: v = abs(norm-36.0*sqrt(nfloat))
164: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
165: if (rank .eq. 0) write(6,200) v
166: 200 format ('VecPointwiseMult ',1pe8.2)
168: call VecPointwiseDivide(w,x,y,ierr);CHKERRA(ierr)
169: call VecNorm(w,NORM_2,norm,ierr);CHKERRA(ierr)
170: v = abs(norm-9.0*sqrt(nfloat))
171: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
172: if (rank .eq. 0) write(6,210) v
173: 210 format ('VecPointwiseDivide ',1pe8.2)
176: dots(1) = one
177: dots(2) = three
178: dots(3) = two
179: call VecSet(x,one,ierr);CHKERRA(ierr)
180: call VecMAXPY(x,ithree,dots,z,ierr);CHKERRA(ierr)
181: call VecNorm(z(1),NORM_2,norm,ierr);CHKERRA(ierr)
182: v = abs(norm-sqrt(nfloat))
183: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
184: call VecNorm(z(2),NORM_2,norm,ierr);CHKERRA(ierr)
185: v1 = abs(norm-2.0*sqrt(nfloat))
186: if (v1 .gt. -1.d-10 .and. v1 .lt. 1.d-10) v1 = 0.0
187: call VecNorm(z(3),NORM_2,norm,ierr);CHKERRA(ierr)
188: v2 = abs(norm-3.0*sqrt(nfloat))
189: if (v2 .gt. -1.d-10 .and. v2 .lt. 1.d-10) v2 = 0.0
190: if (rank .eq. 0) write(6,220) v,v1,v2
191: 220 format ('VecMAXPY ',3(1pe8.2))
193: ! Free work space. All PETSc objects should be destroyed when they
194: ! are no longer needed.
196: call VecDestroy(x,ierr);CHKERRA(ierr)
197: call VecDestroy(y,ierr);CHKERRA(ierr)
198: call VecDestroy(w,ierr);CHKERRA(ierr)
199: call VecDestroyVecsF90(ithree,z,ierr);CHKERRA(ierr)
200: call PetscFinalize(ierr)
202: end