Actual source code: ex20f90.F90
petsc-3.12.5 2020-03-29
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
13: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
14: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
15: !
16: !
17: ! This examples uses Fortran 90 MODULES instead of include files
18: ! see the manual page UsingFortran
19: !
20: #include <petsc/finclude/petscvec.h>
21: use petscvec
22: implicit none
24: !
25: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
26: ! Variable declarations
27: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
28: !
29: ! Variables:
30: ! x, y, w - vectors
31: ! z - array of vectors
32: !
33: type(tVec) x,y,w
34: type(tVec), pointer :: z(:)
36: PetscReal norm,v,v1,v2,tol
37: PetscInt n,ithree
38: PetscErrorCode ierr
39: PetscMPIInt rank
40: PetscBool flg
41: PetscScalar one,two,three
42: PetscScalar dots(3),dot
43: PetscReal nfloat
45: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
46: ! Beginning of program
47: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
49: call PetscInitialize(PETSC_NULL_CHARACTER,ierr)
50: if (ierr .ne. 0) then
51: print*,'Unable to initialize PETSc'
52: stop
53: endif
55: tol = 1.e-10_PETSC_REAL_KIND
56: one = 1.0
57: two = 2.0
58: three = 3.0
59: n = 20
60: ithree = 3
62: call PetscOptionsGetInt(PETSC_NULL_OPTIONS,PETSC_NULL_CHARACTER,'-n',n,flg,ierr);CHKERRA(ierr)
63: nfloat = n
64: call MPI_Comm_rank(PETSC_COMM_WORLD,rank,ierr);CHKERRA(ierr)
66: ! Create a vector, specifying only its global dimension.
67: ! When using VecCreate(), VecSetSizes() and VecSetFromOptions(),
68: ! the vector format (currently parallel
69: ! or sequential) is determined at runtime. Also, the parallel
70: ! partitioning of the vector is determined by PETSc at runtime.
71: !
72: ! Routines for creating particular vector types directly are:
73: ! VecCreateSeq() - uniprocessor vector
74: ! VecCreateMPI() - distributed vector, where the user can
75: ! determine the parallel partitioning
77: call VecCreate(PETSC_COMM_WORLD,x,ierr);CHKERRA(ierr)
78: call VecSetSizes(x,PETSC_DECIDE,n,ierr);CHKERRA(ierr)
79: call VecSetFromOptions(x,ierr);CHKERRA(ierr)
81: ! Duplicate some work vectors (of the same format and
82: ! partitioning as the initial vector).
84: call VecDuplicate(x,y,ierr);CHKERRA(ierr)
85: call VecDuplicate(x,w,ierr);CHKERRA(ierr)
87: ! Duplicate more work vectors (of the same format and
88: ! partitioning as the initial vector). Here we duplicate
89: ! an array of vectors, which is often more convenient than
90: ! duplicating individual ones.
92: call VecDuplicateVecsF90(x,ithree,z,ierr);CHKERRA(ierr)
94: ! Set the vectors to entries to a constant value.
96: call VecSet(x,one,ierr);CHKERRA(ierr)
97: call VecSet(y,two,ierr);CHKERRA(ierr)
98: call VecSet(z(1),one,ierr);CHKERRA(ierr)
99: call VecSet(z(2),two,ierr);CHKERRA(ierr)
100: call VecSet(z(3),three,ierr);CHKERRA(ierr)
102: ! Demonstrate various basic vector routines.
104: call VecDot(x,x,dot,ierr);CHKERRA(ierr)
105: call VecMDot(x,ithree,z,dots,ierr);CHKERRA(ierr)
107: ! Note: If using a complex numbers version of PETSc, then
108: ! PETSC_USE_COMPLEX is defined in the makefiles; otherwise,
109: ! (when using real numbers) it is undefined.
111: if (rank .eq. 0) then
112: #if defined(PETSC_USE_COMPLEX)
113: write(6,100) int(PetscRealPart(dot))
114: write(6,110) int(PetscRealPart(dots(1))),int(PetscRealPart(dots(2))),int(PetscRealPart(dots(3)))
115: #else
116: write(6,100) int(dot)
117: write(6,110) int(dots(1)),int(dots(2)),int(dots(3))
118: #endif
119: write(6,120)
120: endif
121: 100 format ('Vector length ',i6)
122: 110 format ('Vector length ',3(i6))
123: 120 format ('All other values should be near zero')
125: call VecScale(x,two,ierr);CHKERRA(ierr)
126: call VecNorm(x,NORM_2,norm,ierr);CHKERRA(ierr)
127: v = abs(norm-2.0*sqrt(nfloat))
128: if (v .gt. -tol .and. v .lt. tol) v = 0.0
129: if (rank .eq. 0) write(6,130) v
130: 130 format ('VecScale ',1pe9.2)
132: call VecCopy(x,w,ierr);CHKERRA(ierr)
133: call VecNorm(w,NORM_2,norm,ierr);CHKERRA(ierr)
134: v = abs(norm-2.0*sqrt(nfloat))
135: if (v .gt. -tol .and. v .lt. tol) v = 0.0
136: if (rank .eq. 0) write(6,140) v
137: 140 format ('VecCopy ',1pe9.2)
139: call VecAXPY(y,three,x,ierr);CHKERRA(ierr)
140: call VecNorm(y,NORM_2,norm,ierr);CHKERRA(ierr)
141: v = abs(norm-8.0*sqrt(nfloat))
142: if (v .gt. -tol .and. v .lt. tol) v = 0.0
143: if (rank .eq. 0) write(6,150) v
144: 150 format ('VecAXPY ',1pe9.2)
146: call VecAYPX(y,two,x,ierr);CHKERRA(ierr)
147: call VecNorm(y,NORM_2,norm,ierr);CHKERRA(ierr)
148: v = abs(norm-18.0*sqrt(nfloat))
149: if (v .gt. -tol .and. v .lt. tol) v = 0.0
150: if (rank .eq. 0) write(6,160) v
151: 160 format ('VecAYXP ',1pe9.2)
153: call VecSwap(x,y,ierr);CHKERRA(ierr)
154: call VecNorm(y,NORM_2,norm,ierr);CHKERRA(ierr)
155: v = abs(norm-2.0*sqrt(nfloat))
156: if (v .gt. -tol .and. v .lt. tol) v = 0.0
157: if (rank .eq. 0) write(6,170) v
158: 170 format ('VecSwap ',1pe9.2)
160: call VecNorm(x,NORM_2,norm,ierr);CHKERRA(ierr)
161: v = abs(norm-18.0*sqrt(nfloat))
162: if (v .gt. -tol .and. v .lt. tol) v = 0.0
163: if (rank .eq. 0) write(6,180) v
164: 180 format ('VecSwap ',1pe9.2)
166: call VecWAXPY(w,two,x,y,ierr);CHKERRA(ierr)
167: call VecNorm(w,NORM_2,norm,ierr);CHKERRA(ierr)
168: v = abs(norm-38.0*sqrt(nfloat))
169: if (v .gt. -tol .and. v .lt. tol) v = 0.0
170: if (rank .eq. 0) write(6,190) v
171: 190 format ('VecWAXPY ',1pe9.2)
173: call VecPointwiseMult(w,y,x,ierr);CHKERRA(ierr)
174: call VecNorm(w,NORM_2,norm,ierr);CHKERRA(ierr)
175: v = abs(norm-36.0*sqrt(nfloat))
176: if (v .gt. -tol .and. v .lt. tol) v = 0.0
177: if (rank .eq. 0) write(6,200) v
178: 200 format ('VecPointwiseMult ',1pe9.2)
180: call VecPointwiseDivide(w,x,y,ierr);CHKERRA(ierr)
181: call VecNorm(w,NORM_2,norm,ierr);CHKERRA(ierr)
182: v = abs(norm-9.0*sqrt(nfloat))
183: if (v .gt. -tol .and. v .lt. tol) v = 0.0
184: if (rank .eq. 0) write(6,210) v
185: 210 format ('VecPointwiseDivide ',1pe9.2)
188: dots(1) = one
189: dots(2) = three
190: dots(3) = two
191: call VecSet(x,one,ierr);CHKERRA(ierr)
192: call VecMAXPY(x,ithree,dots,z,ierr);CHKERRA(ierr)
193: call VecNorm(z(1),NORM_2,norm,ierr);CHKERRA(ierr)
194: v = abs(norm-sqrt(nfloat))
195: if (v .gt. -tol .and. v .lt. tol) v = 0.0
196: call VecNorm(z(2),NORM_2,norm,ierr);CHKERRA(ierr)
197: v1 = abs(norm-2.0*sqrt(nfloat))
198: if (v1 .gt. -tol .and. v1 .lt. tol) v1 = 0.0
199: call VecNorm(z(3),NORM_2,norm,ierr);CHKERRA(ierr)
200: v2 = abs(norm-3.0*sqrt(nfloat))
201: if (v2 .gt. -tol .and. v2 .lt. tol) v2 = 0.0
202: if (rank .eq. 0) write(6,220) v,v1,v2
203: 220 format ('VecMAXPY ',3(1pe9.2))
206: ! Free work space. All PETSc objects should be destroyed when they
207: ! are no longer needed.
209: call VecDestroy(x,ierr);CHKERRA(ierr)
210: call VecDestroy(y,ierr);CHKERRA(ierr)
211: call VecDestroy(w,ierr);CHKERRA(ierr)
212: call VecDestroyVecsF90(ithree,z,ierr);CHKERRA(ierr)
213: call PetscFinalize(ierr)
215: end
217: !/*TEST
218: !
219: ! test:
220: !
221: !TEST*/