xref: /libCEED/rust/libceed/src/vector.rs (revision 56e67e05b44fa4372f54ad04a6858fe2bd975779)
1 // Copyright (c) 2017, Lawrence Livermore National Security, LLC. Produced at
2 // the Lawrence Livermore National Laboratory. LLNL-CODE-734707. All Rights
3 // reserved. See files LICENSE and NOTICE for details.
4 //
5 // This file is part of CEED, a collection of benchmarks, miniapps, software
6 // libraries and APIs for efficient high-order finite element and spectral
7 // element discretizations for exascale applications. For more information and
8 // source code availability see http://github.com/ceed.
9 //
10 // The CEED research is supported by the Exascale Computing Project 17-SC-20-SC,
11 // a collaborative effort of two U.S. Department of Energy organizations (Office
12 // of Science and the National Nuclear Security Administration) responsible for
13 // the planning and preparation of a capable exascale ecosystem, including
14 // software, applications, hardware, advanced system engineering and early
15 // testbed platforms, in support of the nation's exascale computing imperative
16 
17 //! A Ceed Vector constitutes the main data structure and serves as input/output
18 //! for Ceed Operators.
19 
20 use std::{
21     ops::{Deref, DerefMut},
22     os::raw::c_char,
23 };
24 
25 use crate::prelude::*;
26 
27 // -----------------------------------------------------------------------------
28 // CeedVector option
29 // -----------------------------------------------------------------------------
30 #[derive(Debug)]
31 pub enum VectorOpt<'a> {
32     Some(&'a Vector<'a>),
33     Active,
34     None,
35 }
36 /// Construct a VectorOpt reference from a Vector reference
37 impl<'a> From<&'a Vector<'_>> for VectorOpt<'a> {
38     fn from(vec: &'a Vector) -> Self {
39         debug_assert!(vec.ptr != unsafe { bind_ceed::CEED_VECTOR_ACTIVE });
40         debug_assert!(vec.ptr != unsafe { bind_ceed::CEED_VECTOR_NONE });
41         Self::Some(vec)
42     }
43 }
44 impl<'a> VectorOpt<'a> {
45     /// Transform a Rust libCEED VectorOpt into C libCEED CeedVector
46     pub(crate) fn to_raw(self) -> bind_ceed::CeedVector {
47         match self {
48             Self::Some(vec) => vec.ptr,
49             Self::Active => unsafe { bind_ceed::CEED_VECTOR_ACTIVE },
50             Self::None => unsafe { bind_ceed::CEED_VECTOR_NONE },
51         }
52     }
53 
54     /// Check if a VectorOpt is Some
55     ///
56     /// ```
57     /// # use libceed::prelude::*;
58     /// # fn main() -> libceed::Result<()> {
59     /// # let ceed = libceed::Ceed::default_init();
60     /// let vec = libceed::vector::Vector::from_slice(&ceed, &[1., 2., 3.])?;
61     /// let vec_opt = VectorOpt::from(&vec);
62     /// assert!(vec_opt.is_some(), "Incorrect VectorOpt");
63     ///
64     /// let vec_opt = VectorOpt::Active;
65     /// assert!(!vec_opt.is_some(), "Incorrect VectorOpt");
66     ///
67     /// let vec_opt = VectorOpt::None;
68     /// assert!(!vec_opt.is_some(), "Incorrect VectorOpt");
69     /// # Ok(())
70     /// # }
71     /// ```
72     pub fn is_some(&self) -> bool {
73         match self {
74             Self::Some(_) => true,
75             Self::Active => false,
76             Self::None => false,
77         }
78     }
79 
80     /// Check if a VectorOpt is Active
81     ///
82     /// ```
83     /// # use libceed::prelude::*;
84     /// # fn main() -> libceed::Result<()> {
85     /// # let ceed = libceed::Ceed::default_init();
86     /// let vec = libceed::vector::Vector::from_slice(&ceed, &[1., 2., 3.])?;
87     /// let vec_opt = VectorOpt::from(&vec);
88     /// assert!(!vec_opt.is_active(), "Incorrect VectorOpt");
89     ///
90     /// let vec_opt = VectorOpt::Active;
91     /// assert!(vec_opt.is_active(), "Incorrect VectorOpt");
92     ///
93     /// let vec_opt = VectorOpt::None;
94     /// assert!(!vec_opt.is_active(), "Incorrect VectorOpt");
95     /// # Ok(())
96     /// # }
97     /// ```
98     pub fn is_active(&self) -> bool {
99         match self {
100             Self::Some(_) => false,
101             Self::Active => true,
102             Self::None => false,
103         }
104     }
105 
106     /// Check if a VectorOpt is Some
107     ///
108     /// ```
109     /// # use libceed::prelude::*;
110     /// # fn main() -> libceed::Result<()> {
111     /// # let ceed = libceed::Ceed::default_init();
112     /// let vec = libceed::vector::Vector::from_slice(&ceed, &[1., 2., 3.])?;
113     /// let vec_opt = VectorOpt::from(&vec);
114     /// assert!(!vec_opt.is_none(), "Incorrect VectorOpt");
115     ///
116     /// let vec_opt = VectorOpt::Active;
117     /// assert!(!vec_opt.is_none(), "Incorrect VectorOpt");
118     ///
119     /// let vec_opt = VectorOpt::None;
120     /// assert!(vec_opt.is_none(), "Incorrect VectorOpt");
121     /// # Ok(())
122     /// # }
123     /// ```
124     pub fn is_none(&self) -> bool {
125         match self {
126             Self::Some(_) => false,
127             Self::Active => false,
128             Self::None => true,
129         }
130     }
131 }
132 
133 // -----------------------------------------------------------------------------
134 // CeedVector borrowed slice wrapper
135 // -----------------------------------------------------------------------------
136 pub struct VectorSliceBorrow<'a> {
137     pub(crate) vector: crate::Vector<'a>,
138     pub(crate) _slice: &'a mut [crate::Scalar],
139 }
140 
141 // -----------------------------------------------------------------------------
142 // Destructor
143 // -----------------------------------------------------------------------------
144 impl<'a> Drop for VectorSliceBorrow<'a> {
145     fn drop(&mut self) {
146         unsafe {
147             bind_ceed::CeedVectorTakeArray(
148                 self.vector.ptr,
149                 crate::MemType::Host as bind_ceed::CeedMemType,
150                 std::ptr::null_mut(),
151             )
152         };
153     }
154 }
155 
156 // -----------------------------------------------------------------------------
157 // CeedVector context wrapper
158 // -----------------------------------------------------------------------------
159 #[derive(Debug)]
160 pub struct Vector<'a> {
161     pub(crate) ptr: bind_ceed::CeedVector,
162     _lifeline: PhantomData<&'a ()>,
163 }
164 impl From<&'_ Vector<'_>> for bind_ceed::CeedVector {
165     fn from(vec: &Vector) -> Self {
166         vec.ptr
167     }
168 }
169 
170 // -----------------------------------------------------------------------------
171 // Destructor
172 // -----------------------------------------------------------------------------
173 impl<'a> Drop for Vector<'a> {
174     fn drop(&mut self) {
175         let not_none_and_active = self.ptr != unsafe { bind_ceed::CEED_VECTOR_NONE }
176             && self.ptr != unsafe { bind_ceed::CEED_VECTOR_ACTIVE };
177 
178         if not_none_and_active {
179             unsafe { bind_ceed::CeedVectorDestroy(&mut self.ptr) };
180         }
181     }
182 }
183 
184 // -----------------------------------------------------------------------------
185 // Display
186 // -----------------------------------------------------------------------------
187 impl<'a> fmt::Display for Vector<'a> {
188     /// View a Vector
189     ///
190     /// ```
191     /// # use libceed::prelude::*;
192     /// # fn main() -> libceed::Result<()> {
193     /// # let ceed = libceed::Ceed::default_init();
194     /// let vec = libceed::vector::Vector::from_slice(&ceed, &[1., 2., 3.])?;
195     /// assert_eq!(
196     ///     vec.to_string(),
197     ///     "CeedVector length 3
198     ///     1.00000000
199     ///     2.00000000
200     ///     3.00000000
201     /// "
202     /// );
203     /// # Ok(())
204     /// # }
205     /// ```
206     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
207         let mut ptr = std::ptr::null_mut();
208         let mut sizeloc = crate::MAX_BUFFER_LENGTH;
209         let format = CString::new("%12.8f").expect("CString::new failed");
210         let format_c: *const c_char = format.into_raw();
211         let cstring = unsafe {
212             let file = bind_ceed::open_memstream(&mut ptr, &mut sizeloc);
213             bind_ceed::CeedVectorView(self.ptr, format_c, file);
214             bind_ceed::fclose(file);
215             CString::from_raw(ptr)
216         };
217         cstring.to_string_lossy().fmt(f)
218     }
219 }
220 
221 // -----------------------------------------------------------------------------
222 // Implementations
223 // -----------------------------------------------------------------------------
224 impl<'a> Vector<'a> {
225     // Constructors
226     pub fn create(ceed: &'a crate::Ceed, n: usize) -> crate::Result<Self> {
227         let n = i32::try_from(n).unwrap();
228         let mut ptr = std::ptr::null_mut();
229         let ierr = unsafe { bind_ceed::CeedVectorCreate(ceed.ptr, n, &mut ptr) };
230         ceed.check_error(ierr)?;
231         Ok(Self {
232             ptr,
233             _lifeline: PhantomData,
234         })
235     }
236 
237     pub(crate) fn from_raw(ptr: bind_ceed::CeedVector) -> crate::Result<Self> {
238         Ok(Self {
239             ptr,
240             _lifeline: PhantomData,
241         })
242     }
243 
244     /// Create a Vector from a slice
245     ///
246     /// # arguments
247     ///
248     /// * `slice` - values to initialize vector with
249     ///
250     /// ```
251     /// # use libceed::prelude::*;
252     /// # fn main() -> libceed::Result<()> {
253     /// # let ceed = libceed::Ceed::default_init();
254     /// let vec = vector::Vector::from_slice(&ceed, &[1., 2., 3.])?;
255     /// assert_eq!(vec.length(), 3, "Incorrect length from slice");
256     /// # Ok(())
257     /// # }
258     /// ```
259     pub fn from_slice(ceed: &'a crate::Ceed, v: &[crate::Scalar]) -> crate::Result<Self> {
260         let mut x = Self::create(ceed, v.len())?;
261         x.set_slice(v)?;
262         Ok(x)
263     }
264 
265     /// Create a Vector from a mutable array reference
266     ///
267     /// # arguments
268     ///
269     /// * `slice` - values to initialize vector with
270     ///
271     /// ```
272     /// # use libceed::prelude::*;
273     /// # fn main() -> libceed::Result<()> {
274     /// # let ceed = libceed::Ceed::default_init();
275     /// let mut rust_vec = vec![1., 2., 3.];
276     /// let vec = libceed::vector::Vector::from_array(&ceed, &mut rust_vec)?;
277     ///
278     /// assert_eq!(vec.length(), 3, "Incorrect length from slice");
279     /// # Ok(())
280     /// # }
281     /// ```
282     pub fn from_array(ceed: &'a crate::Ceed, v: &mut [crate::Scalar]) -> crate::Result<Self> {
283         let x = Self::create(ceed, v.len())?;
284         let (host, user_pointer) = (
285             crate::MemType::Host as bind_ceed::CeedMemType,
286             crate::CopyMode::UsePointer as bind_ceed::CeedCopyMode,
287         );
288         let v = v.as_ptr() as *mut crate::Scalar;
289         let ierr = unsafe { bind_ceed::CeedVectorSetArray(x.ptr, host, user_pointer, v) };
290         ceed.check_error(ierr)?;
291         Ok(x)
292     }
293 
294     // Error handling
295     #[doc(hidden)]
296     fn check_error(&self, ierr: i32) -> crate::Result<i32> {
297         let mut ptr = std::ptr::null_mut();
298         unsafe {
299             bind_ceed::CeedVectorGetCeed(self.ptr, &mut ptr);
300         }
301         crate::check_error(ptr, ierr)
302     }
303 
304     /// Returns the length of a CeedVector
305     ///
306     /// ```
307     /// # use libceed::prelude::*;
308     /// # fn main() -> libceed::Result<()> {
309     /// # let ceed = libceed::Ceed::default_init();
310     /// let vec = ceed.vector(10)?;
311     ///
312     /// let n = vec.length();
313     /// assert_eq!(n, 10, "Incorrect length");
314     /// # Ok(())
315     /// # }
316     /// ```
317     pub fn length(&self) -> usize {
318         let mut n = 0;
319         unsafe { bind_ceed::CeedVectorGetLength(self.ptr, &mut n) };
320         usize::try_from(n).unwrap()
321     }
322 
323     /// Returns the length of a CeedVector
324     ///
325     /// ```
326     /// # use libceed::prelude::*;
327     /// # fn main() -> libceed::Result<()> {
328     /// # let ceed = libceed::Ceed::default_init();
329     /// let vec = ceed.vector(10)?;
330     /// assert_eq!(vec.len(), 10, "Incorrect length");
331     /// # Ok(())
332     /// # }
333     /// ```
334     pub fn len(&self) -> usize {
335         self.length()
336     }
337 
338     /// Set the CeedVector to a constant value
339     ///
340     /// # arguments
341     ///
342     /// * `val` - Value to be used
343     ///
344     /// ```
345     /// # use libceed::prelude::*;
346     /// # fn main() -> libceed::Result<()> {
347     /// # let ceed = libceed::Ceed::default_init();
348     /// let len = 10;
349     /// let mut vec = ceed.vector(len)?;
350     ///
351     /// let val = 42.0;
352     /// vec.set_value(val)?;
353     ///
354     /// vec.view()?.iter().for_each(|v| {
355     ///     assert_eq!(*v, val, "Value not set correctly");
356     /// });
357     /// # Ok(())
358     /// # }
359     /// ```
360     pub fn set_value(&mut self, value: crate::Scalar) -> crate::Result<i32> {
361         let ierr = unsafe { bind_ceed::CeedVectorSetValue(self.ptr, value) };
362         self.check_error(ierr)
363     }
364 
365     /// Set values from a slice of the same length
366     ///
367     /// # arguments
368     ///
369     /// * `slice` - values to into self; length must match
370     ///
371     /// ```
372     /// # use libceed::prelude::*;
373     /// # fn main() -> libceed::Result<()> {
374     /// # let ceed = libceed::Ceed::default_init();
375     /// let mut vec = ceed.vector(4)?;
376     /// vec.set_slice(&[10., 11., 12., 13.])?;
377     ///
378     /// vec.view()?.iter().enumerate().for_each(|(i, v)| {
379     ///     assert_eq!(*v, 10. + i as Scalar, "Slice not set correctly");
380     /// });
381     /// # Ok(())
382     /// # }
383     /// ```
384     pub fn set_slice(&mut self, slice: &[crate::Scalar]) -> crate::Result<i32> {
385         assert_eq!(self.length(), slice.len());
386         let (host, copy_mode) = (
387             crate::MemType::Host as bind_ceed::CeedMemType,
388             crate::CopyMode::CopyValues as bind_ceed::CeedCopyMode,
389         );
390         let ierr = unsafe {
391             bind_ceed::CeedVectorSetArray(
392                 self.ptr,
393                 host,
394                 copy_mode,
395                 slice.as_ptr() as *mut crate::Scalar,
396             )
397         };
398         self.check_error(ierr)
399     }
400 
401     /// Set Vector array to borrowed slice of the same length
402     ///
403     /// # arguments
404     ///
405     /// * `slice` - values to into self; length must match
406     ///
407     /// ```
408     /// # use libceed::prelude::*;
409     /// # fn main() -> libceed::Result<()> {
410     /// # let ceed = libceed::Ceed::default_init();
411     /// let mut vec = ceed.vector(4)?;
412     /// let mut slice = vec![10., 11., 12., 13.];
413     ///
414     /// {
415     ///     // `borrow` holds a mutable reference to the slice
416     ///     let borrow = vec.set_borrowed_slice(&mut slice)?;
417     ///     vec.view()?.iter().enumerate().for_each(|(i, v)| {
418     ///         assert_eq!(*v, 10. + i as Scalar, "Slice not set correctly");
419     ///     });
420     ///
421     ///     // This line will not compile, as the `borrow` is still in scope
422     ///     // slice[0] = 5.0;
423     ///
424     ///     // Changes here are reflected in the `slice`
425     ///     vec.set_value(5.0)?;
426     ///     vec.view()?.iter().for_each(|v| {
427     ///         assert_eq!(*v, 5 as Scalar, "Slice not set correctly");
428     ///     });
429     /// }
430     ///
431     /// // Slice remains changed
432     /// slice.iter().for_each(|v| {
433     ///     assert_eq!(*v, 5 as Scalar, "Slice not set correctly");
434     /// });
435     ///
436     /// // This line will error, as the Vector has dropped the reference
437     /// //   to the slice and no new array was allocated for the Vector
438     /// // vec.view()?;
439     /// # Ok(())
440     /// # }
441     /// ```
442     pub fn set_borrowed_slice<'b>(
443         &mut self,
444         slice: &'b mut [crate::Scalar],
445     ) -> crate::Result<VectorSliceBorrow<'b>> {
446         assert_eq!(self.length(), slice.len());
447         let (host, copy_mode) = (
448             crate::MemType::Host as bind_ceed::CeedMemType,
449             crate::CopyMode::UsePointer as bind_ceed::CeedCopyMode,
450         );
451         let ierr = unsafe {
452             bind_ceed::CeedVectorSetArray(
453                 self.ptr,
454                 host,
455                 copy_mode,
456                 slice.as_ptr() as *mut crate::Scalar,
457             )
458         };
459         self.check_error(ierr)?;
460 
461         let mut ptr_copy = std::ptr::null_mut();
462         let ierr = unsafe { bind_ceed::CeedVectorReferenceCopy(self.ptr, &mut ptr_copy) };
463         self.check_error(ierr)?;
464 
465         Ok(crate::VectorSliceBorrow {
466             vector: crate::Vector::from_raw(ptr_copy)?,
467             _slice: slice,
468         })
469     }
470 
471     /// Sync the CeedVector to a specified memtype
472     ///
473     /// # arguments
474     ///
475     /// * `mtype` - Memtype to be synced
476     ///
477     /// ```
478     /// # use libceed::prelude::*;
479     /// # fn main() -> libceed::Result<()> {
480     /// # let ceed = libceed::Ceed::default_init();
481     /// let len = 10;
482     /// let mut vec = ceed.vector(len)?;
483     ///
484     /// let val = 42.0;
485     /// vec.set_value(val);
486     /// vec.sync(MemType::Host)?;
487     ///
488     /// vec.view()?.iter().for_each(|v| {
489     ///     assert_eq!(*v, val, "Value not set correctly");
490     /// });
491     /// # Ok(())
492     /// # }
493     /// ```
494     pub fn sync(&self, mtype: crate::MemType) -> crate::Result<i32> {
495         let ierr =
496             unsafe { bind_ceed::CeedVectorSyncArray(self.ptr, mtype as bind_ceed::CeedMemType) };
497         self.check_error(ierr)
498     }
499 
500     /// Create an immutable view
501     ///
502     /// ```
503     /// # use libceed::prelude::*;
504     /// # fn main() -> libceed::Result<()> {
505     /// # let ceed = libceed::Ceed::default_init();
506     /// let vec = ceed.vector_from_slice(&[10., 11., 12., 13.])?;
507     ///
508     /// let v = vec.view()?;
509     /// assert_eq!(v[0..2], [10., 11.]);
510     ///
511     /// // It is valid to have multiple immutable views
512     /// let w = vec.view()?;
513     /// assert_eq!(v[1..], w[1..]);
514     /// # Ok(())
515     /// # }
516     /// ```
517     pub fn view(&self) -> crate::Result<VectorView> {
518         VectorView::new(self)
519     }
520 
521     /// Create an mutable view
522     ///
523     /// ```
524     /// # use libceed::prelude::*;
525     /// # fn main() -> libceed::Result<()> {
526     /// # let ceed = libceed::Ceed::default_init();
527     /// let mut vec = ceed.vector_from_slice(&[10., 11., 12., 13.])?;
528     ///
529     /// {
530     ///     let mut v = vec.view_mut()?;
531     ///     v[2] = 9.;
532     /// }
533     ///
534     /// let w = vec.view()?;
535     /// assert_eq!(w[2], 9., "View did not mutate data");
536     /// # Ok(())
537     /// # }
538     /// ```
539     pub fn view_mut(&mut self) -> crate::Result<VectorViewMut> {
540         VectorViewMut::new(self)
541     }
542 
543     /// Return the norm of a CeedVector
544     ///
545     /// # arguments
546     ///
547     /// * `ntype` - Norm type One, Two, or Max
548     ///
549     /// ```
550     /// # use libceed::prelude::*;
551     /// # fn main() -> libceed::Result<()> {
552     /// # let ceed = libceed::Ceed::default_init();
553     /// let vec = ceed.vector_from_slice(&[1., 2., 3., 4.])?;
554     ///
555     /// let max_norm = vec.norm(NormType::Max)?;
556     /// assert_eq!(max_norm, 4.0, "Incorrect Max norm");
557     ///
558     /// let l1_norm = vec.norm(NormType::One)?;
559     /// assert_eq!(l1_norm, 10., "Incorrect L1 norm");
560     ///
561     /// let l2_norm = vec.norm(NormType::Two)?;
562     /// assert!((l2_norm - 5.477) < 1e-3, "Incorrect L2 norm");
563     /// # Ok(())
564     /// # }
565     /// ```
566     pub fn norm(&self, ntype: crate::NormType) -> crate::Result<crate::Scalar> {
567         let mut res: crate::Scalar = 0.0;
568         let ierr = unsafe {
569             bind_ceed::CeedVectorNorm(self.ptr, ntype as bind_ceed::CeedNormType, &mut res)
570         };
571         self.check_error(ierr)?;
572         Ok(res)
573     }
574 
575     /// Compute x = alpha x for a CeedVector
576     ///
577     /// # arguments
578     ///
579     /// * `alpha` - scaling factor
580     ///
581     /// ```
582     /// # use libceed::prelude::*;
583     /// # fn main() -> libceed::Result<()> {
584     /// # let ceed = libceed::Ceed::default_init();
585     /// let mut vec = ceed.vector_from_slice(&[0., 1., 2., 3., 4.])?;
586     ///
587     /// vec = vec.scale(-1.0)?;
588     /// vec.view()?.iter().enumerate().for_each(|(i, &v)| {
589     ///     assert_eq!(v, -(i as Scalar), "Value not set correctly");
590     /// });
591     /// # Ok(())
592     /// # }
593     /// ```
594     #[allow(unused_mut)]
595     pub fn scale(mut self, alpha: crate::Scalar) -> crate::Result<Self> {
596         let ierr = unsafe { bind_ceed::CeedVectorScale(self.ptr, alpha) };
597         self.check_error(ierr)?;
598         Ok(self)
599     }
600 
601     /// Compute y = alpha x + y for a pair of CeedVectors
602     ///
603     /// # arguments
604     ///
605     /// * `alpha` - scaling factor
606     /// * `x`     - second vector, must be different than self
607     ///
608     /// ```
609     /// # use libceed::prelude::*;
610     /// # fn main() -> libceed::Result<()> {
611     /// # let ceed = libceed::Ceed::default_init();
612     /// let x = ceed.vector_from_slice(&[0., 1., 2., 3., 4.])?;
613     /// let mut y = ceed.vector_from_slice(&[0., 1., 2., 3., 4.])?;
614     ///
615     /// y = y.axpy(-0.5, &x)?;
616     /// y.view()?.iter().enumerate().for_each(|(i, &v)| {
617     ///     assert_eq!(v, (i as Scalar) / 2.0, "Value not set correctly");
618     /// });
619     /// # Ok(())
620     /// # }
621     /// ```
622     #[allow(unused_mut)]
623     pub fn axpy(mut self, alpha: crate::Scalar, x: &crate::Vector) -> crate::Result<Self> {
624         let ierr = unsafe { bind_ceed::CeedVectorAXPY(self.ptr, alpha, x.ptr) };
625         self.check_error(ierr)?;
626         Ok(self)
627     }
628 
629     /// Compute the pointwise multiplication w = x .* y for CeedVectors
630     ///
631     /// # arguments
632     ///
633     /// * `x` - first vector for product
634     /// * `y` - second vector for product
635     ///
636     /// ```
637     /// # use libceed::prelude::*;
638     /// # fn main() -> libceed::Result<()> {
639     /// # let ceed = libceed::Ceed::default_init();
640     /// let mut w = ceed.vector_from_slice(&[0., 1., 2., 3., 4.])?;
641     /// let x = ceed.vector_from_slice(&[0., 1., 2., 3., 4.])?;
642     /// let y = ceed.vector_from_slice(&[0., 1., 2., 3., 4.])?;
643     ///
644     /// w = w.pointwise_mult(&x, &y)?;
645     /// w.view()?.iter().enumerate().for_each(|(i, &v)| {
646     ///     assert_eq!(v, (i as Scalar).powf(2.0), "Value not set correctly");
647     /// });
648     /// # Ok(())
649     /// # }
650     /// ```
651     #[allow(unused_mut)]
652     pub fn pointwise_mult(mut self, x: &crate::Vector, y: &crate::Vector) -> crate::Result<Self> {
653         let ierr = unsafe { bind_ceed::CeedVectorPointwiseMult(self.ptr, x.ptr, y.ptr) };
654         self.check_error(ierr)?;
655         Ok(self)
656     }
657 
658     /// Compute the pointwise multiplication w = w .* x for CeedVectors
659     ///
660     /// # arguments
661     ///
662     /// * `x` - second vector for product
663     ///
664     /// ```
665     /// # use libceed::prelude::*;
666     /// # fn main() -> libceed::Result<()> {
667     /// # let ceed = libceed::Ceed::default_init();
668     /// let mut w = ceed.vector_from_slice(&[0., 1., 2., 3., 4.])?;
669     /// let x = ceed.vector_from_slice(&[0., 1., 2., 3., 4.])?;
670     ///
671     /// w = w.pointwise_scale(&x)?;
672     /// w.view()?.iter().enumerate().for_each(|(i, &v)| {
673     ///     assert_eq!(v, (i as Scalar).powf(2.0), "Value not set correctly");
674     /// });
675     /// # Ok(())
676     /// # }
677     /// ```
678     #[allow(unused_mut)]
679     pub fn pointwise_scale(mut self, x: &crate::Vector) -> crate::Result<Self> {
680         let ierr = unsafe { bind_ceed::CeedVectorPointwiseMult(self.ptr, self.ptr, x.ptr) };
681         self.check_error(ierr)?;
682         Ok(self)
683     }
684 
685     /// Compute the pointwise multiplication w = w .* w for a CeedVector
686     ///
687     /// ```
688     /// # use libceed::prelude::*;
689     /// # fn main() -> libceed::Result<()> {
690     /// # let ceed = libceed::Ceed::default_init();
691     /// let mut w = ceed.vector_from_slice(&[0., 1., 2., 3., 4.])?;
692     ///
693     /// w = w.pointwise_square()?;
694     /// w.view()?.iter().enumerate().for_each(|(i, &v)| {
695     ///     assert_eq!(v, (i as Scalar).powf(2.0), "Value not set correctly");
696     /// });
697     /// # Ok(())
698     /// # }
699     /// ```
700     #[allow(unused_mut)]
701     pub fn pointwise_square(mut self) -> crate::Result<Self> {
702         let ierr = unsafe { bind_ceed::CeedVectorPointwiseMult(self.ptr, self.ptr, self.ptr) };
703         self.check_error(ierr)?;
704         Ok(self)
705     }
706 }
707 
708 // -----------------------------------------------------------------------------
709 // Vector Viewer
710 // -----------------------------------------------------------------------------
711 /// A (host) view of a Vector with Deref to slice.  We can't make
712 /// Vector itself Deref to slice because we can't handle the drop to
713 /// call bind_ceed::CeedVectorRestoreArrayRead().
714 #[derive(Debug)]
715 pub struct VectorView<'a> {
716     vec: &'a Vector<'a>,
717     array: *const crate::Scalar,
718 }
719 
720 impl<'a> VectorView<'a> {
721     /// Construct a VectorView from a Vector reference
722     fn new(vec: &'a Vector) -> crate::Result<Self> {
723         let mut array = std::ptr::null();
724         let ierr = unsafe {
725             bind_ceed::CeedVectorGetArrayRead(
726                 vec.ptr,
727                 crate::MemType::Host as bind_ceed::CeedMemType,
728                 &mut array,
729             )
730         };
731         vec.check_error(ierr)?;
732         Ok(Self {
733             vec: vec,
734             array: array,
735         })
736     }
737 }
738 
739 // Destructor
740 impl<'a> Drop for VectorView<'a> {
741     fn drop(&mut self) {
742         unsafe {
743             bind_ceed::CeedVectorRestoreArrayRead(self.vec.ptr, &mut self.array);
744         }
745     }
746 }
747 
748 // Data access
749 impl<'a> Deref for VectorView<'a> {
750     type Target = [crate::Scalar];
751     fn deref(&self) -> &[crate::Scalar] {
752         unsafe { std::slice::from_raw_parts(self.array, self.vec.len()) }
753     }
754 }
755 
756 // Viewing
757 impl<'a> fmt::Display for VectorView<'a> {
758     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
759         write!(f, "VectorView({:?})", self.deref())
760     }
761 }
762 
763 // -----------------------------------------------------------------------------
764 // Vector Viewer Mutable
765 // -----------------------------------------------------------------------------
766 /// A mutable (host) view of a Vector with Deref to slice.
767 #[derive(Debug)]
768 pub struct VectorViewMut<'a> {
769     vec: &'a Vector<'a>,
770     array: *mut crate::Scalar,
771 }
772 
773 impl<'a> VectorViewMut<'a> {
774     /// Construct a VectorViewMut from a Vector reference
775     fn new(vec: &'a mut Vector) -> crate::Result<Self> {
776         let mut ptr = std::ptr::null_mut();
777         let ierr = unsafe {
778             bind_ceed::CeedVectorGetArray(
779                 vec.ptr,
780                 crate::MemType::Host as bind_ceed::CeedMemType,
781                 &mut ptr,
782             )
783         };
784         vec.check_error(ierr)?;
785         Ok(Self {
786             vec: vec,
787             array: ptr,
788         })
789     }
790 }
791 
792 // Destructor
793 impl<'a> Drop for VectorViewMut<'a> {
794     fn drop(&mut self) {
795         unsafe {
796             bind_ceed::CeedVectorRestoreArray(self.vec.ptr, &mut self.array);
797         }
798     }
799 }
800 
801 // Data access
802 impl<'a> Deref for VectorViewMut<'a> {
803     type Target = [crate::Scalar];
804     fn deref(&self) -> &[crate::Scalar] {
805         unsafe { std::slice::from_raw_parts(self.array, self.vec.len()) }
806     }
807 }
808 
809 // Mutable data access
810 impl<'a> DerefMut for VectorViewMut<'a> {
811     fn deref_mut(&mut self) -> &mut [crate::Scalar] {
812         unsafe { std::slice::from_raw_parts_mut(self.array, self.vec.len()) }
813     }
814 }
815 
816 // Viewing
817 impl<'a> fmt::Display for VectorViewMut<'a> {
818     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
819         write!(f, "VectorViewMut({:?})", self.deref())
820     }
821 }
822 
823 // -----------------------------------------------------------------------------
824