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| Alternative names | Clough–Tocher | 
| De Rham complex families | \(\mathrm{C}^1\mathrm{P}^3\mathrm{\Lambda}^0(\mathcal{R})\) | 
| Abbreviated names | HCT, CT | 
| Degrees | \(3\leqslant k\) | 
| Reference cells | triangle | 
| DOFs | On each vertex: point evaluations, and point evaluations of first derivatives On each edge: normal derivative integral moments with a degree \(k-3\) Lagrange space, and integral moments with a degree \(k-4\) Lagrange space
 On each face: integral moments with a degree \(k-4\) Lagrange space
 | 
| Number of DOFs | triangle: \(12+6(k-3)+(k-3)(k-2)/2\) | 
| Mapping | identity | 
| continuity | Function values and derivatives are continuous. | 
| Categories | Scalar-valued elements, Macro elements | 
This element is implemented in 
FIAT  and 
Symfem .
↓ Show implementation detail ↓↑ Hide implementation detail ↑| FIAT | FIAT.HsiehCloughTocher↓ Show FIAT examples ↓↑ Hide FIAT examples ↑
 This implementation is correct for all the examples below.Before running this example, you must install FIAT : pip3 install git+https://github.com/firedrakeproject/fiat.git This element can then be created with the following lines of Python: import FIAT
 # Create Hsieh-Clough-Tocher degree 3
 element = FIAT.HsiehCloughTocher(FIAT.ufc_cell("triangle"), 3)
 | 
| Symfem | "HCT"↓ Show Symfem examples ↓↑ Hide Symfem examples ↑
 This implementation is used to compute the examples below and verify other implementations.Before running this example, you must install Symfem : pip3 install symfem This element can then be created with the following lines of Python: import symfem
 # Create Hsieh-Clough-Tocher degree 3 on a triangle
 element = symfem.create_element("triangle", "HCT", 3)
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- Clough, Ray W. and Tocher, James L. Finite element stiffness matrices for analysis of plate bending, Proceedings of the First Conference on Matrix Methods in Structural Mechanics, 515–546, 1965. [BibTeX]
- Ciarlet, Philippe G. Interpolation error estimates for the reduced Hsieh–Clough–Tocher triangle, Mathematics of Computation 32, 335–344, 1978. [DOI: 10.1090/S0025-5718-1978-0482249-1] [BibTeX]
- Grošelj, Jan and Knez, Marjeta. Generalized C1 Clough–Tocher splines for CAGD and FEM, Computer Methods in Applied Mechanics and Engineering 395, 2022. [DOI: 10.1016/j.cma.2022.114983] [BibTeX]
| Element added | 08 March 2021 | 
| Element last updated | 04 June 2025 |