NAG FL Interface
d06daf (dim2_​transform_​affine)

1 Purpose

2 Specification

3 Description

4 References

5 Arguments

1: $\mathbf{nv}$ – Integer Input

On entry: the total number of vertices in the input mesh.

Constraint: $\mathbf{nv}\ge 3$.

2: $\mathbf{nedge}$ – Integer Input

On entry: the number of the boundary or interface edges in the input mesh.

Constraint: $\mathbf{nedge}\ge 1$.

3: $\mathbf{nelt}$ – Integer Input

On entry: the number of triangles in the input mesh.

Constraint: $\mathbf{nelt}\le 2\times \mathbf{nv}-1$.

4: $\mathbf{ntrans}$ – Integer Input

On entry: the number of transformations of the input mesh.

Constraint: $\mathbf{ntrans}\ge 1$.

5: $\mathbf{itype}\left(\mathbf{ntrans}\right)$ – Integer array Input

On entry: $\mathbf{itype}\left(\mathit{i}\right)$, for $\mathit{i}=1,2,\dots ,\mathbf{ntrans}$, indicates the type of each transformation as follows:

$\mathbf{itype}\left(i\right)=0$

Identity transformation.

$\mathbf{itype}\left(i\right)=1$

Translation.

$\mathbf{itype}\left(i\right)=2$

Symmetric transformation with respect to a user-supplied line.

$\mathbf{itype}\left(i\right)=3$

Rotation.

$\mathbf{itype}\left(i\right)=4$

Scaling.

$\mathbf{itype}\left(i\right)=10$

User-supplied analytic transformation.

Note that the transformations are applied in the order described in itype.

Constraint: $\mathbf{itype}\left(\mathit{i}\right)=0$, $1$, $2$, $3$, $4$ or $10$, for $\mathit{i}=1,2,\dots ,\mathbf{ntrans}$.

6: $\mathbf{trans}(6,\mathbf{ntrans})$ – Real (Kind=nag_wp) array Input

On entry: the arguments for each transformation. For $i=1,2,\dots ,\mathbf{ntrans}$, $\mathbf{trans}(1,i)$ to $\mathbf{trans}(6,i)$ contain the arguments of the $i$th transformation.

If $\mathbf{itype}\left(i\right)=0$, elements $\mathbf{trans}(1,i)$ to $\mathbf{trans}(6,i)$ are not referenced.

If $\mathbf{itype}\left(i\right)=1$, the translation vector is $\overrightarrow{u}=\left(\begin{array}{c}a\\ b\end{array}\right)$, where $a=\mathbf{trans}(1,i)$ and $b=\mathbf{trans}(2,i)$, while elements $\mathbf{trans}(3,i)$ to $\mathbf{trans}(6,i)$ are not referenced.

If $\mathbf{itype}\left(i\right)=2$, the user-supplied line is the curve {$(x,y)\in {ℝ}^2$; such that $ax+by+c=0$}, where $a=\mathbf{trans}(1,i)$, $b=\mathbf{trans}(2,i)$ and $c=\mathbf{trans}(3,i)$, while elements $\mathbf{trans}(4,i)$ to $\mathbf{trans}(6,i)$ are not referenced.

If $\mathbf{itype}\left(i\right)=3$, the centre of the rotation is $(x_0,y_0)$ where $x_0=\mathbf{trans}(1,i)$ and $y_0=\mathbf{trans}(2,i)$, $\theta =\mathbf{trans}(3,i)$ is its angle in degrees, while elements $\mathbf{trans}(4,i)$ to $\mathbf{trans}(6,i)$ are not referenced.

If $\mathbf{itype}\left(i\right)=4$, $a=\mathbf{trans}(1,i)$ is the scaling coefficient in the $x$-direction, $b=\mathbf{trans}(2,i)$ is the scaling coefficient in the $y$-direction, and $(x_0,y_0)$ are the scaling centre coordinates, with $x_0=\mathbf{trans}(3,i)$ and $y_0=\mathbf{trans}(4,i)$; while elements $\mathbf{trans}(5,i)$ to $\mathbf{trans}(6,i)$ are not referenced.

If $\mathbf{itype}\left(i\right)=10$, the user-supplied analytic affine transformation $Y=A\times X+B$ is such that $A={\left(a_{kl}\right)}_{1\le k,l\le 2}$ and $B={\left(b_k\right)}_{1\le k\le 2}$ where$a_{kl}=\mathbf{trans}(2\times (k-1)+l,i)$, and $b_k=\mathbf{trans}(4+k,i)$ with $k,l=1,2$.

7: $\mathbf{coori}(2,\mathbf{nv})$ – Real (Kind=nag_wp) array Input/Output

On entry: $\mathbf{coori}(1,\mathit{i})$ contains the $x$ coordinate of the $\mathit{i}$th vertex of the input mesh, for $\mathit{i}=1,2,\dots ,\mathbf{nv}$; while $\mathbf{coori}(2,i)$ contains the corresponding $y$ coordinate.

On exit: see Section 9.

8: $\mathbf{edgei}(3,\mathbf{nedge})$ – Integer array Input/Output

On entry: the specification of the boundary or interface edges. $\mathbf{edgei}(1,j)$ and $\mathbf{edgei}(2,j)$ contain the vertex numbers of the two end points of the $j$th boundary edge. $\mathbf{edgei}(3,j)$ is a user-supplied tag for the $j$th boundary edge.

Constraint: $1\le \mathbf{edgei}(\mathit{i},\mathit{j})\le \mathbf{nv}$ and $\mathbf{edgei}(1,\mathit{j})\ne \mathbf{edgei}(2,\mathit{j})$, for $\mathit{i}=1,2$ and $\mathit{j}=1,2,\dots ,\mathbf{nedge}$.

On exit: see Section 9.

9: $\mathbf{conni}(3,\mathbf{nelt})$ – Integer array Input/Output

On entry: the connectivity of the input mesh between triangles and vertices. For each triangle $\mathit{j}$, $\mathbf{conni}(\mathit{i},\mathit{j})$ gives the indices of its three vertices (in anticlockwise order), for $\mathit{i}=1,2,3$ and $\mathit{j}=1,2,\dots ,\mathbf{nelt}$.

Constraints:

• $1\le \mathbf{conni}(i,j)\le \mathbf{nv}$;
• $\mathbf{conni}(1,j)\ne \mathbf{conni}(2,j)$;
• $\mathbf{conni}(1,\mathit{j})\ne \mathbf{conni}(3,\mathit{j})$ and $\mathbf{conni}(2,\mathit{j})\ne \mathbf{conni}(3,\mathit{j})$, for $\mathit{i}=1,2,3$ and $\mathit{j}=1,2,\dots ,\mathbf{nelt}$.

On exit: see Section 9.

10: $\mathbf{cooro}(2,\mathbf{nv})$ – Real (Kind=nag_wp) array Output

On exit: $\mathbf{cooro}(1,\mathit{i})$ will contain the $x$ coordinate of the $\mathit{i}$th vertex of the transformed mesh, for $\mathit{i}=1,2,\dots ,\mathbf{nv}$; while $\mathbf{cooro}(2,i)$ will contain the corresponding $y$ coordinate.

11: $\mathbf{edgeo}(3,\mathbf{nedge})$ – Integer array Output

On exit: the specification of the boundary or interface edges of the transformed mesh. If the number of symmetric transformations is even or zero then$\mathbf{edgeo}(\mathit{i},\mathit{j})=\mathbf{edgei}(\mathit{i},\mathit{j})$, for $\mathit{i}=1,2,3$ and $\mathit{j}=1,2,\dots ,\mathbf{nedge}$; otherwise $\mathbf{edgeo}(1,\mathit{j})=\mathbf{edgei}(2,\mathit{j})$,$\mathbf{edgeo}(2,\mathit{j})=\mathbf{edgei}(1,\mathit{j})$ and $\mathbf{edgeo}(3,\mathit{j})=\mathbf{edgei}(3,\mathit{j})$, for $\mathit{j}=1,2,\dots ,\mathbf{nedge}$.

12: $\mathbf{conno}(3,\mathbf{nelt})$ – Integer array Output

On exit: the connectivity of the transformed mesh between triangles and vertices. If the number of symmetric transformations is even or zero then$\mathbf{conno}(\mathit{i},\mathit{j})=\mathbf{conni}(\mathit{i},\mathit{j})$, for $\mathit{i}=1,2,3$ and $\mathit{j}=1,2,\dots ,\mathbf{nelt}$; otherwise $\mathbf{conno}(1,\mathit{j})=\mathbf{conni}(1,\mathit{j})$, $\mathbf{conno}(2,\mathit{j})=\mathbf{conni}(3,\mathit{j})$ and $\mathbf{conno}(3,\mathit{j})=\mathbf{conni}(2,\mathit{j})$, for $\mathit{j}=1,2,\dots ,\mathbf{nelt}$.

13: $\mathbf{itrace}$ – Integer Input

On entry: the level of trace information required from d06daf.

$\mathbf{itrace}\le 0$

No output is generated.

$\mathbf{itrace}\ge 1$

Details of each transformation, the matrix $A$ and the vector $B$ of the final transformation, which is the composition of all the ntrans transformations, are printed on the current advisory message unit (see x04abf).

14: $\mathbf{rwork}\left(\mathbf{lrwork}\right)$ – Real (Kind=nag_wp) array Workspace

15: $\mathbf{lrwork}$ – Integer Input

On entry: the dimension of the array rwork as declared in the (sub)program from which d06daf is called.

Constraint: $\mathbf{lrwork}\ge 12\times \mathbf{ntrans}$.

16: $\mathbf{ifail}$ – Integer Input/Output

On entry: ifail must be set to $0$, $\mathrm{-1}$ or $1$ to set behaviour on detection of an error; these values have no effect when no error is detected.

A value of $0$ causes the printing of an error message and program execution will be halted; otherwise program execution continues. A value of $\mathrm{-1}$ means that an error message is printed while a value of $1$ means that it is not.

If halting is not appropriate, the value $\mathrm{-1}$ or $1$ is recommended. If message printing is undesirable, then the value $1$ is recommended. Otherwise, the value $0$ is recommended. When the value $-\mathbf{1}$ or $\mathbf{1}$ is used it is essential to test the value of ifail on exit.

On exit: $\mathbf{ifail}=\mathbf{0}$ unless the routine detects an error or a warning has been flagged (see Section 6).

6 Error Indicators and Warnings

$\mathbf{ifail}=1$

On entry, $\mathbf{conni}(\mathit{I},\mathit{J})=⟨\mathit{\text{value}}⟩$, $\mathit{I}=⟨\mathit{\text{value}}⟩$, $\mathit{J}=⟨\mathit{\text{value}}⟩$ and $\mathbf{nv}=⟨\mathit{\text{value}}⟩$.
Constraint: $\mathbf{conni}(\mathit{I},\mathit{J})\ge 1$ and $\mathbf{conni}(\mathit{I},\mathit{J})\le \mathbf{nv}$.

On entry, $\mathbf{edgei}(\mathit{I},\mathit{J})=⟨\mathit{\text{value}}⟩$, $\mathit{I}=⟨\mathit{\text{value}}⟩$, $\mathit{J}=⟨\mathit{\text{value}}⟩$ and $\mathbf{nv}=⟨\mathit{\text{value}}⟩$.
Constraint: $\mathbf{edgei}(\mathit{I},\mathit{J})\ge 1$ and $\mathbf{edgei}(\mathit{I},\mathit{J})\le \mathbf{nv}$.

On entry, $\mathbf{itype}\left(\mathit{I}\right)=⟨\mathit{\text{value}}⟩$ and $\mathit{I}=⟨\mathit{\text{value}}⟩$.
Constraint: $\mathbf{itype}\left(\mathit{I}\right)=0$, $1$, $2$, $3$, $4$ or $10$.

On entry, $\mathbf{lrwork}=⟨\mathit{\text{value}}⟩$ and $\mathrm{LRWKMN}=⟨\mathit{\text{value}}⟩$.
Constraint: $\mathbf{lrwork}\ge \mathrm{LRWKMN}$.

On entry, $\mathbf{nedge}=⟨\mathit{\text{value}}⟩$.
Constraint: $\mathbf{nedge}\ge 1$.

On entry, $\mathbf{nelt}=⟨\mathit{\text{value}}⟩$ and $\mathbf{nv}=⟨\mathit{\text{value}}⟩$.
Constraint: $\mathbf{nelt}\le 2\times \mathbf{nv}-1$.

On entry, $\mathbf{ntrans}=⟨\mathit{\text{value}}⟩$.
Constraint: $\mathbf{ntrans}>0$.

On entry, $\mathbf{nv}=⟨\mathit{\text{value}}⟩$.
Constraint: $\mathbf{nv}\ge 3$.

On entry, the end points of the edge $\mathit{J}$ have the same index $\mathit{I}$: $\mathit{J}=⟨\mathit{\text{value}}⟩$ and $\mathit{I}=⟨\mathit{\text{value}}⟩$.

On entry, vertices $1$ and $2$ of the triangle $\mathit{K}$ have the same index $\mathit{I}$: $\mathit{K}=⟨\mathit{\text{value}}⟩$ and $\mathit{I}=⟨\mathit{\text{value}}⟩$.

On entry, vertices $1$ and $3$ of the triangle $\mathit{K}$ have the same index $\mathit{I}$: $\mathit{K}=⟨\mathit{\text{value}}⟩$ and $\mathit{I}=⟨\mathit{\text{value}}⟩$.

On entry, vertices $2$ and $3$ of the triangle $\mathit{K}$ have the same index $\mathit{I}$: $\mathit{K}=⟨\mathit{\text{value}}⟩$ and $\mathit{I}=⟨\mathit{\text{value}}⟩$.

$\mathbf{ifail}=2$

A serious error has occurred in an internal call to an auxiliary routine. Check the input mesh especially the connectivities and the details of each transformations.

$\mathbf{ifail}=-99$

An unexpected error has been triggered by this routine. Please contact NAG.

See Section 7 in the Introduction to the NAG Library FL Interface for further information.

$\mathbf{ifail}=-399$

Your licence key may have expired or may not have been installed correctly.

See Section 8 in the Introduction to the NAG Library FL Interface for further information.

$\mathbf{ifail}=-999$

Dynamic memory allocation failed.

See Section 9 in the Introduction to the NAG Library FL Interface for further information.

7 Accuracy

8 Parallelism and Performance

9 Further Comments

10 Example