Repository: damar-wicaksono/uqtestfuns (language: python)

Issue:
Add 10D Test Function with Decreasing Coefficients from Linkletter et al. (2006)
The ten-dimensional linear function with decreasing coefficients from Linkletter et al. (2006)[^1] (see Eq. (6)) is defined as follows:

$$
\mathcal{M}(\boldsymbol{x}) = 0.2 x_1 + \frac{0.2}{2} x_2 + \frac{0.2}{4} x_3 + \frac{0.2}{8} x_4 + + \frac{0.2}{16} x_5 + \frac{0.2}{32} x_6 + \frac{0.2}{64} x_7 + \frac{0.2}{128} x_8 + \epsilon
$$

where $\boldsymbol{x} = \{ x_1, \ldots, x_8 \}$ is the vector of input variables modeled as an independent uniform random variable in $[0, 1]^8$. $\epsilon$ is a random error generated from $\mathcal{N}(\mu = 0.0, \sigma^2=0.05)$. Although the model is defined to be of ten-dimensional, only eight input variables are active.

In the paper, the response is standardized (with mean 0 and standard deviation 1.0), but we will skip this in the implementation of the function in UQTestFuns. The candidate name for this function is `LinkLetter2006Decreasing`.

The model was used as a test function in the context of sensitivity analysis.

[^1]: C. Linkletter, D. Bingham, N. Hengartner, D. Higdon, and K. Q. Ye, “Variable Selection for Gaussian Process Models in Computer Experiments,” Technometrics, vol. 48, no. 4, pp. 478–490, Nov. 2006, doi: [10.1198/004017006000000228](https://doi.org/10.1198/004017006000000228).


Discussion / hints:

Fix patch:
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2e9c378..0441445 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- The ten-dimensional linear function with decreasing coefficients from
+  Linkletter et al. (2006) featuring only eight active input variables out of
+  ten; the function was used in the context of metamodeling and sensitivity
+  analysis.
 - The ten-dimensional linear function from Linkletter et al. (2006) featuring
   only four active input variables out of ten; the function was used
   in the context of metamodeling and sensitivity analysis.
diff --git a/docs/_toc.yml b/docs/_toc.yml
index f714cde..5cc6b44 100644
--- a/docs/_toc.yml
+++ b/docs/_toc.yml
@@ -126,6 +126,10 @@ parts:
             title: Lim et al. (2002) Non-Polynomial
           - file: test-functions/lim-poly
             title: Lim et al. (2002) Polynomial
+          - file: test-functions/linkletter-dec-coeffs
+            title: Linkletter et al. (2006) Dec. Coeffs.
+          - file: test-functions/linkletter-linear
+            title: Linkletter et al. (2006) Linear
           - file: test-functions/mclain-s1
             title: McLain S1
           - file: test-functions/mclain-s2
diff --git a/docs/fundamentals/metamodeling.md b/docs/fundamentals/metamodeling.md
index 9636a4f..f45f21c 100644
--- a/docs/fundamentals/metamodeling.md
+++ b/docs/fundamentals/metamodeling.md
@@ -18,52 +18,53 @@ kernelspec:
 The table below listed the available test functions typically used
 in the comparison of metamodeling approaches.
 
-|                                   Name                                    | Input Dimension |      Constructor       |
-|:-------------------------------------------------------------------------:|:---------------:|:----------------------:|
-|                   {ref}`Ackley <test-functions:ackley>`                   |        M        |       `Ackley()`       |
-|   {ref}`Alemazkoor & Meidani (2018) 2D <test-functions:alemazkoor-2d>`    |        2        |    `Alemazkoor2D()`    |
-|  {ref}`Alemazkoor & Meidani (2018) 20D <test-functions:alemazkoor-20d>`   |       20        |   `Alemazkoor20D()`    |
-|                 {ref}`Borehole <test-functions:borehole>`                 |        8        |      `Borehole()`      |
-|         {ref}`Cheng and Sandu (2010) 2D <test-functions:cheng2d>`         |        2        |       `Cheng2D`        |
-|            {ref}`Coffee Cup Model <test-functions:coffee-cup>`            |        2        |     `CoffeeCup()`      |
-|       {ref}`Currin et al. (1988) Sine <test-functions:currin-sine>`       |        1        |     `CurrinSine()`     |
-|            {ref}`Damped Cosine <test-functions:damped-cosine>`            |        1        |    `DampedCosine()`    |
-|        {ref}`Damped Oscillator <test-functions:damped-oscillator>`        |        7        |  `DampedOscillator()`  |
-|       {ref}`Dette & Pepelyshev (2010) 8D <test-functions:dette-8d>`       |        3        |      `Dette8D()`       |
-|   {ref}`Dette & Pepelyshev (2010) Curved <test-functions:dette-curved>`   |        3        |    `DetteCurved()`     |
-|  {ref}`Dette & Pepelyshev (2010) Exponential <test-functions:dette-exp>`  |        3        |      `DetteExp()`      |
-|                    {ref}`Flood <test-functions:flood>`                    |        8        |       `Flood()`        |
-|         {ref}`Forrester et al. (2008) <test-functions:forrester>`         |        1        |   `Forrester2008()`    |
-|               {ref}`(1st) Franke <test-functions:franke-1>`               |        2        |      `Franke1()`       |
-|               {ref}`(2nd) Franke <test-functions:franke-2>`               |        2        |      `Franke2()`       |
-|               {ref}`(3rd) Franke <test-functions:franke-3>`               |        2        |      `Franke3()`       |
-|               {ref}`(4th) Franke <test-functions:franke-4>`               |        2        |      `Franke4()`       |
-|               {ref}`(5th) Franke <test-functions:franke-5>`               |        2        |      `Franke5()`       |
-|               {ref}`(6th) Franke <test-functions:franke-6>`               |        2        |      `Franke6()`       |
-|             {ref}`Friedman (6D) <test-functions:friedman-6d>`             |        6        |     `Friedman6D()`     |
-|            {ref}`Friedman (10D) <test-functions:friedman-10d>`            |       10        |    `Friedman10D()`     |
-|        {ref}`Genz (Corner Peak) <test-functions:genz-corner-peak>`        |        M        |   `GenzCornerPeak()`   |
-|      {ref}`Gramacy (2007) 1D Sine <test-functions:gramacy-1d-sine>`       |        1        |   `Gramacy1DSine()`    |
-|          {ref}`Higdon (2002) Sine <test-functions:higdon-sine>`           |        1        |     `HigdonSine()`     |
-|     {ref}`Holsclaw et al. (2013) Sine <test-functions:holsclaw-sine>`     |        1        |    `HolsclawSine()`    |
-|   {ref}`Lim et al. (2002) Non-Polynomial <test-functions:lim-non-poly>`   |        2        |     `LimNonPoly()`     |
-|       {ref}`Lim et al. (2002) Polynomial <test-functions:lim-poly>`       |        2        |      `LimPoly()`       |
-| {ref}`Linkletter et al. (2006) Linear <test-functions:linkletter-linear>` |       10        |  `LinkletterLinear()`  |
-|                {ref}`McLain S1 <test-functions:mclain-s1>`                |        2        |      `McLainS1()`      |
-|                {ref}`McLain S2 <test-functions:mclain-s2>`                |        2        |      `McLainS2()`      |
-|                {ref}`McLain S3 <test-functions:mclain-s3>`                |        2        |      `McLainS3()`      |
-|                {ref}`McLain S4 <test-functions:mclain-s4>`                |        2        |      `McLainS4()`      |
-|                {ref}`McLain S5 <test-functions:mclain-s5>`                |        2        |      `McLainS5()`      |
-|       {ref}`Oakley & O'Hagan (2002) 1D <test-functions:oakley-1d>`        |        1        |      `Oakley1D()`      |
-|              {ref}`OTL Circuit <test-functions:otl-circuit>`              |     6 / 20      |     `OTLCircuit()`     |
-|             {ref}`Piston Simulation <test-functions:piston>`              |     7 / 20      |       `Piston()`       |
-|                {ref}`Robot Arm <test-functions:robot-arm>`                |        8        |      `RobotArm()`      |
-|            {ref}`Solar Cell Model <test-functions:solar-cell>`            |        5        |     `SolarCell()`      |
-|                   {ref}`Sulfur <test-functions:sulfur>`                   |        9        |       `Sulfur()`       |
-|      {ref}`Undamped Oscillator <test-functions:undamped-oscillator>`      |        6        | `UndampedOscillator()` |
-|        {ref}`Webster et al. (1996) 2D <test-functions:webster-2d>`        |        2        |     `Webster2D()`      |
-|           {ref}`Welch et al. (1992) <test-functions:welch1992>`           |       20        |     `Welch1992()`      |
-|              {ref}`Wing Weight <test-functions:wing-weight>`              |       10        |     `WingWeight()`     |
+|                                              Name                                               | Input Dimension |       Constructor       |
+|:-----------------------------------------------------------------------------------------------:|:---------------:|:-----------------------:|
+|                              {ref}`Ackley <test-functions:ackley>`                              |        M        |       `Ackley()`        |
+|              {ref}`Alemazkoor & Meidani (2018) 2D <test-functions:alemazkoor-2d>`               |        2        |    `Alemazkoor2D()`     |
+|             {ref}`Alemazkoor & Meidani (2018) 20D <test-functions:alemazkoor-20d>`              |       20        |    `Alemazkoor20D()`    |
+|                            {ref}`Borehole <test-functions:borehole>`                            |        8        |      `Borehole()`       |
+|                    {ref}`Cheng and Sandu (2010) 2D <test-functions:cheng2d>`                    |        2        |        `Cheng2D`        |
+|                       {ref}`Coffee Cup Model <test-functions:coffee-cup>`                       |        2        |      `CoffeeCup()`      |
+|                  {ref}`Currin et al. (1988) Sine <test-functions:currin-sine>`                  |        1        |     `CurrinSine()`      |
+|                       {ref}`Damped Cosine <test-functions:damped-cosine>`                       |        1        |    `DampedCosine()`     |
+|                   {ref}`Damped Oscillator <test-functions:damped-oscillator>`                   |        7        |  `DampedOscillator()`   |
+|                  {ref}`Dette & Pepelyshev (2010) 8D <test-functions:dette-8d>`                  |        3        |       `Dette8D()`       |
+|              {ref}`Dette & Pepelyshev (2010) Curved <test-functions:dette-curved>`              |        3        |     `DetteCurved()`     |
+|             {ref}`Dette & Pepelyshev (2010) Exponential <test-functions:dette-exp>`             |        3        |      `DetteExp()`       |
+|                               {ref}`Flood <test-functions:flood>`                               |        8        |        `Flood()`        |
+|                    {ref}`Forrester et al. (2008) <test-functions:forrester>`                    |        1        |    `Forrester2008()`    |
+|                          {ref}`(1st) Franke <test-functions:franke-1>`                          |        2        |       `Franke1()`       |
+|                          {ref}`(2nd) Franke <test-functions:franke-2>`                          |        2        |       `Franke2()`       |
+|                          {ref}`(3rd) Franke <test-functions:franke-3>`                          |        2        |       `Franke3()`       |
+|                          {ref}`(4th) Franke <test-functions:franke-4>`                          |        2        |       `Franke4()`       |
+|                          {ref}`(5th) Franke <test-functions:franke-5>`                          |        2        |       `Franke5()`       |
+|                          {ref}`(6th) Franke <test-functions:franke-6>`                          |        2        |       `Franke6()`       |
+|                        {ref}`Friedman (6D) <test-functions:friedman-6d>`                        |        6        |     `Friedman6D()`      |
+|                       {ref}`Friedman (10D) <test-functions:friedman-10d>`                       |       10        |     `Friedman10D()`     |
+|                   {ref}`Genz (Corner Peak) <test-functions:genz-corner-peak>`                   |        M        |   `GenzCornerPeak()`    |
+|                 {ref}`Gramacy (2007) 1D Sine <test-functions:gramacy-1d-sine>`                  |        1        |    `Gramacy1DSine()`    |
+|                     {ref}`Higdon (2002) Sine <test-functions:higdon-sine>`                      |        1        |     `HigdonSine()`      |
+|                {ref}`Holsclaw et al. (2013) Sine <test-functions:holsclaw-sine>`                |        1        |    `HolsclawSine()`     |
+|              {ref}`Lim et al. (2002) Non-Polynomial <test-functions:lim-non-poly>`              |        2        |     `LimNonPoly()`      |
+|                  {ref}`Lim et al. (2002) Polynomial <test-functions:lim-poly>`                  |        2        |       `LimPoly()`       |
+| {ref}`Linkletter et al. (2006) Decreasing Coefficients <test-functions:linkletter-dec-coeffs>`  |       10        | `LinkletterDecCoeffs()` |
+|            {ref}`Linkletter et al. (2006) Linear <test-functions:linkletter-linear>`            |       10        |  `LinkletterLinear()`   |
+|                           {ref}`McLain S1 <test-functions:mclain-s1>`                           |        2        |      `McLainS1()`       |
+|                           {ref}`McLain S2 <test-functions:mclain-s2>`                           |        2        |      `McLainS2()`       |
+|                           {ref}`McLain S3 <test-functions:mclain-s3>`                           |        2        |      `McLainS3()`       |
+|                           {ref}`McLain S4 <test-functions:mclain-s4>`                           |        2        |      `McLainS4()`       |
+|                           {ref}`McLain S5 <test-functions:mclain-s5>`                           |        2        |      `McLainS5()`       |
+|                  {ref}`Oakley & O'Hagan (2002) 1D <test-functions:oakley-1d>`                   |        1        |      `Oakley1D()`       |
+|                         {ref}`OTL Circuit <test-functions:otl-circuit>`                         |     6 / 20      |     `OTLCircuit()`      |
+|                        {ref}`Piston Simulation <test-functions:piston>`                         |     7 / 20      |       `Piston()`        |
+|                           {ref}`Robot Arm <test-functions:robot-arm>`                           |        8        |      `RobotArm()`       |
+|                       {ref}`Solar Cell Model <test-functions:solar-cell>`                       |        5        |      `SolarCell()`      |
+|                              {ref}`Sulfur <test-functions:sulfur>`                              |        9        |       `Sulfur()`        |
+|                 {ref}`Undamped Oscillator <test-functions:undamped-oscillator>`                 |        6        | `UndampedOscillator()`  |
+|                   {ref}`Webster et al. (1996) 2D <test-functions:webster-2d>`                   |        2        |      `Webster2D()`      |
+|                      {ref}`Welch et al. (1992) <test-functions:welch1992>`                      |       20        |      `Welch1992()`      |
+|                         {ref}`Wing Weight <test-functions:wing-weight>`                         |       10        |     `WingWeight()`      |
 
 In a Python terminal, you can list all the available functions relevant
 for metamodeling applications using ``list_functions()``
diff --git a/docs/fundamentals/sensitivity.md b/docs/fundamentals/sensitivity.md
index f96d9ba..20df329 100644
--- a/docs/fundamentals/sensitivity.md
+++ b/docs/fundamentals/sensitivity.md
@@ -18,33 +18,34 @@ kernelspec:
 The table below listed the available test functions typically used
 in the comparison of sensitivity analysis methods.
 
-|                                    Name                                    | Input Dimension |      Constructor       |
-|:--------------------------------------------------------------------------:|:---------------:|:----------------------:|
-|                 {ref}`Borehole <test-functions:borehole>`                  |        8        |      `Borehole()`      |
-|        {ref}`Bratley et al. (1992) A <test-functions:bratley1992a>`        |        M        |    `Bratley1992a()`    |
-|        {ref}`Bratley et al. (1992) B <test-functions:bratley1992b>`        |        M        |    `Bratley1992b()`    |
-|        {ref}`Bratley et al. (1992) C <test-functions:bratley1992c>`        |        M        |    `Bratley1992c()`    |
-|        {ref}`Bratley et al. (1992) D <test-functions:bratley1992d>`        |        M        |    `Bratley1992d()`    |
-|        {ref}`Damped Oscillator <test-functions:damped-oscillator>`         |        7        |  `DampedOscillator()`  |
-|                    {ref}`Flood <test-functions:flood>`                     |        8        |       `Flood()`        |
-|             {ref}`Friedman (6D) <test-functions:friedman-6d>`              |        6        |     `Friedman6D()`     |
-|        {ref}`Genz (Corner Peak) <test-functions:genz-corner-peak>`         |        M        |   `GenzCornerPeak()`   |
-|      {ref}`Genz (Discontinuous) <test-functions:genz-discontinuous>`       |        M        | `GenzDiscontinuous()`  |
-|                 {ref}`Ishigami <test-functions:ishigami>`                  |        3        |      `Ishigami()`      |
-| {ref}`Linkletter et al. (2006) Linear <test-functions:linkletter-linear>`  |       10        |  `LinkletterLinear()`  |
-|               {ref}`Moon (2010) 3D <test-functions:moon3d>`                |        3        |       `Moon3D()`       |
-|          {ref}`Morris et al. (2006) <test-functions:morris2006>`           |        M        |     `Morris2006()`     |
-|              {ref}`OTL Circuit <test-functions:otl-circuit>`               |     6 / 20      |     `OTLCircuit()`     |
-|              {ref}`Piston Simulation <test-functions:piston>`              |     7 / 20      |       `Piston()`       |
-|        {ref}`Simple Portfolio Model <test-functions:portfolio-3d>`         |        3        |    `Portfolio3D()`     |
-|           {ref}`SaltelliLinear <test-functions:saltelli-linear>`           |        M        |   `SaltelliLinear()`   |
-|                  {ref}`Sobol'-G <test-functions:sobol-g>`                  |        M        |       `SobolG()`       |
-|               {ref}`Sobol'-G* <test-functions:sobol-g-star>`               |        M        |     `SobolGStar()`     |
-|            {ref}`Sobol'-Levitan <test-functions:sobol-levitan>`            |        M        |    `SobolLevitan()`    |
-|            {ref}`Solar Cell Model <test-functions:solar-cell>`             |        5        |     `SolarCell()`      |
-|                   {ref}`Sulfur <test-functions:sulfur>`                    |        9        |       `Sulfur()`       |
-|           {ref}`Welch et al. (1992) <test-functions:welch1992>`            |       20        |     `Welch1992()`      |
-|              {ref}`Wing Weight <test-functions:wing-weight>`               |       10        |     `WingWeight()`     |
+|                                              Name                                               | Input Dimension |       Constructor        |
+|:-----------------------------------------------------------------------------------------------:|:---------------:|:------------------------:|
+|                            {ref}`Borehole <test-functions:borehole>`                            |        8        |       `Borehole()`       |
+|                  {ref}`Bratley et al. (1992) A <test-functions:bratley1992a>`                   |        M        |     `Bratley1992a()`     |
+|                  {ref}`Bratley et al. (1992) B <test-functions:bratley1992b>`                   |        M        |     `Bratley1992b()`     |
+|                  {ref}`Bratley et al. (1992) C <test-functions:bratley1992c>`                   |        M        |     `Bratley1992c()`     |
+|                  {ref}`Bratley et al. (1992) D <test-functions:bratley1992d>`                   |        M        |     `Bratley1992d()`     |
+|                   {ref}`Damped Oscillator <test-functions:damped-oscillator>`                   |        7        |   `DampedOscillator()`   |
+|                               {ref}`Flood <test-functions:flood>`                               |        8        |        `Flood()`         |
+|                        {ref}`Friedman (6D) <test-functions:friedman-6d>`                        |        6        |      `Friedman6D()`      |
+|                   {ref}`Genz (Corner Peak) <test-functions:genz-corner-peak>`                   |        M        |    `GenzCornerPeak()`    |
+|                 {ref}`Genz (Discontinuous) <test-functions:genz-discontinuous>`                 |        M        |  `GenzDiscontinuous()`   |
+|                            {ref}`Ishigami <test-functions:ishigami>`                            |        3        |       `Ishigami()`       |
+| {ref}`Linkletter et al. (2006) Decreasing Coefficients <test-functions:linkletter-dec-coeffs>`  |       10        | `LinkletterDecCoeffs()`  |
+|            {ref}`Linkletter et al. (2006) Linear <test-functions:linkletter-linear>`            |       10        |   `LinkletterLinear()`   |
+|                          {ref}`Moon (2010) 3D <test-functions:moon3d>`                          |        3        |        `Moon3D()`        |
+|                     {ref}`Morris et al. (2006) <test-functions:morris2006>`                     |        M        |      `Morris2006()`      |
+|                         {ref}`OTL Circuit <test-functions:otl-circuit>`                         |     6 / 20      |      `OTLCircuit()`      |
+|                        {ref}`Piston Simulation <test-functions:piston>`                         |     7 / 20      |        `Piston()`        |
+|                   {ref}`Simple Portfolio Model <test-functions:portfolio-3d>`                   |        3        |     `Portfolio3D()`      |
+|                     {ref}`SaltelliLinear <test-functions:saltelli-linear>`                      |        M        |    `SaltelliLinear()`    |
+|                            {ref}`Sobol'-G <test-functions:sobol-g>`                             |        M        |        `SobolG()`        |
+|                         {ref}`Sobol'-G* <test-functions:sobol-g-star>`                          |        M        |      `SobolGStar()`      |
+|                      {ref}`Sobol'-Levitan <test-functions:sobol-levitan>`                       |        M        |     `SobolLevitan()`     |
+|                       {ref}`Solar Cell Model <test-functions:solar-cell>`                       |        5        |      `SolarCell()`       |
+|                              {ref}`Sulfur <test-functions:sulfur>`                              |        9        |        `Sulfur()`        |
+|                      {ref}`Welch et al. (1992) <test-functions:welch1992>`                      |       20        |      `Welch1992()`       |
+|                         {ref}`Wing Weight <test-functions:wing-weight>`                         |       10        |      `WingWeight()`      |
 
 In a Python terminal, you can list all the available functions relevant
 for metamodeling applications using ``list_functions()``


Test patch:
diff --git a/docs/test-functions/available.md b/docs/test-functions/available.md
index 64da08c..c9eee7d 100644
--- a/docs/test-functions/available.md
+++ b/docs/test-functions/available.md
@@ -19,79 +19,80 @@ The table below lists all the test functions available in UQTestFuns
 from the uncertainty quantification (UQ) literature,
 regardless of their typical applications.
 
-|                                        Name                                         | Input Dimension |           Constructor           |
-|:-----------------------------------------------------------------------------------:|:---------------:|:-------------------------------:|
-|                        {ref}`Ackley <test-functions:ackley>`                        |        M        |           `Ackley()`            |
-|        {ref}`Alemazkoor & Meidani (2018) 2D <test-functions:alemazkoor-2d>`         |        2        |        `Alemazkoor2D()`         |
-|       {ref}`Alemazkoor & Meidani (2018) 20D <test-functions:alemazkoor-20d>`        |       20        |        `Alemazkoor20D()`        |
-|                      {ref}`Borehole <test-functions:borehole>`                      |        8        |          `Borehole()`           |
-|            {ref}`Bratley et al. (1992) A <test-functions:bratley1992a>`             |        M        |        `Bratley1992a()`         |
-|            {ref}`Bratley et al. (1992) B <test-functions:bratley1992b>`             |        M        |        `Bratley1992b()`         |
-|            {ref}`Bratley et al. (1992) C <test-functions:bratley1992c>`             |        M        |        `Bratley1992c()`         |
-|            {ref}`Bratley et al. (1992) D <test-functions:bratley1992d>`             |        M        |        `Bratley1992d()`         |
-|           {ref}`Cantilever Beam (2D) <test-functions:cantilever-beam-2d>`           |        2        |       `CantileverBeam2D `       |
-|              {ref}`Cheng and Sandu (2010) 2D <test-functions:cheng2d>`              |        2        |           `Cheng2D `            |
-|           {ref}`Circular Pipe Crack <test-functions:circular-pipe-crack>`           |        2        |      `CircularPipeCrack()`      |
-|                 {ref}`Coffee Cup Model <test-functions:coffee-cup>`                 |        2        |          `CoffeeCup()`          |
-|            {ref}`Currin et al. (1988) Sine <test-functions:currin-sine>`            |        1        |         `CurrinSine()`          |
-|          {ref}`Convex Failure Domain <test-functions:convex-fail-domain>`           |        2        |      `ConvexFailDomain()`       |
-|                 {ref}`Damped Cosine <test-functions:damped-cosine>`                 |        1        |        `DampedCosine()`         |
-|             {ref}`Damped Oscillator <test-functions:damped-oscillator>`             |        7        |      `DampedOscillator()`       |
-| {ref}`Damped Oscillator Reliability <test-functions:damped-oscillator-reliability>` |        8        | `DampedOscillatorReliability()` |
-|            {ref}`Dette & Pepelyshev (2010) 8D <test-functions:dette-8d>`            |        3        |           `Dette8D()`           |
-|        {ref}`Dette & Pepelyshev (2010) Curved <test-functions:dette-curved>`        |        3        |         `DetteCurved()`         |
-|       {ref}`Dette & Pepelyshev (2010) Exponential <test-functions:dette-exp>`       |        3        |          `DetteExp()`           |
-|                         {ref}`Flood <test-functions:flood>`                         |        8        |            `Flood()`            |
-|              {ref}`Forrester et al. (2008) <test-functions:forrester>`              |        1        |        `Forrester2008()`        |
-|                   {ref}`Four-branch <test-functions:four-branch>`                   |        2        |         `FourBranch()`          |
-|                    {ref}`(1st) Franke <test-functions:franke-1>`                    |        2        |           `Franke1()`           |
-|                    {ref}`(2nd) Franke <test-functions:franke-2>`                    |        2        |           `Franke2()`           |
-|                    {ref}`(3rd) Franke <test-functions:franke-3>`                    |        2        |           `Franke3()`           |
-|                    {ref}`(4th) Franke <test-functions:franke-4>`                    |        2        |           `Franke4()`           |
-|                    {ref}`(5th) Franke <test-functions:franke-5>`                    |        2        |           `Franke5()`           |
-|                    {ref}`(6th) Franke <test-functions:franke-6>`                    |        2        |           `Franke6()`           |
-|                  {ref}`Friedman (6D) <test-functions:friedman-6d>`                  |        6        |         `Friedman6D()`          |
-|                 {ref}`Friedman (10D) <test-functions:friedman-10d>`                 |       10        |         `Friedman10D()`         |
-|                    {ref}`Gayton Hat <test-functions:gayton-hat>`                    |        2        |          `GaytonHat()`          |
-|              {ref}`Genz (Continuous) <test-functions:genz-continuous>`              |        M        |       `GenzContinuous()`        |
-|             {ref}`Genz (Corner Peak) <test-functions:genz-corner-peak>`             |        M        |       `GenzCornerPeak()`        |
-|           {ref}`Genz (Discontinuous) <test-functions:genz-discontinuous>`           |        M        |      `GenzDiscontinuous()`      |
-|                {ref}`Genz (Gaussian) <test-functions:genz-gaussian>`                |        M        |        `GenzGaussian()`         |
-|             {ref}`Genz (Oscillatory) <test-functions:genz-oscillatory>`             |        M        |       `GenzOscillatory()`       |
-|            {ref}`Genz (Product Peak) <test-functions:genz-product-peak>`            |        M        |       `GenzProductPeak()`       |
-|           {ref}`Gramacy (2007) 1D Sine <test-functions:gramacy-1d-sine>`            |        1        |        `Gramacy1DSine()`        |
-|               {ref}`Higdon (2002) Sine <test-functions:higdon-sine>`                |        1        |         `HigdonSine()`          |
-|          {ref}`Holsclaw et al. (2013) Sine <test-functions:holsclaw-sine>`          |        1        |        `HolsclawSine()`         |
-|               {ref}`Hyper-sphere Bound <test-functions:hyper-sphere>`               |        2        |         `HyperSphere()`         |
-|                      {ref}`Ishigami <test-functions:ishigami>`                      |        3        |          `Ishigami()`           |
-|        {ref}`Lim et al. (2002) Non-Polynomial <test-functions:lim-non-poly>`        |        2        |         `LimNonPoly()`          |
-|            {ref}`Lim et al. (2002) Polynomial <test-functions:lim-poly>`            |        2        |           `LimPoly()`           |
-|      {ref}`Linkletter et al. (2006) Linear <test-functions:linkletter-linear>`      |       10        |      `LinkletterLinear()`       |
-|                     {ref}`McLain S1 <test-functions:mclain-s1>`                     |        2        |          `McLainS1()`           |
-|                     {ref}`McLain S2 <test-functions:mclain-s2>`                     |        2        |          `McLainS2()`           |
-|                     {ref}`McLain S3 <test-functions:mclain-s3>`                     |        2        |          `McLainS3()`           |
-|                     {ref}`McLain S4 <test-functions:mclain-s4>`                     |        2        |          `McLainS4()`           |
-|                     {ref}`McLain S5 <test-functions:mclain-s5>`                     |        2        |          `McLainS5()`           |
-|                    {ref}`Moon (2010) 3D <test-functions:moon3d>`                    |        3        |           `Moon3D()`            |
-|               {ref}`Morris et al. (2006) <test-functions:morris2006>`               |        M        |         `Morris2006()`          |
-|            {ref}`Oakley & O'Hagan (2002) 1D <test-functions:oakley-1d>`             |        1        |          `Oakley1D()`           |
-|                   {ref}`OTL Circuit <test-functions:otl-circuit>`                   |     6 / 20      |         `OTLCircuit()`          |
-|                  {ref}`Piston Simulation <test-functions:piston>`                   |     7 / 20      |           `Piston()`            |
-|             {ref}`Simple Portfolio Model <test-functions:portfolio-3d>`             |        3        |         `Portfolio3D()`         |
-|                     {ref}`Robot Arm <test-functions:robot-arm>`                     |        8        |          `RobotArm()`           |
-|              {ref}`RS - Circular Bar <test-functions:rs-circular-bar>`              |        2        |        `RSCircularBar()`        |
-|                 {ref}`RS - Quadratic <test-functions:rs-quadratic>`                 |        2        |         `RSQuadratic()`         |
-|               {ref}`SaltelliLinear <test-functions:saltelli-linear>`                |        M        |       `SaltelliLinear()`        |
-|                      {ref}`Sobol'-G <test-functions:sobol-g>`                       |        M        |           `SobolG()`            |
-|                   {ref}`Sobol'-G* <test-functions:sobol-g-star>`                    |        M        |         `SobolGStar()`          |
-|                {ref}`Sobol'-Levitan <test-functions:sobol-levitan>`                 |        M        |        `SobolLevitan()`         |
-|                 {ref}`Solar Cell Model <test-functions:solar-cell>`                 |        5        |          `SolarCell()`          |
-|           {ref}`Speed Reducer Shaft <test-functions:speed-reducer-shaft>`           |        5        |      `SpeedReducerShaft()`      |
-|                        {ref}`Sulfur <test-functions:sulfur>`                        |        9        |           `Sulfur()`            |
-|           {ref}`Undamped Oscillator <test-functions:undamped-oscillator>`           |        6        |     `UndampedOscillator()`      |
-|             {ref}`Webster et al. (1996) 2D <test-functions:webster-2d>`             |        2        |          `Webster2D()`          |
-|                {ref}`Welch et al. (1992) <test-functions:welch1992>`                |       20        |          `Welch1992()`          |
-|                   {ref}`Wing Weight <test-functions:wing-weight>`                   |       10        |         `WingWeight()`          |
+|                                              Name                                              | Input Dimension |           Constructor           |
+|:----------------------------------------------------------------------------------------------:|:---------------:|:-------------------------------:|
+|                             {ref}`Ackley <test-functions:ackley>`                              |        M        |           `Ackley()`            |
+|              {ref}`Alemazkoor & Meidani (2018) 2D <test-functions:alemazkoor-2d>`              |        2        |        `Alemazkoor2D()`         |
+|             {ref}`Alemazkoor & Meidani (2018) 20D <test-functions:alemazkoor-20d>`             |       20        |        `Alemazkoor20D()`        |
+|                           {ref}`Borehole <test-functions:borehole>`                            |        8        |          `Borehole()`           |
+|                  {ref}`Bratley et al. (1992) A <test-functions:bratley1992a>`                  |        M        |        `Bratley1992a()`         |
+|                  {ref}`Bratley et al. (1992) B <test-functions:bratley1992b>`                  |        M        |        `Bratley1992b()`         |
+|                  {ref}`Bratley et al. (1992) C <test-functions:bratley1992c>`                  |        M        |        `Bratley1992c()`         |
+|                  {ref}`Bratley et al. (1992) D <test-functions:bratley1992d>`                  |        M        |        `Bratley1992d()`         |
+|                {ref}`Cantilever Beam (2D) <test-functions:cantilever-beam-2d>`                 |        2        |       `CantileverBeam2D `       |
+|                   {ref}`Cheng and Sandu (2010) 2D <test-functions:cheng2d>`                    |        2        |           `Cheng2D `            |
+|                {ref}`Circular Pipe Crack <test-functions:circular-pipe-crack>`                 |        2        |      `CircularPipeCrack()`      |
+|                      {ref}`Coffee Cup Model <test-functions:coffee-cup>`                       |        2        |          `CoffeeCup()`          |
+|                 {ref}`Currin et al. (1988) Sine <test-functions:currin-sine>`                  |        1        |         `CurrinSine()`          |
+|                {ref}`Convex Failure Domain <test-functions:convex-fail-domain>`                |        2        |      `ConvexFailDomain()`       |
+|                      {ref}`Damped Cosine <test-functions:damped-cosine>`                       |        1        |        `DampedCosine()`         |
+|                  {ref}`Damped Oscillator <test-functions:damped-oscillator>`                   |        7        |      `DampedOscillator()`       |
+|      {ref}`Damped Oscillator Reliability <test-functions:damped-oscillator-reliability>`       |        8        | `DampedOscillatorReliability()` |
+|                 {ref}`Dette & Pepelyshev (2010) 8D <test-functions:dette-8d>`                  |        3        |           `Dette8D()`           |
+|             {ref}`Dette & Pepelyshev (2010) Curved <test-functions:dette-curved>`              |        3        |         `DetteCurved()`         |
+|            {ref}`Dette & Pepelyshev (2010) Exponential <test-functions:dette-exp>`             |        3        |          `DetteExp()`           |
+|                              {ref}`Flood <test-functions:flood>`                               |        8        |            `Flood()`            |
+|                   {ref}`Forrester et al. (2008) <test-functions:forrester>`                    |        1        |        `Forrester2008()`        |
+|                        {ref}`Four-branch <test-functions:four-branch>`                         |        2        |         `FourBranch()`          |
+|                         {ref}`(1st) Franke <test-functions:franke-1>`                          |        2        |           `Franke1()`           |
+|                         {ref}`(2nd) Franke <test-functions:franke-2>`                          |        2        |           `Franke2()`           |
+|                         {ref}`(3rd) Franke <test-functions:franke-3>`                          |        2        |           `Franke3()`           |
+|                         {ref}`(4th) Franke <test-functions:franke-4>`                          |        2        |           `Franke4()`           |
+|                         {ref}`(5th) Franke <test-functions:franke-5>`                          |        2        |           `Franke5()`           |
+|                         {ref}`(6th) Franke <test-functions:franke-6>`                          |        2        |           `Franke6()`           |
+|                       {ref}`Friedman (6D) <test-functions:friedman-6d>`                        |        6        |         `Friedman6D()`          |
+|                      {ref}`Friedman (10D) <test-functions:friedman-10d>`                       |       10        |         `Friedman10D()`         |
+|                         {ref}`Gayton Hat <test-functions:gayton-hat>`                          |        2        |          `GaytonHat()`          |
+|                   {ref}`Genz (Continuous) <test-functions:genz-continuous>`                    |        M        |       `GenzContinuous()`        |
+|                  {ref}`Genz (Corner Peak) <test-functions:genz-corner-peak>`                   |        M        |       `GenzCornerPeak()`        |
+|                {ref}`Genz (Discontinuous) <test-functions:genz-discontinuous>`                 |        M        |      `GenzDiscontinuous()`      |
+|                     {ref}`Genz (Gaussian) <test-functions:genz-gaussian>`                      |        M        |        `GenzGaussian()`         |
+|                  {ref}`Genz (Oscillatory) <test-functions:genz-oscillatory>`                   |        M        |       `GenzOscillatory()`       |
+|                 {ref}`Genz (Product Peak) <test-functions:genz-product-peak>`                  |        M        |       `GenzProductPeak()`       |
+|                 {ref}`Gramacy (2007) 1D Sine <test-functions:gramacy-1d-sine>`                 |        1        |        `Gramacy1DSine()`        |
+|                     {ref}`Higdon (2002) Sine <test-functions:higdon-sine>`                     |        1        |         `HigdonSine()`          |
+|               {ref}`Holsclaw et al. (2013) Sine <test-functions:holsclaw-sine>`                |        1        |        `HolsclawSine()`         |
+|                    {ref}`Hyper-sphere Bound <test-functions:hyper-sphere>`                     |        2        |         `HyperSphere()`         |
+|                           {ref}`Ishigami <test-functions:ishigami>`                            |        3        |          `Ishigami()`           |
+|             {ref}`Lim et al. (2002) Non-Polynomial <test-functions:lim-non-poly>`              |        2        |         `LimNonPoly()`          |
+|                 {ref}`Lim et al. (2002) Polynomial <test-functions:lim-poly>`                  |        2        |           `LimPoly()`           |
+| {ref}`Linkletter et al. (2006) Decreasing Coefficients <test-functions:linkletter-dec-coeffs>` |       10        |     `LinkletterDecCoeffs()`     |
+|           {ref}`Linkletter et al. (2006) Linear <test-functions:linkletter-linear>`            |       10        |      `LinkletterLinear()`       |
+|                          {ref}`McLain S1 <test-functions:mclain-s1>`                           |        2        |          `McLainS1()`           |
+|                          {ref}`McLain S2 <test-functions:mclain-s2>`                           |        2        |          `McLainS2()`           |
+|                          {ref}`McLain S3 <test-functions:mclain-s3>`                           |        2        |          `McLainS3()`           |
+|                          {ref}`McLain S4 <test-functions:mclain-s4>`                           |        2        |          `McLainS4()`           |
+|                          {ref}`McLain S5 <test-functions:mclain-s5>`                           |        2        |          `McLainS5()`           |
+|                         {ref}`Moon (2010) 3D <test-functions:moon3d>`                          |        3        |           `Moon3D()`            |
+|                    {ref}`Morris et al. (2006) <test-functions:morris2006>`                     |        M        |         `Morris2006()`          |
+|                  {ref}`Oakley & O'Hagan (2002) 1D <test-functions:oakley-1d>`                  |        1        |          `Oakley1D()`           |
+|                        {ref}`OTL Circuit <test-functions:otl-circuit>`                         |     6 / 20      |         `OTLCircuit()`          |
+|                        {ref}`Piston Simulation <test-functions:piston>`                        |     7 / 20      |           `Piston()`            |
+|                  {ref}`Simple Portfolio Model <test-functions:portfolio-3d>`                   |        3        |         `Portfolio3D()`         |
+|                          {ref}`Robot Arm <test-functions:robot-arm>`                           |        8        |          `RobotArm()`           |
+|                   {ref}`RS - Circular Bar <test-functions:rs-circular-bar>`                    |        2        |        `RSCircularBar()`        |
+|                      {ref}`RS - Quadratic <test-functions:rs-quadratic>`                       |        2        |         `RSQuadratic()`         |
+|                     {ref}`SaltelliLinear <test-functions:saltelli-linear>`                     |        M        |       `SaltelliLinear()`        |
+|                            {ref}`Sobol'-G <test-functions:sobol-g>`                            |        M        |           `SobolG()`            |
+|                         {ref}`Sobol'-G* <test-functions:sobol-g-star>`                         |        M        |         `SobolGStar()`          |
+|                      {ref}`Sobol'-Levitan <test-functions:sobol-levitan>`                      |        M        |        `SobolLevitan()`         |
+|                      {ref}`Solar Cell Model <test-functions:solar-cell>`                       |        5        |          `SolarCell()`          |
+|                {ref}`Speed Reducer Shaft <test-functions:speed-reducer-shaft>`                 |        5        |      `SpeedReducerShaft()`      |
+|                             {ref}`Sulfur <test-functions:sulfur>`                              |        9        |           `Sulfur()`            |
+|                {ref}`Undamped Oscillator <test-functions:undamped-oscillator>`                 |        6        |     `UndampedOscillator()`      |
+|                  {ref}`Webster et al. (1996) 2D <test-functions:webster-2d>`                   |        2        |          `Webster2D()`          |
+|                     {ref}`Welch et al. (1992) <test-functions:welch1992>`                      |       20        |          `Welch1992()`          |
+|                        {ref}`Wing Weight <test-functions:wing-weight>`                         |       10        |         `WingWeight()`          |
 
 In a Python terminal, you can list all the available functions
 along with the corresponding constructor using ``list_functions()``
diff --git a/docs/test-functions/linkletter-dec-coeffs.md b/docs/test-functions/linkletter-dec-coeffs.md
new file mode 100644
index 0000000..0224783
--- /dev/null
+++ b/docs/test-functions/linkletter-dec-coeffs.md
@@ -0,0 +1,126 @@
+---
+jupytext:
+  formats: ipynb,md:myst
+  text_representation:
+    extension: .md
+    format_name: myst
+    format_version: 0.13
+    jupytext_version: 1.14.1
+kernelspec:
+  display_name: Python 3 (ipykernel)
+  language: python
+  name: python3
+---
+
+(test-functions:linkletter-dec-coeffs)=
+# Linear Function with Decreasing Coefficients from Linkletter et al. (2006)
+
+```{code-cell} ipython3
+import numpy as np
+import matplotlib.pyplot as plt
+import uqtestfuns as uqtf
+```
+
+The linear function is a ten-dimensional, scalar-valued function whose
+coefficients are decreasing. Only the first eight input variables are active,
+while the rest is inert.
+The function was used in {cite}`Linkletter2006` to demonstrate a variable
+selection method (i.e., sensitivity analysis)
+in the context of Gaussian process metamodeling:
+
+```{note}
+Linkletter et al. {cite}`Linkletter2006` introduced four ten-dimensional
+analytical test functions with some of the input variables inert.
+They are used to demonstrate a variable selection method (i.e., screening)
+in the context of Gaussian process metamodeling:
+
+- {ref}`Linear <test-functions:linkletter-linear>` function features
+  a simple function with four active input variables (out of 10).
+- {ref}`Linear with decreasing coefficients <test-functions:linkletter-dec-coeffs>`
+  function features a slightly more complex linear function with eight active
+  input variables (out of 10). (_this function_)
+```
+
+
+## Test function instance
+
+To create a default instance of the test function:
+
+```{code-cell} ipython3
+my_testfun = uqtf.LinkletterDecCoeffs()
+```
+
+Check if it has been correctly instantiated:
+
+```{code-cell} ipython3
+print(my_testfun)
+```
+
+## Description
+
+The test function is defined as[^location]:
+
+$$
+\mathcal{M}(\boldsymbol{x}) = 0.2 \sum_{i = 1}^8 \frac{x_i}{2^{(i - 1)}}
+$$
+
+where $\boldsymbol{x} = \left( x_1, \ldots x_{10} \right)$
+is the ten-dimensional vector of input variables further defined below.
+Notice that only eight out of ten input variables are active.
+
+```{note}
+In the original paper, the function was added with an independent identically
+distributed (i.i.d) noise from $\mathcal{N}(0, \sigma)$
+with a standard deviation $\sigma = 0.05$.
+
+Furthermore, also in the original paper, a batch of data is generated from
+the function and then standardized to have mean $0.0$ and standard deviation
+$1.0$.
+
+The implementation of UQTestFuns does not include any error addition
+or standardization. However, these processes can be done manually
+after the data is generated.
+```
+
+## Probabilistic input
+
+The probabilistic input model for the test function is shown below.
+
+```{code-cell} ipython3
+:tags: [hide-input]
+
+print(my_testfun.prob_input)
+```
+
+## Reference results
+
+This section provides several reference results of typical UQ analyses
+involving the test function.
+
+### Sample histogram
+
+Shown below is the histogram of the output based on $100'000$ random points:
+
+```{code-cell} ipython3
+:tags: [hide-input]
+
+my_testfun.prob_input.reset_rng(42)
+xx_test = my_testfun.prob_input.get_sample(100000)
+yy_test = my_testfun(xx_test)
+
+plt.hist(yy_test, bins="auto", color="#8da0cb");
+plt.grid();
+plt.ylabel("Counts [-]");
+plt.xlabel("$\mathcal{M}(X)$");
+plt.gcf().tight_layout(pad=3.0)
+plt.gcf().set_dpi(150);
+```
+
+## References
+
+```{bibliography}
+:style: unsrtalpha
+:filter: docname in docnames
+```
+
+[^location]: see Eq. (6), Example 1, in {cite}`Linkletter2006`.
diff --git a/docs/test-functions/linkletter-linear.md b/docs/test-functions/linkletter-linear.md
index 33ccb85..addae96 100644
--- a/docs/test-functions/linkletter-linear.md
+++ b/docs/test-functions/linkletter-linear.md
@@ -36,6 +36,9 @@ in the context of Gaussian process metamodeling:
 - {ref}`Linear <test-functions:linkletter-linear>` function features
   a simple function with four active input variables (out of 10).
   (_this function_)
+- {ref}`Linear with decreasing coefficients <test-functions:linkletter-dec-coeffs>`
+  function features a slightly more complex linear function with eight active
+  input variables (out of 10).
 ```
 
 
@@ -58,7 +61,7 @@ print(my_testfun)
 The test function is defined as[^location]:
 
 $$
-\mathcal{M}(\boldsymbol{x}) = 0.2 (x_1 + x_2 + x_3 + x_4),
+\mathcal{M}(\boldsymbol{x}) = 0.2 \sum_{i = 1}^4 x_i,
 $$
 
 where $\boldsymbol{x} = \left( x_1, \ldots x_{10} \right)$
@@ -69,6 +72,14 @@ Notice that only four out of ten input variables are active.
 In the original paper, the function was added with an independent identically
 distributed (i.i.d) noise from $\mathcal{N}(0, \sigma)$
 with a standard deviation $\sigma = 0.05$.
+
+Furthermore, also in the original paper, a batch of data is generated from
+the function and then standardized to have mean $0.0$ and standard deviation
+$1.0$.
+
+The implementation of UQTestFuns does not include any error addition
+or standardization. However, these processes can be done manually
+after the data is generated.
 ```
 
 ## Probabilistic input
diff --git a/src/uqtestfuns/test_functions/__init__.py b/src/uqtestfuns/test_functions/__init__.py
index f85cbc5..bc2cec8 100644
--- a/src/uqtestfuns/test_functions/__init__.py
+++ b/src/uqtestfuns/test_functions/__init__.py
@@ -35,7 +35,7 @@
 from .hyper_sphere import HyperSphere
 from .ishigami import Ishigami
 from .lim import LimPoly, LimNonPoly
-from .linkletter import LinkletterLinear
+from .linkletter import LinkletterLinear, LinkletterDecCoeffs
 from .oakley2002 import Oakley1D
 from .otl_circuit import OTLCircuit
 from .mclain import McLainS1, McLainS2, McLainS3, McLainS4, McLainS5
@@ -105,6 +105,7 @@
     "Ishigami",
     "LimNonPoly",
     "LimPoly",
+    "LinkletterDecCoeffs",
     "LinkletterLinear",
     "Oakley1D",
     "OTLCircuit",
diff --git a/src/uqtestfuns/test_functions/linkletter.py b/src/uqtestfuns/test_functions/linkletter.py
index 25e3724..d1aa41e 100644
--- a/src/uqtestfuns/test_functions/linkletter.py
+++ b/src/uqtestfuns/test_functions/linkletter.py
@@ -8,7 +8,8 @@
 
 Available functions are:
 
-- Linear function with four active input variables (out of 10).
+- Linear function with four active input variables..
+- Linear function with decreasing coefficients, eight active input variables.
 
 References
 ----------
@@ -24,11 +25,11 @@
 from uqtestfuns.core.custom_typing import ProbInputSpecs
 from uqtestfuns.core.uqtestfun_abc import UQTestFunFixDimABC
 
-__all__ = ["LinkletterLinear"]
+__all__ = ["LinkletterLinear", "LinkletterDecCoeffs"]
 
 
 def evaluate_linear(xx: np.ndarray) -> np.ndarray:
-    """Evaluate the linear  function from Linkletter et al. (2006).
+    """Evaluate the linear function from Linkletter et al. (2006).
 
     Parameters
     ----------
@@ -47,6 +48,29 @@ def evaluate_linear(xx: np.ndarray) -> np.ndarray:
     return yy
 
 
+def evaluate_dec_coeffs(xx: np.ndarray) -> np.ndarray:
+    """Evaluate the linear function with decreasing coefficients.
+
+    Parameters
+    ----------
+    xx : np.ndarray
+        M-Dimensional input values given by an N-by-10 array where
+        N is the number of input values.
+
+    Returns
+    -------
+    np.ndarray
+        The output of the test function evaluated on the input values.
+        The output is a 1-dimensional array of length N.
+    """
+    exps = np.arange(8)  # 8 input variables are active
+    coeffs = 0.2 / 2**exps
+
+    yy = np.sum(coeffs * xx[:, :8], axis=1)
+
+    return yy
+
+
 class LinkletterLinear(UQTestFunFixDimABC):
     """A concrete implementation of the linear function."""
 
@@ -74,3 +98,35 @@ class LinkletterLinear(UQTestFunFixDimABC):
     _available_parameters = None
 
     evaluate = staticmethod(evaluate_linear)  # type: ignore
+
+
+class LinkletterDecCoeffs(UQTestFunFixDimABC):
+    """A concrete implementation of the linear with decreasing coefficients."""
+
+    _tags = ["metamodeling", "sensitivity"]
+    _description = (
+        "Linear function with decreasing coefficients from Linkletter et al. "
+        "(2006)"
+    )
+    _available_inputs: ProbInputSpecs = {
+        "Linkletter2006": {
+            "function_id": "LinkletterLinear",
+            "description": (
+                "Input specification for the linear test function with "
+                "decreasing coefficients Eq. (6) from Linkletter et al. (2006)"
+            ),
+            "marginals": [
+                {
+                    "name": f"x_{i + 1}",
+                    "distribution": "uniform",
+                    "parameters": [0, 1],
+                    "description": None,
+                }
+                for i in range(10)
+            ],
+            "copulas": None,
+        },
+    }
+    _available_parameters = None
+
+    evaluate = staticmethod(evaluate_dec_coeffs)  # type: ignore